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Y-geo,
I know what mean about getting magnet polarity in the correct N-S pointing direction. I have similar Hall Effect tachometers on two of my 12" and 7" swing lathes (see Homemade Metal Lathe Digital Tachometer - HomemadeTools.net and http://www.homemadetools.net/forum/m...3147#post15859 .
The eBay sellers luckily provided the wiring schematics at the auction website pages so no need for a translation. Also Randy Richard in the Shop (see his YouTube channel ( https://www.youtube.com/channel/UCme...AeH21q-xcNwdfw ) warned about getting magnet N-S orientation set correctly before gluing in place. Otherwise the Hall Effect sensors won't work at all.
Thanks,
Paul Jones
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Paul,
both things I considered , the mounting on the gear box guard worried me about any hamfistedness on my part wrecking it during a gear change.
The biggest contributing factors of my choice was the location of the speed controller and the double switch. I would have liked the tacho display at the top front but the speed box is quite a lump (found a spare on ebay cheap ) so may look to strip it out of its OEM box and modify it to put the speed pot on top BUT have the rest of the gubbins else where ie bottom some place with good fan air movement over it. Who knows what i will get up to .......................
Thank you for the links duly filed as i may just alter the placement of the magnet as I would like to put a spider in place for my rifle barrel work at some point.
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Y-geo,
Good information and thanks.
I am about 90% complete on completing a lathe spider project for mounting at the rear of the 12" swing lathe headstock spindle. The spider will be a permanent installation and it does include a 6 mm cross drilled hole for an even smaller neodymium magnet to work with the Hall Effect tachometer sensor. I just have to make the four brass screws with knurled and cross-drilled heads and the project will be finished. I don't do riffle barrel work but work a lot with 3/8" and 1/2" diameter 303 stainless steel rods and the spider plus and external rest support keeps the rods from dangerously whipping around at high RPMs.
The reason I put the tachometer on the 12" swing lathe was because I had intended to use a variable frequency drive (VFD) to power the lathe but never got around to doing this. The geared head lathe selection of twelve speeds from 70 to 1220 RPM is more than enough and the VFD would be nice but not necessary. However, I wish I had a 3 HP instead of a 1.5 HP motor for making deeper cuts with carbide inserts.
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Paul,
i had the brass screws from another Job so, that is a start :-) although to be fair they are slot heads so your knurled bolts seems like it could well happen Lolz
i am off tomorrow (today is a holiday ) to a friends house to use his lathe/mill to get the kinks out of a very rough base casting on my newly modded drill press and to make up some alloy T nuts for it.
My whinging about high pressure grease supply here in the UK just got me a message from a Bel Ray supplier in the UK who can supply the red termalene grease i used to use when i was working stateside and in the west indies . So thank to the forum I can get some and i will a write up / follow up when i do my headstock tear down with comments for those of us stuck across the pond
thank you guys, & Paul good luck with the quest for a 3HP motor.......................
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A short strong spring between two washers on the clamping bolt under the tailstock will keep the nut under tension and help release the clamping plate.