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Harig Grind All #1 out of tolerance

kenpo11

Plastic
Joined
Feb 8, 2023
Hello everyone, First time posting and I thought I would start a question and answer session on a new project I'm working on. Hopefully this info can be used to resolve these Grind All issues. I just acquired a Harig Grind All #1. Upon inspection, I checked the runout and manually pressing on the V-block, I could get a movement of .005+..Not good. Also the fine adjustment screw for the V-block was missing and 3 teeth on the V-block for adjusting were broken. I have dissasembled, cleaned and inspected all the componets. Slight wear line on the center of the races from ball bearings. No physical or indicatable wear on the races..only slight visable bearing track line. I will attach a few pics of the project. Objective is to tighten this back to "reasonable" tolerances. Factory specs I hear is to within .0001 I will not be worrying about achieving that. Being I'm shooting in the dark here, I am looking for an option on tightening it up. My first notion is to grind the Back side of the bearing plate. The main housing has the races for the 32 bearings ground into the center of the body. No way to revive them. The front part which consists of the V-block is a 2 piece design. It is bolted from the back with (3) 10-32 screws which Sandwich it together on the bearings as the internal race. My thinking is if I grind the "back" half an undetermined amount, that will compress the bearings together to remove slop in them. Question is...How much? I was kicking idea around of starting with .0005, reasembling, testing it and working upwards from there. I can grind the rear portion easily but....it's going to be a feel it process. I would appreciate any suggestions. I have heard some people describe the races in these consisting of 2 halves ground and placed together to form a 90° for the bearing races and that is what decides the preload. The 2 halves are "Tightened" together. I will Attach pics..
 

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Grinding the flat face of the back half will probably reduce your free play. But with that kind of wear you may have some deviations from roundness even so once you get the free play down to a reasonable level. I think your approach is reasonable. Taking a little at a time is a good idea since you don't know if there will be tight spots once the clearance is brought down. It would have been good to check fore and aft movement before you disassembled it, that would have given you a better idea of how much needs to come off that face.

I might also investigate those bearing balls, first thing. You might find that they're worn and you can simply replace them to take out much of the free play. Measure them and see what you've got.

I've got a Grind-All #1 too, but the bearings are in excellent shape still. Hopefully will stay that way.
 
I just got a Harig No.1 off eBay. I had to make the T-nut and spacer bushing for the Allen head screw (I think that was used).
Mine has runout of +/-2 tenths when I push/pull on the spindle crank. When I have a .5" gauge pin mounted in the Vblock (with a load spreading block to distribute the point force allen screw pressure), and zeroed runout for the adjust axis of the Vblock, I still see +2/-5 tenths runout of the pin. I assume the V is the problem.
Thanks for posting these photos, I was wondering how it was designed.
 
Fortunately, the grind go-direction pressure can aid a Grind-All or a Whorley, I have bumped a nylon pusher block to a side for light pressure to reduce any slack radially or axially in spin devices.. yes this does not take away wear but just takes radial or end play.

New balls as Eric mentioned, likely the wear is in in the races as the ball likely to be harder. Grinding would need to be very accurate...may be able to trig the take to take up the amount of unwanted travel.

QT: (pressing on the V-block, I could get a movement of .005+..Not good.) Agree.

That would be a good sideline rebuilding Grind Alls back to new specs.
 
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Since it's apart already, I would grind .0005 off one bearing plate. Then reassemble the unit. Now measure movement. You aren't trying to measure the yaw of the spindle, but the axial movement. Depending on the amount of effort you want to invest, I would grind about 3/4 of the axial movement from the bearing plate. Then reassemble and retest. Rinse and repeat until either satisfied or tired of the task.

Ball tek will have new balls graded to size .0001 and whatever quality you want to pay for.

Anyone know if all balls are the same size, or if every other ball is a spacer?
 
Have you called Harig? It's been a while, but I once called Harig and talked to a very knowledgable guy who talked to me about what to do with a Grind-all like yours that I was considering buying.

At the time, they rebuilt their own units, too.
 
I have a very old #1 that I got from a member here. It was "crunchy" so I called Harig. They do in fact still rebuild them but it is not cheap (that is what the lady said, I did not ask 😃). I bought a new set of balls from them and the felt seals which were very reasonably priced.
 
Have you called Harig? It's been a while, but I once called Harig and talked to a very knowledgable guy who talked to me about what to do with a Grind-all like yours that I was considering buying.

At the time, they rebuilt their own units, too.
His name is Bob, he has been an Engineer with Harig for like 50 years.

He is a pleasure to talk with.
 








 
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