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Post by dave632 on Jun 26, 2014 14:15:08 GMT -7
Anybody know where to get a decent magnetic field tester that is not priced out of sight?
Also looking for a balancing rig and a tool to hold an armature for rewinding. |
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Post by pceng on Jun 26, 2014 14:38:12 GMT -7
Hey Dave , You might already have one......... piece of glass & metal filings....... works for me , when needed.......
........ Peter
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Post by TGM2054 on Jun 26, 2014 15:06:39 GMT -7
I've used a compass and a piece of graph paper. Set the compass at the top of the paper, determine whether the maganet is a north or south, then number them. Set the magnet at the bottom of the paper and start to slide it up, when it starts to move the needle on the compass mark the paper with that magnets number. Then match up your magnets according to where they are on the paper. It's kind of crude but it works.
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Post by jjwallace on Jun 26, 2014 16:42:27 GMT -7
Anybody know where to get a decent magnetic field tester that is not priced out of sight?
Also looking for a balancing rig and a tool to hold an armature for rewinding. Dave this is how I've been testing magnets for awhile now. nitroslots.com/thread/1059/magnet-strength-tester-cheap I have no plan on changing because it seems to work very well. It will give you a relative number that you can match up. Don't know if you have a Harbor Freight close by , but the last time I was in one they still had these....cheap. I use mine for weighing cars, mail, etc. as well as magnets. Also check out Eagle's Blacktop Raceway thread. Somewhere in there I think he explains how he uses 2 neo dots mounted on a lathe to balance motors. The same thing can be accomplished with a vise instead of a lathe. Hope this helps. Jeff |
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Post by pceng on Jun 26, 2014 19:24:10 GMT -7
Hey guys , Think what your talking about are different ways of matching magnets........... strenght & field are different....... not sure what Dave , is looking for.
Not long ago we talked about BSRT 290 & 277 magnets....... think somebody pointed out they were the same strenght wise , but the 277's had a larger field (due to them being taller)
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Post by jjwallace on Jun 26, 2014 19:42:07 GMT -7
Just thought this might help.
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Post by pceng on Jun 26, 2014 19:52:18 GMT -7
Just thought this might help. Never thought different ......... just made me wonder what was being looked for........ |
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Post by dave632 on Jul 19, 2014 22:57:30 GMT -7
Thanks for the reply,s. I was looking for a way to test magnet strength. I will give these methods a try.
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Post by dave632 on Jul 20, 2014 15:26:10 GMT -7
Built one from a scale I already had. Works pretty well.
Old T jet magnets are real weak sisters, another word is junk, lucky to get a 1 gram reading out of most of them and a few could not pull one gram. Regular AFX from 2-5 and Super II read 6-7.
As a comparison a single Neodymium 10mm magnet had a 55 gram pull.
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Post by pceng on Jul 20, 2014 18:16:54 GMT -7
Anything that can help measure strenght as to differentiate & match is probably good enough........ a bolt with a stack of washers is better than nothing.
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Post by dave632 on Jul 25, 2014 13:55:54 GMT -7
I just tested a couple of Neodymium magnets on my home made tester and they measured 360 grams, (3/4 lb.) of pull vs a pair of stock T jets at 2. That was with about a 1/4 inch of space from the magnet and the scale. These were approximately 1 1/4 inches in diameter and they will really bite you if you put a finger in between them and let them snap together.
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