Can you replace roller guides with linear rails on a surface grinder?

[learning80]

As per subject, I am looking at purchasing a surface grinder with roller guides that are worn. I am wondering if there are any reasons if you can't restore or fix the rolling guides that you can't replace them with Hiwin linear rails (or some other linear rail brand). The process I would use would be to install ground iron or steel where the rails were, after removing them. Then scrape the ground iron or steel flat and parallel with one another, and bolt linear rails / trucks to this area. Obviously one side would take the rails and another the trucks. You would probably have to replace a few brackets for hydraulic cylinders etc. if you did this but that doesn't seem too difficult to me, and look at sealing the area a little better from grinder dust. Thanks for any advice.

 

[Milland]

Standard rail will have its own errors you need to compensate for. You don't just need to scrape the rail mount surfaces, to do a good job you have to mount the rails to a "rough scraped" surface, map out errors of height and axial twist along each rail, then rescrape and check to see if you're at least .0002" uniform along the length of travel.

Then you need to get one rail straight lengthwise, then match the second rail to it. This presupposes you got both to the same plane during the initial height fitting, or accommodate any height errors in the block mounting (not recommended).

Then there's stiffness - use a bigger rail than you originally think is going to be acceptable. The span between mounting holes allows for more flexibility than I like, I prefer rails with close hole pitches (seen on better linear way machine tools).

So, not a simple job to do right. Good luck!

 

[JPD]

Why not just have the roller ways re-ground? What machine is it?

 

[Richard King]

I would think it would be cheaper to buy a used good grinder and use as-is.. You would have to mill pockets to mount the rails to or coolant could run in there on an existing iron on iron. On another thread a week or so ago I linked a website where a guy makes roller ways for grinders. I don't have time now to find it. It is in the Abrasive section if it's not here. I've mounted Linear ways on VMC and we had to scrape the mounts for accuracy plus they are bowed like a banana when new and as Midland said need to be aligned. Chevilar comes from the factory with roller ways as does Brown & Sharper the micro masters. On the table ways..

 

[CarbideBob]

Ball way or roller now? Side to side only or in/out also?
For me the in/out has to be just right as the 4th and 5th axis above care about it a lot.
This is a big project and may involve serious remaching of the base for fit.
Also Hwin ways do not have real great flatness run specs so you might not be happy with the resulting surface finish for flat grinding.
At the min I would suggest using 3 or 4 trucks per rail to help average out the errors.
Yes I have done it but not for a flat grind machine as that a engineering nightmare. Hwin sells many types from balls to rollers and many classes of accuracy.
Here is what sucks. The price tag goes way, way up for the good stuff.

Ball ways can be fixed by a long section of drill rod, lapping compound and new balls. Yes this a hack but it works if careful. (not that I would ever do that ..)
Needle or true rollers not so easy.

Seems like a good idea and I'm all in for the try.
Maybe works and maybe not but if you are like me you have to swing the bat hard and see what happens.
Bob

 

[michiganbuck]

Some machines like the Cincinnati Tc grinders are made to be able to replace the ball ways, and the ball ways can be ground and shimmed back to their original height.
Redesigning a ball or roller machine into a scraped oil way machine would be a big project, and likely to fail...but anything is possible...grind to .001 bolt them in and then scrape.. seems possible.
Qt Richard (I would think it would be cheaper to buy a used good grinder and use as-is.
Or buy an ok oil way machine and scrape it back to good.