tag:blogger.com,1999:blog-3678387596306127065.comments2017-02-21T14:37:52.199-07:00DIY Knifemaker's Info CenterD. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comBlogger762125tag:blogger.com,1999:blog-3678387596306127065.post-91314340825081037732017-02-17T09:58:31.511-07:002017-02-17T09:58:31.511-07:00Hi Bradley,
I intended the total watts to be arou...Hi Bradley,<br /><br />I intended the total watts to be around 2200. At 120 Volts that would require current of 2100/120 = 18.3 A. 120 V divided by 18.3 A = 6.55 Ohms. With 18 gauge wire I could use three elements in parallel to get close to this. Adding elements in parallel lowers the resistance. I used the formula Rtotal = 1/(1/R1)+(1/R2)+(1/R3) where R1, R2 and R3 are close to 19 ohms. This gives us close to 6.5 ohms. <br /><br />Hope this helps.<br /><br />Dan<br /> D. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-48181442346527280262017-02-16T23:27:27.890-07:002017-02-16T23:27:27.890-07:00How did you come you with needing 19 ohms for your...How did you come you with needing 19 ohms for your elements?Bradley Howeshttp://www.blogger.com/profile/14439810742008714416noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-69289505526913263042017-02-16T21:47:37.785-07:002017-02-16T21:47:37.785-07:00Thanks for all of your help Dan. I'm trying to...Thanks for all of your help Dan. I'm trying to design a 240v element for the same furnace dimensions from my earlier post of 4.5" x 6.5" x6.5", which i come up with a total of 1.4 sqft. I'm struggling with the kanthal handbook that you had linked to before. To quote you:<br /><br />"On page 6, the curve shown for (a) indicates around 2800 Watts per square foot of wall to reach 2110°F (1100°C)."<br /><br />Ok, this is where i'm stuck, well, for starters anyway. If that is how the chart on page 6 is to be interpreted, it defies common sense. To follow your example and referring to the chart, we'd need over 4600w per square foot of wall to reach only 1470F. ???<br /><br />Common sense tells us that if you want hotter temps, you need more power, not the inverse. <br /><br /> Honestly i feel they have the wattage and square footage flip-flopped. This chart would make a lot more sense if the column on the right was square feet per kilowatt, not kilowatts per square foot. Maybe i'm just confused. <br /><br />I'm also find the element surface load chart confusing also. If i understand it correctly, the surface load is simply the wattage in relation to the amount of surface area of the element wire. Once again, my logic has it that in order to see higher temps, i'd need more wattage across the wire, not less, as their chart indicates. Their recommended maximum surface load for 2000F is 19W/square inch, while 1470F is 32W. Less where you really need it, and less where you don't. Honestly though, i do think i understand why. <br /><br /> Please correct my math if this is incorrect. To calculate the surface area of a wire, you should multiply the diameter by pi, then multiply that by it's length. 18ga for example:<br />.040" x pi = .125 square inches. Multiply this by 12" and it gives us 1.5 square inches of surface area per foot of 18ga wire. <br /><br />So let's apply this to the 2000w 120v element configuration that you had recommend i try to get to copper melting temps, which i thought sounded just about right to me. <br /><br />"18 AWG Kanthal A-1. Shoot for around 7 ohms @ 120 V (~2000 W)"<br /><br /> For a 7 ohm we'd need 12.9 feet of 18ga wire. At 1.5 square inches of surface area per foot, that gives us a total surface area of 19.4 square inches. <br /><br />At 2000w, the element would have a surface load of 102w/sq in. <br /><br />That's over 5 times their recommended maximum load of their chart. Maybe i suck at math. Maybe their charts do. <br /><br /> What gives?<br /><br /> Thanks. Blaine. Blaine Taylorhttp://www.blogger.com/profile/14526070342818385206noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-77148093841187631542017-02-16T20:15:41.428-07:002017-02-16T20:15:41.428-07:00Kev,
It looks pretty good. The motor is a decent ...Kev,<br /><br />It looks pretty good. The motor is a decent horsepower. The build quality looks good from what I can see in the photos. Give it a spin. See how the belt tracks. Push some steel into it and see how it performs. <br /><br />DanD. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-61301489959217021272017-02-16T12:23:55.778-07:002017-02-16T12:23:55.778-07:00Hey Dan,
I'm a hug fan and have been lurking ...Hey Dan,<br /><br />I'm a hug fan and have been lurking your site for some time now, however, I recently found a post on Craigslist for a belt grinder I am very interested in.<br /><br />I took the time to compare/contrast it to the builds you have posted on your site, however, I would really like a professional opinion on the pictures before I go in to talk to the seller. <br /><br />https://losangeles.craigslist.org/lgb/tls/6001785483.html<br /><br />Any input would be greatly appreciate, thanks for your time!<br /><br />- KevKevin Junghttp://www.blogger.com/profile/10578427600949595430noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-48382754318745943032017-02-15T17:20:48.967-07:002017-02-15T17:20:48.967-07:00Yes, having the tracking wheel crowned is importan...Yes, having the tracking wheel crowned is important as the belt which is flat tries to position itself to the center of the wheel as that is the largest diameter. This improves belt stability. <br /><br />DanD. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-36750470502099352712017-02-15T01:56:22.725-07:002017-02-15T01:56:22.725-07:00thankyou somuch, my only question is the belt adju...thankyou somuch, my only question is the belt adjusting wheel has a slight angle on its surface... is this nessessary, new to machiening and im doing it all from scratch cant figure out how i will do this on my new roller im making Typos TranscENDhttp://www.blogger.com/profile/12350039005279319669noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-75017698874816383222017-02-14T01:55:47.417-07:002017-02-14T01:55:47.417-07:00good postgood post<strong><a href="http://www.bigbangdissertation.com/">bigbang dissertation writing</a></strong>http://www.blogger.com/profile/07349555226330578834noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-36846810426832920402017-02-11T17:06:34.574-07:002017-02-11T17:06:34.574-07:00Any chance you have video of this in action? I'...Any chance you have video of this in action? I'm just about finished mine, missing a few things and waiting on motor. Thanks for all the info! Love when skill and knowledge are willing shared.Unknownhttp://www.blogger.com/profile/01841764476586005649noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-49379494064063414792017-02-11T05:55:54.635-07:002017-02-11T05:55:54.635-07:00Hi Dan, Thank you for sharing this tutorial. It is...Hi Dan, Thank you for sharing this tutorial. It is a great help, building my own grinder. But I have a problem translating a part of the text into Dutch, at least i don't understand what you mean by: "I put a backing piece of 1/4" plate behind the angle to step it away from the plate. This way the wheels and belt can be away from the plate a safe distance." <br />Maybe it is possible to post some pictures that make claere what you are trying to tell? <br />thank you<br />regards<br />Arie de VriesArie sr de Vrieshttp://www.blogger.com/profile/16505815829365656822noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-43047893579619529052017-02-10T13:02:59.302-07:002017-02-10T13:02:59.302-07:00I have downloaded the CAD file for the wheels. Sad...I have downloaded the CAD file for the wheels. Saddly the only parts in 3D are the bearings. The whole rest is only available in 2D. Could you send me a propper CAD file of the wheels?Pjotre Tonofskihttp://www.blogger.com/profile/03219900854208407781noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-21083247322862296062017-02-10T12:47:53.336-07:002017-02-10T12:47:53.336-07:00I built a pair of burners based on your design. I...I built a pair of burners based on your design. I made the mistake of porting the flare end of the 3/4" tubing and the 1" stainless. The end result was unable to sustain a good burn and had the flame front sitting just inside the 3/4 tubing. I did an experiment running the burner flare tube backwards ( 3/4" to 1 1/2" reducer as the flare end and it had a great flame. I had to go back and square off the ends of the 3/4 and port the 1" stainless quite a bit to get a consistent good flame. My plan is to flare out the stainless further with some hammerwork once my anvil arrives. I think the hard transition from the 3/4" to the 1" stainless creates a turbulent front which stops flame propogation and keeps a good flame front.<br />TrentOhttp://www.blogger.com/profile/12474524876867557515noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-660887541380031892017-02-09T19:37:25.869-07:002017-02-09T19:37:25.869-07:00I wealth of info on current vs temperature.
http...I wealth of info on current vs temperature. <br /><br />https://en.m.wikipedia.org/wiki/NichromeBlaine Taylorhttp://www.blogger.com/profile/14526070342818385206noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-26806478341335730272017-02-09T19:35:30.142-07:002017-02-09T19:35:30.142-07:00The spring I used was close to the inside dimensio...The spring I used was close to the inside dimensions of the tubing. I just dropped the spring in and put the tracking pillar down to press on it. Note the bottom of the tracking pillar has a welded flat. Otherwise the spring might go inside of it. <br /><br />DanD. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-77894655319010120032017-02-09T11:22:57.578-07:002017-02-09T11:22:57.578-07:00Hi i was wondering how did u put the spring inside...Hi i was wondering how did u put the spring inside the tube.just dropped it in or some extra support.sry for bad eng, hope u can understand me:=)Egerthttp://www.blogger.com/profile/05777731613414824005noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-83115524340830046652017-02-07T17:47:34.371-07:002017-02-07T17:47:34.371-07:00Hi Paul,
I used some strips from an oil jug. They...Hi Paul,<br /><br />I used some strips from an oil jug. They are about 0.5 mm thick HDPE and about 200 mm long. I put them on the right and rear faces of the pillar. This provides some sliding action but limits the slop. <br /><br />As long as it doesn't move when the belt is under tension you should be good. <br /><br />DanD. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-44155784746855862912017-02-07T14:50:21.872-07:002017-02-07T14:50:21.872-07:00Hi Dan,
Just finished building my grinder followin...Hi Dan,<br />Just finished building my grinder following your excellent article. All works but having problems getting rid of the slop in the vertical sliding pillar even though packed out. I guess I need to pack more until it still slides but has no lateral movement.<br />Thank you for sharing your ideas.<br />Paul (UK) Paul Gardnerhttp://www.blogger.com/profile/01478953847901321996noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-76250028610259579592017-02-06T16:21:15.786-07:002017-02-06T16:21:15.786-07:00Awesome knife templates. I noticed you have a HT1 ...Awesome knife templates. I noticed you have a HT1 and HT3 knife designs but I can't find HT2. Is there an HT2 design?Unknownhttp://www.blogger.com/profile/14024632467491770325noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-73460382422219202812017-02-05T18:05:49.202-07:002017-02-05T18:05:49.202-07:0018 AWG Kanthal A-1. Shoot for around 7 ohms @ 120 ...18 AWG Kanthal A-1. Shoot for around 7 ohms @ 120 V (~2000 W). A well sealed furnace with K firebrick at that small volume will get to copper melting temps. <br /><br />Dan D. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-31857245490256788242017-02-05T08:27:20.385-07:002017-02-05T08:27:20.385-07:00Another example of amps vs temp. I'm using a 1...<br /><br />Another example of amps vs temp. I'm using a 16 gauge cord to power my 2400W furnace. This is a cord from a typical 1500W space heater. It doesn't even get warm to the touch at 2400W. <br /><br /> The starter draw on my V-8 truck is right around 200A. At 12V, that's 2400W also. If i tried using the 16 gauge cord as the starter cable on my truck, it would become really hot really quick and melt. Was this melting temperature a result of 2400W of power? Nope. It was the 200 amps trying to pass through it. <br /><br />It's the amperage that that has more to do with what temperature range you'll be in that what the wattage does. The wattage just needs to be great enough to overcome the load of the furnace size and insulating factors. Any wattage over that point will just get things up to temp faster. <br /><br />Sure, there are a lot of variables in play here, but i feel amps vs temp for a given wire size is the bases on where to start. <br /><br /> So my question still stands on what a "suitable wire size" is for kanthal A-1. <br /><br />At this point i feel that trying to reach high temps with 120V and stay within the recommended 80% operating range of a 20A breaker, i'd need to go with 18 gauge or smaller. <br />I suppose i'll need to spend some time and money and do my own research. <br /><br />Thanks again Dan. <br /> Blaine. Blaine Taylorhttp://www.blogger.com/profile/14526070342818385206noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-29621406903551250382017-02-01T22:57:42.637-07:002017-02-01T22:57:42.637-07:00Hi Blaine,
I don't understand the author'...Hi Blaine, <br /><br />I don't understand the author's concept with respect to temperature and current. It's Watts that equate to energy. A large current at 2 V is not a lot of Watts if you get what I mean. If you wanted to use the wire act as a fuse, then this table is helpful. You will know at what current the wire exceeds it thermal capacity and burns up. I think you found this out already. ;-) <br /><br /><br />But there are a few other factors to look at. For example heating a wire in a poorly insulated, say regular masonry brick, or leaky environment will never reach intended temperatures. This is because the loading will always suck heat away from the coil and not contain it. This is called "loading."<br /><br />The PDF I was looking for was no longer on Kanthal's web site, but I found it at Hi-temp's site. <a href="http://www.hi-tempproducts.com/pdf/the-kanthal-furnace-mini-handbook.pdf" rel="nofollow">http://www.hi-tempproducts.com/pdf/the-kanthal-furnace-mini-handbook.pdf</a> Although they don't reference temperature per Amperes, for reasons I mentioned above, they do have a furnace wall loading chart. This is what is of interest to us. Units are in Watts (not Amperes). On page 6, the curve shown for (a) indicates around 2800 Watts per square foot of wall to reach 2110°F (1100°C). Take your interior wall dimensions and determine what the square footage is. In your case, you are looking at about 0.7 square feet. <br /><br />2800 Watts per square foot * 0.7 sq. ft. = 1960 Watts. (If you want faster heating times, crank up the 2800 W/ft2 to 3000 or more.)<br /><br />To get 1960 Watts from some Kanthal we need to know the voltage supply. So we take 1960 Watts and divide by the Voltage to get Amperes. <br /><br />1960 W / 120 V = 16.33 Amperes. <br /><br />With the desired Amperes we can find the Ohms. <br /><br />Ohms is 120 V /16.33 A = 7.34 Ohms.<br /><br />Use the resistance per foot of Kanthal A1 for a suitable gauge to determine the length of wire needed to make 7.34 Ohms. <br /><br />For 240 V circuits (2 times the Voltage), use two times the Ohms 14.7 ohms. <br /><br />If you are concerned about the total current through a single coil, split the current into two or more parallel coils will create the Watts you need without the high Amperes in any one coil that will cause your coil to be a fuse. :-)<br /><br />I hope this helps.<br /><br />Cheers,<br /><br />Dan<br /><br /> D. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-41027383776984214082017-02-01T21:51:51.441-07:002017-02-01T21:51:51.441-07:00I used a wire feed welder with flux core wire.
Da...I used a wire feed welder with flux core wire.<br /><br />DanD. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-64048884780688978932017-02-01T10:51:04.669-07:002017-02-01T10:51:04.669-07:00 Sorry I just have one last question how did you ... Sorry I just have one last question how did you weld the piece together? What process did you use?<br />Seppo Suhonenhttp://www.blogger.com/profile/14889503776225634323noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-22810592011994506652017-01-31T23:57:20.441-07:002017-01-31T23:57:20.441-07:00Thanks Dan for the quick reply. The link you provi...Thanks Dan for the quick reply. The link you provided doesn't contain any info on A1. I have seen their furnace handbook but i didn't see anything in it concerning temperature vs amperage. If you'll look at the first table of this link for nichrome wire and we used your example of 22 amps through 12 gauge but used nichrome wire, the temperature would be less than 1000f, and the chart shows that 12 gauge nichrome would require over 30 amps to get hot enough to melt aluminum, or that 15 amps through 24 gauge nichrome would melt it. I'm looking for this type of information on kanthal A1. <br /><br />http://cecs.wright.edu/balloon/images/2/22/Nichrome_Wire_Heating_Element_Design_Basics.pdf<br /><br /> Thanks, Blaine. <br />Blaine Taylorhttp://www.blogger.com/profile/14526070342818385206noreply@blogger.comtag:blogger.com,1999:blog-3678387596306127065.post-67102410086283654732017-01-31T20:38:15.946-07:002017-01-31T20:38:15.946-07:00Hi Blaine,
Kanthal A1 is rated for 1400°C (2552°...Hi Blaine, <br /><br />Kanthal A1 is rated for 1400°C (2552°F) and so should be able to withstand the temperatures required to melt copper. In fact I regularly take my heat treat oven to 1080°C (1975°F) with Kanthal A1 running @2000 Watts. <br /><br />This is Kanthal's handbook for the product. <a href="http://www.kanthal.com/Global/Downloads/Furnace%20products%20and%20heating%20systems/Heating%20elements/MoSi2%20heating%20elements/S-KA058-B-ENG-2012-01.pdf" rel="nofollow">http://www.kanthal.com/Global/Downloads/Furnace%20products%20and%20heating%20systems/Heating%20elements/MoSi2%20heating%20elements/S-KA058-B-ENG-2012-01.pdf</a>. <br /><br />You will need to get your watts up if the loading is significant. I don't know what the firebrick is and the size the crucible. I don't think pulling 22 A through some 12 gauge wire would be a problem. <br /><br />The fastest way to melt copper is with a gas setup, but there may be reasons for going electric such as CO emissions. <br /><br />Good luck!<br />DanD. Comeauhttp://www.blogger.com/profile/03691351359902143885noreply@blogger.com