Glad I could help that’s what we’re here for. Not to hijack but doing a 9 spacer grind test worked good for me to map the chuck out on the machine. Surprisingly I had a .0003 difference in blocks. Concaved to the center of chuck. Haven’t reground top of chuck till a plan comes together. Happy grinding
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Mag Chuck Restoration Questions
- Thread starter Robo_Pi
- Start date
I have not done any block tests, but it is likely a very good idea. When we grind the entire chuck surface, considerable wear of the wheel takes place, even with light cuts, as well as the smaller amount of total chuck surface removal. That definitely changes the geometry somewhat. With the test blocks, very little wheel wear takes place if it is done properly. Concave seems unusual, would expect convex. Perhaps the ways of the grinder have been reconditioned, and they worked them concave a bit to make the job last longer until it goes concave (but that much concave would probably be a mistake,) (Edit: Oops, on reading this again I think you are talking about the block pattern being concave in the middle, not the chuck(?)) Or, maybe things just moved and settled over time. Not knowing the history of the grinder and it's use and maintenance, many things become a mystery and a guess...
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You guys are getting way ahead of me. Right now I'm just looking at rebuilding the mag chuck. It's going to be quite some time before I actually buy a surface grinder to rebuild. Although I'm currently looking at this one for $200. It's also a Taft-Pierce, so it will match up with this Taft-Pierce mag chuck real nice.
The only problem with this one is that it's about 600 miles from me. I can probably find something similar closer by.
The only problem with this one is that it's about 600 miles from me. I can probably find something similar closer by.
When doing my block test I made 9 1” solid spacers about 1/2” thick. Ground them all together bunch up both sides got all spacers to the same thickness. Then placed one in each corner and a cross pattern so three rows of 3. Then with wheel dressed already dust the tops until all 9 are cleaned up. My center spacer was the thickest. Then the spacer closest to the operator center and right were next thickest. All three were a different reading. The other six throughout were the same. My .0003 difference we’re between those 3. Which were all thicker than the 6 telling me the center and toward operator and right were lower. Which coincides with positioning of parts on and off over time would wear from dragging parts. Trying to be as observant as possible.
So that was before grinding your chuck(?) That is exactly what you would expect to find on a used chuck, users tend to put all the work in the middle of the chuck instead of using the entire chuck evenly. My B&S mag chuck was about .002" low in the center and toward the operator before grinding it in. The test blocks are even more useful while grinding in the chuck, showing deviation from even readings, mostly from wheel wear. The blocks will not show curvature of the chuck from sag as the table traverses, making the center high. Neither will a test indicator mounted on the spindle housing measuring the chuck. A perfect curve as the table drops off in both X directions will show up as zero movement on the indicator, even thought the chuck is convex from left to right, a common situation, and essentially the same with milling machines, caused by overhangs at the end of the travel. The cure is to test the bed ways and the table ways for being flat and parallel, using a known to be flat surface plate and a known to be flat camelback straightedge, and make everything flat and square to the machine's reference surfaces.
I found another mag chuck rebuild video. This is guy just milled the surface too. I think the idea is that you can always regrind the surface on the surface grinder that you end up using the mag chuck on.
Clearly this is just a hobby restoration in this video. Which is what I'm intending to do. The idea is to gain some experience, not necessarily create the most precise mag chuck ever.
Clearly this is just a hobby restoration in this video. Which is what I'm intending to do. The idea is to gain some experience, not necessarily create the most precise mag chuck ever.
What I meant about milling the top surface of the mag chuck is. If you were to use the chuck on the mill with a milled surface finish on it you will loose magnetic pull “holding power” of the chuck by just the lines by the cutter. For the holding strength to be optimal you need a smooth flat surface, and on a mill youd need a lot of it. If your thinking of using on a mill.
A Taft pierce is consider on the higher end of grinders. If condition is good that’s a solid grinder. 600 miles idk about that.
A Taft pierce is consider on the higher end of grinders. If condition is good that’s a solid grinder. 600 miles idk about that.
That's a good point. I was thinking of buying this chuck mail-order and because of this I'm not really in a position to go look at it first. I've been looking at these Taft-Peirce mag chucks and it's pretty hard to find one for under $300 in a shape that basically looks like the one in this photo. So I'm thinking it might be worth a shot.
Although I just discovered that this place is a lot closer to me than what I had first thought. Apparently it's just under 200 miles away. That's not too bad. I could go visit this place in person. It's called HGR Industrial Surplus in Euclid OH. I live in Western Pennsylvania. So it's not as far as I thought. For some reason I was originally thinking this was way out west. I don't know where I got that idea. Maybe I confused them with other places I was looking.
They have three things I'm basically interested in:
The Taft Peirce mag chuck I pictured in the OP. It's actually only $69 if I go pick it up.
The Taft Peice Surface Grinder. I think they are asking $235 for that one, no mag chuck on it. I don't even know if it runs, but I'm expecting to completely rebuild it from scratch, including milling a scraping the ways. I'll probably also need to find a motor for it because I think the motor it has on it is 3 phase and I don't have three phase.
They also have a South Bend Lathe and a RoundTower vertical mill I'm interested in.
The South Bend Lathe - $1,119 - no tooling save for the large 12" 4-jaw chuck
RoundTower Vertical Mill - $895
If I can get these all on my 16' flatbed trailer I could make one trip and grab them all for about $2,500.
That'll keep me busy rebuilding these old clunkers for the rest of my life.
I like these old machines. I used to be a machinist about 50 years ago. And these were the kinds of machines I used. Although the mill was a Bridgeport.
The South Bend lathe is a little on the large size, but I'm really looking at the prices more than anything. I can deal with it being this large. But in truth I'd rather have a shorter one, and it would be nice if it came with a taper attachment and a few more accessories. I have seen smaller one's around at similar prices, but again, usually quite far away.
I'm in no hurry. I wouldn't be picking these up until summer anyway. These specific machines will probably be gone by then. So I'll have to wait until they get something else in at the right prices. $2500 is about the max I want to spend. But at the same time I want to get the max number of machines for the buck. And I'd really like to have a large lathe, vertical mill, and surface grinder. So the package deal I've outlined above would be pretty close to what I want, and what I want to pay. The fact that these would all be at the same location and so I could potentially pick them all up in one trip which would be icing on the cake.
Ok, don't mind me. I'm just a little hobbyist with BIG dreams.
But I do have an empty 16' flatbed trailer. So who knows? I have these all on my "watch list" with HGR. They are always getting new stuff in too so who knows? If they get a really nice South Bend lathe that I really like, I might hook up the trailer. The one I've pictured above seems to be pretty nice, but like I say, it's just a tad bit large. And no taper attachment which I would like to have. In fact, this lathe doesn't even have a smaller 3-jaw chuck. But I suppose I could remedy that easily enough.
The mag chuck is sold by the way. I should have grabbed it instead of just dreaming about it. Especially after having watched those mag-chuck rebuilding videos. The rebuild actually looks like a piece of cake. Now where am I going to find another Taft-Pierce mag chuck for $69?
I'm sure whoever bought it is going to have to rebuild it. I doubt that it would be of much use as-is.
I'm sure whoever bought it is going to have to rebuild it. I doubt that it would be of much use as-is.