BG-272 DIY 2 x 72" Belt Grinder

DIY 2" x 72" Belt Grinder Project


Like almost every newbie knifemaker owning a decent belt grinder is dream. When I realized the price of a machine, my jaw hit the floor. Most of us getting started cannot afford a $2000 grinder. So I set out to design my own and I shamelessly borrowed as many ideas as I could. One special shout out to Alaskabearhawk for his great design and detailed videos on YouTube. If you are not sure about making this grinder, there is well made and very reasonable Ready to go grinder based on my plans.
















Wish List

My wish list for my new grinder would be:

  • 2 x 72" belts
  • 1.5 to 3 horsepower
  • Variable speed
  • Removable attachments, platen and contact wheel 

Variations


Before building I considered some variations:

Stepped sheaves for varying speed. This would be a lower cost build, but still allow some speed changing. I would need two pillow blocks, an axle and a stepped sheaves (or pulleys as some folks call them). The drive wheel could be 4" diameter still. This arrangement would let me use any motor, whether it can be reversed or not.

Fixed speed would be lowest cost and simplest build as there are less components and less alignment issues. The motor can be 2 pole or 4 pole and must be rotating in the CCW direction. That's fairly easy. Drive wheel size becomes a focus. For a 1800 RPM (4 pole) motor I'd use a 5" or 6" wheel. 2335 or 2826 surface feet per minute. For a 3600 RPM (2 pole) motor I'd use a 3" or 4" wheel. 2826 or 3768 surface feet per minute.

To get the surface feet per minute, use the formula:
(Motor Speed in RPM x 3.14 x Wheel Diameter) / 12.


Take a look at some of the other builds on the BG-272 Gallery of Builds page. Some very clever ideas going on there. Thanks to all that sent in photos and made such great suggestions.


Procurement

The search for suitable wheels proved fruitless as the most common maker in the US did not ship to Canada at the time. I found these wheels from Europe on eBay. You may want to check out Origin Blade Maker's belt grinder wheel set.






 Origin Blade Maker's Store
Origin Blade Maker's Store









Note: If you want to machine your own wheels, here is a PDF and a CAD drawing graciously provided by K. Langeveld.








For the drive wheel, I am using a 4" nylon caster that is 2" wide. I had to push the roller bearing race out and insert a shim with a 7/8" inside diameter. I then had to cut a key way for the 3/16" key stock. A fair bit of work, but I have made what is effectively a sub $20 crowned drive wheel.




The motor came from an ad on Kijiji . I scored this 2 horsepower T145C face motor, 3 phase 230/460V for a whopping $35. I wasn't too sure about this but after a quick ohm meter test and a spin of the shaft I think we're going to be fine.

For the variable speed part, I chose a Yaskawa J1000 VFD. My work associations with Yaskawa have been top notch over the years and basic shaft spinner came into my hands at a very reasonable price.

I am going to install the VFD in a sealed enclosure (NEMA 4) and wire a control panel for the operator to start, stop and vary the speed of the motor from the front of the grinder.

For the basic electrical I sourced from eBay, Digi-Key and my locals like Home Depot, Canadian Tire and Peavey Mart.


Not everyone can chance upon a nearly free motor.  I have made a Belt Grinder Motor Guide to help you in selecting a motor. Aside from a few electrical things, remember to check the shaft size on the motor and make sure the drive wheel's bore is a match. Drive wheels usually come with 5/8", 3/4" or 7/8" bores.






Construction

The basic construction is of HSS (Hollow Structural Steel) pieces and some plate and scrap pieces from my shop and from Metal Supermarket. The pieces I cut on a band saw so they are nice and square.

I bought 48" of 2" HSS, 0.188 wall and cut them like this.

















Very important! You must remove the seam inside the 2" HSS receivers before any welding takes place. This seam will prevent the inserted 1-1/2" tubing from sitting square inside their receiver. Use a long file or a small grinder wheel in a drill with an extension and remove the seam. Once the frame is welded, it becomes much more difficult to do this with a file.

As suggested by Ken DeRosier, make sure the welded seams are positioned on the left (where the lock down nuts will be installed.) This reduces the seams from being an issue, and provides a perfectly flat face for the tool arm to rest against.

Pieces A, B, C and D are squared, clamped and welded to make a frame like this.
















































I drilled some holes and tacked some 3/8" NC nuts for the lock downs.

I then welded the frame to a 12" x 20" plate of 1/4" steel, again checking for squareness and clamping everything in place before tacking.










I added four 1/4" x 1-1/2" studs for mounting the motor. These are flat head capscrews and I countersunk the underside so that they didn't stick out. I used hex nuts and placed fender washers on to support the motor. These being a bit smaller than the motor foot mount holes, allows for some rotating of the motor to get the belt to track properly. Also a  6" piece of strut to mount the operator control panel. The motor is positioned so that the center of the shaft is about 4" to the back of  the vertical receiver.




30 pound spring. Thanks Dave! I measured this on a scale. Pressing down on the spring about 30 pounds caused it to deflect 1". More recently, we have found that springs from screen door chains will work okay.






Update March 2017. I have made some better drawings of the frame.




























Tracking and Tensioning Pillar


The tracking and tensioning pillar slips into the upright receiver part C of our frame and sits on top of the spring. It has a tracking hinge that can be adjusted to tilt the tracking wheel.











The hinge part has a hole drilled right through, 3/4" from the top and 1-1/8" from the right side as shown. This hole must be offset from center to allow for the axle to go both positive and negative camber. This hole is slightly larger than the 1/4" bolt that will act as the hinge pin.

The axle hole is 2" from the top, centered.



The pillar itself is 13" long. This may have to change depending on the spring that you have available. My spring is about 4" long, so add or subtract a little if your spring is shorter or longer.

The axle hole is 3/4" from the top and centered on the 1-1/2" pillar  and is drilled right through. A drill press works well to keep this hole straight when drilling through. See photos below for construction.



The cutout hole for the tracking wheel axle is 2" from the top of the pillar so that the head of the axle bolt goes inside of this cutout. If you use a carriage head bolt for the axle, you need only make a round hole.




I clamped the hinge with shims around it before drilling a pilot hole right through both pieces on the drill press. Add 1/16" shims on the sides and 1/8" on the face. 







I tacked a flat washer on either side then hit them with the belt to thin them down to a good friction fit inside the hinge piece. The pillar will need an area removed for the bolt head of the tracking wheel axle to come through. If you were to use a carriage head bolt, this could be a circle. I had no luck finding a 12 mm carriage head, so I made a square to fit the hex head of the bolt.







 Test fitting the hinge.









The top and bottom of the pillar get capped with some 1/8" flat bar. Before tacking the top plate in, I drilled and inserted 5/16" x 1" bolt, then tacked that around the head. This will be for my shifter ball. (The ball will make it easier to push the pillar down.) 
Also note the 1/4" nut mounted for the tracking adjustment knob. The bolt going through here will press against the tracking wheel axle bolt and allow the tilt of the hinge to be adjusted.






The Platen Attachment

The platen attachment slide into a receiver and is locked in place. The tool arm is of 1-1/2" HSS with 0.250" wall that is 17" long. The plate that the wheels attach to is 3" x 12" made of 3/16" steel. I set the holes 10-3/8" apart so as to leave a good amount of space between them for a 9" platen. The platen is made from a piece of 2" angle iron. The angle is 0.188" thick.

I put a backing piece of 1/4" plate behind the angle to step it away from the plate. This could be accomplished with a small stack of flat washers as well. This space is to bring the platen directly in line with the belt and wheels. If you need to tweak the platen to the left or right, add or remove a washer from three bolts securing the platen to the plate.

The wheels are mounted typically with 1/2" bolts. In my case I have metric wheel bearings, so 12 mm bolts. The wheels cannot run against the plate, so I made some spacers from schedule 40 3/8" pipe cut into short sections about 1/4" and with a hacksaw and shaped with a file to uniform thickness of close to 3/16". Slip the spacer over the bolt, slide the wheel on and the inner race should be kissing the spacer.

Below are some updated drawings for the flat platen.






UPDATE: 
As some have mentioned, the 12 x 3" platen plate has limited space on the left side of the platen around the tool arm itself. One can grind above or below the centre, but when using a grinding jig on a fixed work rest the tool arm can get in the way. A slightly longer (and recommended) plate are shown below. 


This 12 x 4 plate offers better access to the platen on the left side near the centre of the platen. This  deeper plate will give an extra inch clearance in this area. The arc radius is the same, however the platen mounting is reduced to two points which works just fine. 





Tilt adjustment is made by loosening the two bolts and and adjusting. Once in the correct angle, lock the plate in place with the two bolts.







For the work rest, a found a piece of 1/4" thick plate about 4" x 6" and welded a piece of 3/8" x 3/4" bar stock to it. I drilled and made two slots for the 1/4" NC socket head capscrews to secure to the bottom of the tool arm.

Note that this work rest has been replaced with the Adjustable Work Rest.






Test fitting and tracking evaluation. Before painting, I added a 1/4" x 1/2" bolt on the vertical piece so I could mount a brush to remove static charge from the belt.

One thing to note here. The pillar is a little bit loose inside the vertical receiver. I added two strips of plastic (from an old oil jug) to act as shims. These are dusted with a little graphite to make them slippery.






I wanted to point you to Chris Fall's three part video build on YouTube. Chris uses slightly different materials, but his videos are great for showing the basic construction of his version of the BG-272.  











Unit painted.


Added the tool rest made of 1/4" plate on a 1/2" x 3/4" flat bar mounted to the underside of the platen tubing with 2 tapped 1/4" holes and hex socket capscrews to match.

Powered up the motor for live tracking test and VFD programming.







Grabbed two extension cords from different plugs in the garage and made 240V. A little high but should be ok. See the section on VFDs if you want to source 240V.
Powered up the VFD for initial programming.








VFD Power Wiring

The VFD requires a 240V / 20A supply. I have opted for a NEMA L6-20 receptacle and plug. The L means 'Locking' and this will assist in preventing any accidental un-plugging of said plug. I am using some supple SOOW 3 conductor #12 AWG for the input connection. I'd like some length so I piked up about 15 feet of this. Inside my VFD enclosure I have two midget type fuses that protect the VFD proper. A low current takeoff of 240V for the DC power supply is done immediately after the fusing. For convenience I've added some surplus terminal blocks mounted on DIN rail. The output of the VFD is rated for 10A (three phase) so I used some 4 conductor #14 AWG SOOW (cab tire) cable.



 

 


Operator's Control Panel

To control the VFD I am going to bring out the sequence inputs SC, S1, S3 and S5. This will allow me to START and STOP the motor as well as change the direction FWD and REV. I will also wire in the VFDs status contacts to drive two LEDs indicating motor on and off. Finally, I have a digital tachometer that will count pulses from a small magnet placed in the side of the drive wheel. The net result is that the operator's control panel will look something like this.






The magnetic (Hall effect IC) sensor that picks up magnetic field from the small magnet inserted into the drive wheel.








When the magnet passes close to the sensor the sensor switches to make a 24 VDC pulse going to the tachometer. This will count the revolutions per minute of the drive wheel.







To install the magnet in the drive wheel I drilled a 3/8" hole about 1/4" deep. Put a small daub of epoxy and pressed the magnet in with a vise.






The Hall effect sensor is mounted on the C-face of the motor and positioned about 1/4" away from the wheel so that the magnet passes near it each revolution.


Drilling the holes to get the jig saw blade in.
Masked off the face for drilling, jig sawing and filing the various cut out shapes.
Test fitting the tach.

Control and tachometer cables with strain reliefs in back of operator control panel enclosure. For the cable, I found some old-school 25 pin printer cable that has an overall shield.






Once the VFD enclosure was mounted to the frame, I could terminate one end of the control cable  accurately estimate the cable length for the motor. The control wiring is fairly straight forward. One thing to pay attention to is the wire colours. The particular printer cable I had has insulation that is colored solid and some with white stripes. These can be easy to mix up. A quick check put with the ohmmeter will save the day and prevent a mistake here.

I ended up with multiple wires going to +24V and common. I used some small wire nuts (Marettes), twisted all the +24V wires and cranked a wire nut on. As the LEDs already had wire leads on them I did solder splices and covered with some 1/8" heat shrink.







VFD Enclosure

The VFD enclosure is a surplus Hoffman NEMA 4 14" x 18" x 8". As it did not come with a mounting pan, I had to make one from something. Conveniently, I found some 1/8" utility grade aluminum that was pretty scratched up, but the price (free) was right.


I mounted the VFD and 24V power supply as well as some DIN rail to mount the terminal blocks.

For strain reliefs I used some nylon domed strain reliefs and one Heyco straight-thru for the tachometer sensor cable.





Tying it all Together

With the incoming power cord attached and the 4 wire motor lead connected it was a matter of programming the VFD to accept the 0-10V input (potentiometer) as the speed command and setting the top frequency to 80 Hz.  I also set the acceleration time to 5 seconds and deceleration to 2 seconds.



 



 

Running The Grinder

The first run with the unit complete involved a little tweak in the tracking hinge. The belt ran fairly true and didn't walk off the wheels at 4500 RPM.

 



 


 



I took a chew through some 154CM and the blaze belt eats it like butter. I am so impressed I will toss my hacksaw out!



 

 

 

 

Grinder Stand

The stand will hold the VFD enclosure and the grinder will be mounted on the top. For this I chose some scrap channel I had and welded it up. Adding two casters on the rear will allow easier moving, but only when tilting.


Before painting this space-ship silver, I welded some 5/16" x 1" flat head bolts to act as mounting studs for the grinder base.

Knowing where the motor and VFD enclosure line up, I can drill some holes for some chase nipples to pass the motor cable and control cable through the grinder base plate.







Small Wheel Attachment

July 8, 2014 - Small Wheel Attachment is now here.














10" Contact Wheel Attachment


October 2014 - 10" Contact Wheel Attachment is now here.


















Always updating. I will keep you posted.

Mechanical Bill of Materials is here.

Updated November 2019

Dan


286 comments:

«Oldest   ‹Older   201 – 286 of 286
Richard said...

Hi Dan, Great design! Very well explained, So much so that I think I can build my own. I do have one question though, in the updated plans there is a 1/8" sched 40 pipe,2" long welded, on the rear of the rear upright. Could you please explain as I can't figure it out? Many thanks, Richard

Unknown said...

Will a washing machine motor work?

Unknown said...

Hi Dan,
I just finished my grinder based on yours and it is a beast.
I used square receiver stock for the frame. A little expensive, but the inside/outside diameters were a perfect fit with no slop.
I used a 1 1/2 Hp motor from an old Taiwanese Delta table saw clone. The shaft is a little short, but the 5/8 bore, 4” wheel I purchased from Oregon Blademaker seems to be very secure.
Your diagrams and descriptions were great. The only trouble I had was lining up the motor mount bolts.
Thank you for your excellent blog.
Best, Robert

Unknown said...

This is incredible. I will be beginning this build soon. I have access to a full machinists shop so hopefully it'll go fairly easy.

Unknown said...

Just a not for other guys working on this, I got my motor with VFD from a great website, great price, and free shipping. Couldn't beat it. dealerselectric.com

Andreas said...

Seemsn no longer to be active. Any idea of a new site?

Unknown said...

Try looking for a diesel idler.

Varun Pendse said...

Hi Dan
I have a bench Grinder which runs at 2800RPM (As mentioned earlier) but the motor is only 0.25hp. Thought about using this instead of buying a motor.
What does this do to my build?

Varun Pendse said...

Hi, my belts keep slipping
What to do

Unknown said...

Hi Dan, thanks a lot for your work, you improve the hobbyist knifemaking world a lot.
I'm planning to make the BG-272 instead of the Sayber OSG because I dont have the money, but I want to make it tiltable.
Are there any reasons not to weld on a hinge like on the OSG ?
Or would it be better to have the table pivot like shown in the Gallery of builds ?
I'm using a C-face motor if that matters.

kenuto said...

the present time comments are not loading? Why I wonder?

D. Comeau said...

Hi, I noticed that comments were not appearing but couldn't put my finger on why. Thanks for your post as it sparked the investigation into why.

I understand that Blogger only does 200 comments on a given post and then it craps the bed. So sorry about this. But it's pop-up comment window moving forward.

Best wishes!

Dan

Varun Pendse said...

Hi Dan

Firstly, thank you for your help so far. Please reply to this comment on varunpendse@gmail.com as I am unable to access comments posted after October '17

I am using a drive Wheel made of wooden laminates. Haven't purchased the motor yet but am using a Bench Grinder as substitute, because I still need to align the belt. My problem here is that the belt keeps slipping off the assembly, and I have no Idea what to do. If you want, I can send you pictures via email, please reply to me on varunpendse@gmail.com

Thanks

Unknown said...

I hope you are still monitoring this blog...great design! I am currently in the process of building one of these myself and I have a few questions:
1. I have found, that in respect to frame parts A,B and C, if 1/4" wall tubing is used AND the inner weld seam is cleaned up, that 1-1/2" tubing (I have 1/8" on hand for fitting purposes only)fits perfectly and will slide with hardly any slop. Will this cause any fit problems further into the build?

2. I have a large sheet of 1/4" thick aluminum that would be perfect for the D-plate. If I used this in lieu of the .188 thickness recommended, would I encounter any fit or operational issues?

D. Comeau said...

You shouldn't have any issues with the 1/4" thick wall. I've seen about 100 made with 2" with 0.25" wall. Not a problem using the 1/4" aluminum for a platen plate. You can compensate for the extra 1/16" by reducing your platen wheel spacers. What's key is that the wheels are in a line when you're done.

Unknown said...

Sir can I know the Purpose of drilling hole in plate. What is the use of tilting plate in that design

D. Comeau said...

Having the platen adjustable allows one to square it 90° to the work rest table. This is useful when using grinding jigs.

Clay O said...

I just finished a 2x72 belt grinder build with the help of this site. I put a few of my own touches on it and I think it turned out Great! I went with a 2hp 3 phase motor, KBAC-27D VFD and Oregon Blade Makers Aluminum wheels. It is a beast and will greatly improve my knife making. Thanks a million. Clay

D. Comeau said...

That's great to hear Clay! Feel free to drop me a picture or two and I will add it to the Gallery of Builds. knives @ dcknives . com

Dan

Unknown said...

I appreciate all the effort that you have put into both your design and also the comprehensive information you have included on your site. I have one question about the frame and perhaps there is an obvious answer that I am overlooking.

From your diagram and parts list, it is clear that horizontal piece "A" is needed to complete the frame and act as the receiver for the platen tool arm but what is the purpose of horizontal piece "B"? I could see its use if one were to build a tool rest that required "B" to act as a receiver for that rest but in your design, the tool rest arm is mounted to the bottom of the platen tool arm.

Could you not have eliminated piece "B" and installed part "D" as a 6in. piece instead of a 4in. piece or would that have compromised the function of the tool?

D. Comeau said...

Hi Julian,

This design is known as a "two arm grinder" where the upper receiver is normally use for the platen or large wheel and the lower receiver is for the work rest. It could be any other fixture you want to add at a later date. I use it for the work rest, but others have used them for grinding jigs, surfacing attachments, work lights etc.

Any configuration, whether it's a one arm, as you proposed or two arm it will work fine as long as the members are welded squarely.

I hope this helps. Thanks for stopping by,

Dan

Unknown said...

Hello, I am building your grinder and want to purchase https://www.ebay.com/itm/231396771672. Will this size wheel work? I am very new to building items.

D. Comeau said...

That's an excellent wheel set, but your motor MUST have a 5/8" diameter motor shaft to work with this particular drive wheel. Typically NEMA 56 motors have 5/8" shafts. If your motor is a NEMA 143T or a 145T, then grab the wheel set with a 7/8" bore drive wheel. The rest of the wheels are the same only the drive wheel changes. Good luck!

Unknown said...

Sir, the tracking is killing me. I welded metal around the tracking arm. It helped a lot. but now part E is making it go far left. Causing it to cut into part E and the motor. I moved the motor forward and it stopped cutting into the motor but is still cutting into part E. If I twist part E to the left it will track center but when I apply pressure to the belt in a grind it moves far left again. please help, i have been stuck for two days.

D. Comeau said...

Mark, can you send me an email with a few pictures? Send it to knives @ dcknives . com (no spaces).

Dan

brazley said...

thanks dan--

simply phenomenal!! ive been pulling my hair out, just trying to get started (since i salvaged a treadmill motor and decided to tackle this), and then i found your build and plans. thank you so much for this blow by blow walk-through.

this is great and much appreciated, the best ive seen online. thanks dude!

courtney

:end

D. Comeau said...

I hope your build goes well. If you need any tips, chime in.

Cheers!

Dan

FERNET said...

QUERIA AGRADECER POR EL TUTORIAL, TENGO UNA MAQUINA ARMADA GRACIAS A SU AYUDA Y ESTOY MUY FELIZ, GRACIAS POR SUS APORTES .

Unknown said...

Hey thanks for the updated plans could you maybe update the plans or prints for the grinder Wheels I can't read the measurements when I print them out thanks thanks in advance

D. Comeau said...

Hi Jake. Do you mean the PDF file that was provided to machine the idler wheels?

Unknown said...

Does anyone have the dimensions of the hollow frame? I see where its marked up with letters but I dont see the actual lengths of the 2" square tubing, I must be missing it because no one else has asked for the lengths. Maybe a link to the actual plans?
Thanks

D. Comeau said...

Hi,

Yes the small numbers beside or inside the shapes on some of the mechanical drawings. The 2" HSS piece dimensions are: A, B and C = 10"; D = 4" and E is cut on an angle where one side is 3.5" and the opposite side is 1".

Hope this helps.

Dan

Unknown said...

If you move the welded nuts on the 2x2 to engage the top angle of the 1.5 inch,just slightly above it you’ll get a outward and down ward vector, is this a good idea?

D. Comeau said...

Changing the position vertically inside the receiver shouldn't be an issue. As long as the tool arm is to the right side the belt path and wheels will stay in line. Some guys drill the receiver at the top left corner and weld the nut there at 45°. The locking bolt then pushes the tool arm to the lower right side of the receiver. The key thing is that it stays put after alignment.

Dan

Unknown said...

Yes I do

Unknown said...

Hello Sir! I am having an issue... the shafts of the 3 rollers are heating too much... can you advise me on something?

Thanks

D. Comeau said...

Hi. Heating in the idler bearings is usually from overtensioning them. One remedy is to loosen the nuts until the there is a very small amount of play in the wheel as it sits on the bolt and then lock them down. Another solution (which I chose) was to make some spacers that fit between the two bearing and contact the inner race only. These spacers will allow you to tighten the nut and not squash the inner races. These spacers need to be quite accurate in length, but there should be no worry about over tightening them. I made some for my large wheel. You can see how I made a spacer here.

Dan

Unknown said...

Thank you for the quick reply!!!

I will try the spacers, I had thought of making them because the bolt needs to be a little tight so the roller is square with the frame and aligned with every roller.

Best Regards from Portugal

Unknown said...

Hi!! Mr I have placed some inner spacers with 5mm plus on each side of the bearrings to be able to tighten the nut and nothing touches the bearing but... I still have the shaft and bearing heating up... next step I will change the tensioner spring (i have 2 car engine valve spring welded together) and if that doesn't solve I will change the ball bearing to roller bearings...

Again, thanks for the help!

Max Headroom said...

Lurking around in the web I found a video of a DIY Neck Knive and I was just hooked so after that I start to look for more and more information about Knive making in general that's lead me to a DIY belt grinder so here I am planning on building my first BG from scarp using a 1 HP 1750 RPM treadmill motor but I have a question in my head, why a 72" long belt?, why not a shorter one instead?. I am in a very tight budget so smaller could be cheaper. Thanks in advance and keep on doing your stuff

D. Comeau said...

Hi Max,

A longer belt will run cooler than a shorter belt. I am not sure why but the 72 inch belt seems to have become the defacto knife making standard. Suppliers offer a variety of useful belts from engineered abrasives to conditioning and polishing belts such as Scotch-brite, leather and cork.
Another advantage of the longer belt is that you can have a larger diameter contact wheel. A 10" diameter wheel can take up a lot of belt, in some designs around 15" or so.

I have used 1" x 30" and a 4" x 36" machines and still find them handy. However, these are chronically under-powered for most metalwork jobs. Note that 4" x 36" has the same surface area as a 2" x 72" and generally cost about the same.

Good luck with your build!

Dan

Unknown said...

I have a question regarding the tube size I bought 2" x 2" with 3/16" wall. and 1.5" x 1.5" with 1/4 wall There is alot of play when one is inserted in the other even without removing the welds on the inside. Is this normal or should I buy some 2" x 2" with a thicker wall say 1/4"?

D. Comeau said...

Hi,

This play is fine. There should be about 1/16" gap of an inch all the way around the tool arm. Keep the weld seam on the same side as the lock down nuts. What's important is that when the tool arm (1.5" piece) is inserted and locked down it's pressed tight into the side of the 2" piece. This position should be consistent and repeatable.

The gap will be the same inside the vertical receiver. Here I used some thin strips of HDPE (plastic) cut from a thin walled container and epoxied them to the face of the tracking/tensioning pillar. Then I applied a bit of graphite to the surfaces. This takes up the play and allow the piece to move up and down on the spring when required.

Dan

Unknown said...

Hello again, I built this grinder and love it. I am having a hard time with alignment. I have put shims under my motor and the Gap on the C pillar is tough. Where do I put the shims on the C pillar and should it be touching the front right or left. The big question is how do you align all of the wheels.

Unknown said...

Thanks for your quick reply earlier I have start the build now that I know the gap is expected thanks again.

Paul T said...

Hi,
I have just started building one of these and so far so good, I'm just waiting for the wheels to arrive from the states and trying to get some pro advice on motor/ speed control set up.
I was just wondering what the 1/8th tube on the side of the vertical tube was for ? I can't find any mention in the text .
thanks,
Paul
(in the UK)

D. Comeau said...

Hi Paul,

The tubing is to add a lever for pushing the tensioning pillar down. If you wanted to add this feature later on it would be good to tack a place to mount a pivot before you paint. I made a retrofitted version here.

Dan

Unknown said...

Can you tell me if the HSS steel for the tool arm can be 0.188 thickness instead of 0.250. My local steel store only have 0.188 in stock, should I have them order the 0.250?

Thanks for all the grinder info, it's priceless! ;-)

D. Comeau said...

Hi Yannick,

The 0.25" wall provides more threads for the bolt to secure the platen plate. However, if you are careful not to over tighten the bolt, the 0.188" wall will work.

Another option is to drill all the way through the tool arm and use a 2" bolt. With this method, the wall thickness doesn't matter much as there is no threading in the hole required.

Dan

Stefan said...

Can’t fint So could you please tell me what size of belts i can use? Thanks

D. Comeau said...

Hi,

Th belt size is 2" wide by 72" long.

Dan

Die-Lon said...

I'm not sure if this was addressed already but what purpose does the bottom horizontal tube serve (labeled B on the diagram)? It appears to just be empty? Also what is the total height of the vertical support from base to the top of the vertical pillar?

D. Comeau said...

Hi Die-Lon,

The lower receiver is to put another tool or attachment such as a work rest or light. I use mine mainly for the adjustable work rest while the top receiver has either the flat platen or the large contact wheel.

The height of part C (vertical receiver) is 10" (same as the two horizontal receivers.) The tracking tensioning pillar is 13" long. With the spring adding to the height, the top of the tracking wheel sits around 16" tall when measured from the base.

I hope this helps.

Dan

Unknown said...

Hi Dan, What is the outside diameter of your tracking wheel? If a different size is used would the length of part G be adjusted to maintain 30 pounds of belt tension? Are you doing the same thing when changing the setup to a different configuration ( example a hollow grind wheel? Thank you and keep posting the great builds. John

D. Comeau said...

Hi,

I have a 2" on the BG-272. The difference between a 2" and a 3" wheel is only 0.5" in height with respect to the frame. Because the tool arm can slide in and out to take up slack, the design need not change if you have a larger wheel, unless of course it's really large. Common 2" & 3" tracking wheels work fine with this design.

I press the tensioning pillar down about 1", slide the tool arm until the belt is tight. Then I lock the tool arm and release the tensioning pillar. My spring seems to not care too much about how far the pillar is depressed, but I've always put about 1" of push on the spring.

Dan

Calvin.Heine said...

just completed mine. thanks for the plans!! hardest part was finding the spring for the tensioner arm and getting it to fit into the base just right to avoid tracking issues!

Toby said...

Dan,
My local steel supplier has the 2x.188 steel, but the 1.5 is only 0.125. Seeing as nothing rides inside the tool arm and pillar ( the 1.5 ) do you see any problem with the thinner tube? It won't twist will it?

Cheers,
Toby

D. Comeau said...

Hi Toby,

I recommend 0.25" wall soley for tapping the threads through. Many have made grinders with 0.125" wall for the tool arm and tensioning/tracking pillar. Simply drill though the tool arm and put the bolts through to secure the platen plate.

Dan

Unknown said...

Dan, The Mechanical Bill of Materials drawing shows a 1.25 inch offset for the tracking hinge but the website drawing shows and says a 1.125 inch offset for the tracking hinge. I'm not sure it is matters but is one better than the other? Thank you for all your work, John

D. Comeau said...

Hi John,

You are correct in that there is a slight mismatch in my numbers. On my machine, the centre of the hinge bolt is 1-1/8" from the right side of the tracking hinge, Having it in 1-1/4" would give slightly more +/- camber on the tracking wheel axle which may be beneficial for those builds that need the extra camber to bring the belt in line. I will update to match. Thanks!

Dan

Unknown said...

Hi Dan,

I built one of your grinders here and I really love it. I am grinding my own bevels now and will send my first batch of blades off for heat treat this week. In many ways the grinder worked with very little messing around getting my tracking lined up.

I think I spent the most time getting the play out of the pillar. It seems like every once in a while something wiggles around there and my alignment changes. I think I may weld a strip on and grind until things are tight enough. I suppose if I built another one I would use square receiver stock for the frame and hopefully avoid the fiddling around trying to take play out of the set up.
Thank you for this blog.
Randy

D. Comeau said...

I shimmed mine with some plastic strips cut from a jug. Some guys tack some thin gauge steel on the pillar. As long as it can't twist in the receiver you should be ok. The tension of the belt should keep it firmly in place when it's running.

Stefan said...

Hi would like to ask you how I can post picture of my buil and also ask some questions
Please?
Thanks

D. Comeau said...

Hi,

Drop me an email at knives at dcknives.com

Dan

Stefan said...

Hope you did get my mail :-)

Unknown said...

Im working on my belt sander per plans. Everything goes ok. Grat design, easy building. I will post when finished!

Unknown said...

I know this an old page at this point, was wondering if you have any tips for working out alignment issues. Pretty sure I've got them, the tracking is really touchy and the belt rides off the idlers easily. I know that's a HUGELY vague question just looking for general advice.

D. Comeau said...

Hi,

First and most important is the alignment of the motor. The motor shaft must be very close to 90° angle from the belt path or the belts will walk off the wheels. What I did was kept the motor mounting fasteners loose, all but one. Then put the belt on and started the grinder. I nudged the motor slightly to the front and back to see how this affected the belt path. Once I found the sweet spot, I stopped the motor and tightened down the motor.

You should check that the wheels are all in line. I did this with a yard stick. The right side of all the wheels needs to be very close to the same plate. Place the yardstick on the motor's drive wheel and then across to the top and bottom idler wheels on the platen. Then repeat from the tracking wheel to the platen idlers. If you have the wheels spaced off the frame or platen plate the same distance, this shouldn't be an issue.

If you want to send me some pics or a short video where I can see all the wheels while it's running I can likely pin-point the issue. Send to knives at dcknives dot com.

Dan

Unknown said...

I just wanted to thank you for providing grinder plans and this blog, half way building my grinder and cannot wait to start it up.

stevediaman said...

Just finished building mine thanks to your awesome plans but I have a question regarding reversing the belt direction. the belt shifts on the platen to the right quarter to half an inch any ideas why and how to fix this. I'm guessing I have something out of alignment but I've tried everything. using a 2 pole 2hp motor with a vfd and aluminum wheels with the drive and tracking wheels crowned.

D. Comeau said...

Hi Steve,

Usually the motor alignment is the culprit. If you can loosen the motor mounting bolts, all but one, and nudge the motor a half a degree when looking from the top. If this action makes it worse, then go the other way. Having two crowned wheels offers better tracking, it is also more difficult to calibrate.
Let me know how it goes. Also, if you wanted to send a short vid to knives at dcknives.com I can take a look and possibly offer something else for a solution.

Dan

Toby said...

Hi Dan,
I built a grinder using your guide here. Having trouble with the belt tracking: the belt wobbles left and right about 1/8".

All wheels are lined up using a laser so it's not alignment, but I can't figure out what the problem is. Any tips?

Cheers,
Toby

D. Comeau said...

Hi Toby,

Belt wobble (lateral movement) is almost always caused by low belt tension or misaligned crowns. The first thing I would to is loosen all but one motor mounting bolt, then nudge the motor when the grinder is running. If you look down on the motor from above, nudge the motor a tiny bit clockwise, like 1/2 a degree. One of two things should happen; the wobble gets better or the wobble gets worse. You can deduce the solution. One the wobble is gone or minimum, be sure to lock the remaining motor mounting bolts down.

The wheel faces can line up near perfectly, but that's only part of the equation. It's likely that your drive wheel and the tracking wheel are crowned. The motor shaft and the tracking wheel axle need to be parallel. This is where nudging the motor can help.

If you can't get any joy from a nudge, please send me a couple of pics or a short video in the unit running to knives @ dcknives.com.

Dan

Unknown said...

Hey Dan,
Thank you for the plans and the years of replying to comments, ill be finishing up a build based on this tomorrow!
Had a good read tonight and the replies to comments answered any questions i could have had, just wanted to say thanks!

D. Comeau said...

Hope your build turns out well!

Dan

Unknown said...

Man, I greatly appreciate your blog; I have read it in total tonight and gained quite some knowledge. I purchased a copy of your build and it has had tracking issues I haven't been able to overcome. I should say the specific problem is the belt wont center over the platen and zips over it from left to right or vise versa. Tonight I have learned to check wheel alignment with a weighted string and straight edge,that the spring may not have been strong enough, and the motor may be misalignment. I have found a five inch spring that may be stronger, is 5" within tolerance? Is there a sure way to know if the motor is positioned well, or is it just trial and error? I am using a sheave/shaft system. I have been messing with it for days now. Is there anything else I can look at? Any information would be appreciated greatly.

D. Comeau said...

Hi,

What you are seeing, the fast wobble from side-to-side, is usually due to motor/drive wheel alignment. Belt wobble is made worse under low belt tension. Aim for 30 to 40 lbs force on the belt. You can check your spring. Simply put your spring on a bathroom scale and press down until the spring compresses about one inch. If the scale reads between 30 and 40 lbs, this should be fine. Length of the spring generally isn't a problem. 3 to 5 inches should be fine.

If you could send me some pictures or a short video of the grinder running that includes the tracking wheel and drive wheel, I can usually work up a plan to sort the wobbles out. My email is knives at dcknives.com

Dan

Ed and Lori G said...

Just a big thanks for your detailed plans, I used them to make a 2x72 sander. I used a 1750 rpm motor with a jack shaft and a 3.5 and 5.75 pulley to a 5" drive wheel. most of the other item are similar. It works great I am just waiting for some key material so I can then put a key in the shaft. Don't want to work it too hard till I have the proper shafting.

Handle_Fishsticks said...

Hi dan.! Thanks again for your guidem. I have a tracking issue and my belt flings off when starting. I am using two of these compression springs (https://www.homedepot.com/p/Everbilt-11-16-in-x-1-1-4-in-and-7-8-in-x-4-in-Zinc-Plated-Compression-Spring-4-Pack-16084/202045472). I am guessing these are too weak? My alignment seems fine.

D. Comeau said...

Hi,

Not sure about the spring you are using. Not rate mentioned on the web page from HD. I have used this one from a storm door kit https://www.homedepot.com/p/Barton-Kramer-Storm-Door-Crash-Chain-7/205929788 It's around 30 lbs force.

Normally a weak spring will cause belt wobble, and erratic movement under load, but shouldn't just go flying off. I'd suspect one wheel is out of kilter a bit. If you want to send me a couple of pics (especially looking from above) to my email I may be able to help. My email is knives at dcknives.com.

Dan

Unknown said...

I have extra springs if anyone wants one, had to buy 5 when purchased. Will mail out free of charge. Jim

taffytikka308 said...

Hi Dan, I am in the process of building a grinder and have question. What is the purpose of the 1/8 pipe shown on the right side drawing of the frame.
Cheers,
Phil.

D. Comeau said...

Hi Phil,

The pipe is used to make a hinge for a belt release lever. Some find it difficult to reach over the grinder and press the tensioning pillar down. It's much nicer to have the pipe in place before painting the frame. You can see how I retrofitted mine after the fact here.

Dan

Unknown said...

I just want to say "THANK YOU" for making your site and this page. I have learned tons of info and built my own grinder from your prints on this page. I can't tell you how much time you saved me being able to see how it was build along with all your tips and detailed build comments. This is by far the best site I seen anywhere. THANK YOU AGAIN AND AGAIN !!!!!!! MUCH APPRECIATED !!! - Steve

D. Comeau said...

Hey Steve,

Thanks for your kind words. Happy grinding!

Dan

James Harper said...

I found that a 1/2" copper tube, Type L, works well for the wheel spacers. The thickness of the tube matches up well with the inner race of the bearings on Origin's lightning wheels. You just have to make sure your cuts for the spacers are square, or spend some time grinding them down ensure they will sit flush against the wheel.

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