The Home Machinist!

I'm finishing up a restoration of a Delta/Rockwell Unisaw. The cast iron top is a little worse for the wear. I've tried all the usual tricks to clean it up but it's just not looking very good. I was thinking if there was a way to take a couple thou evenly off the top that might make a difference.

I have no idea what they are or are capable of, but is this something a surface grinder could do?

Or this something that would require a much bigger machine?

The first question is how big is the table ? Most common SG have a work envelope on 6X12 or 6X18.

Those are small SGs

The answer is yes. Which is how it was probably manufactured in the first place

Watch the first video from about the 7 minute mark and the beginning of the second one to see how it's done.

https://www.youtube.com/watch?v=u5ctJm9eyOs
https://www.youtube.com/watch?v=K_cJ4IN6dCw

-- Russell Mac

Bill Shields wrote: ↑Fri May 14, 2021 10:31 pm Those are small SGs

The answer is yes. Which is how it was probably manufactured in the first place

Depends. Such surfaces are often finished on a Blanchard. If the grind marks are circular, most likely Blanchard (there's other circular types, however). If they're straight line, yeah, surface grinder is most likely. Could simply be done on a planer, too.

H

VelocityDuck wrote: ↑Fri May 14, 2021 8:14 pm I'm finishing up a restoration of a Delta/Rockwell Unisaw. The cast iron top is a little worse for the wear. I've tried all the usual tricks to clean it up but it's just not looking very good. I was thinking if there was a way to take a couple thou evenly off the top that might make a difference.

I have no idea what they are or are capable of, but is this something a surface grinder could do?

Or this something that would require a much bigger machine?

A surface grinder won't do the job. You need a blanchard grinder; the table saw top is about 23"x30". A surface grinder can't handle anything that large. As Harold mentioned, it could be done on a planer if you could find one.
I wouldn't bother trying to flatten the top. If there are shallow depressions on the top, that won't affect it's use as a saw for wood. Being cast iron, any irregularities were present when the saw was new.

Mr Ron wrote: ↑Sat May 15, 2021 4:01 am A surface grinder can't handle anything that large.

Not so. As Bill said, you just need a big surface grinder. The second video I referenced above shows a big SG finishing a table saw top. The first video shows a Blanchard grinder flattening the same top before they used the surface grinder to remove the circular marks left behind by the Blanchard.

I'm kind of assuming that this was a two-step process because it would have taken forever to do the initial flattening on the surface grinder. Can somebody confirm that guess?

-- Russell Mac

rmac wrote: ↑Sat May 15, 2021 12:08 am Watch the first video from about the 7 minute mark and the beginning of the second one to see how it's done.

https://www.youtube.com/watch?v=u5ctJm9eyOs
https://www.youtube.com/watch?v=K_cJ4IN6dCw

-- Russell Mac

Yep... That's exactly what I need. Sounds like I would need to find a place with a Blanchard grinder and a surface grinder. Which is probably impossible in Panama City, FL.

Table is probably flat enough already to bypass the Blanchard step

Mfg.com and search surface grinding florida.

Southern Grinding Services in Pompano Beach, FL does both.

I got a free Delta table saw a few years back that had several deep grooves in the table near the saw slot. We imagined it had been used to cut tiles. I found a fellow who dealt in used Delta saws and he had a nearly new table that swapped in with no problems. You might consider that as the new table was far cheaper than a regrind would be.
--earlgo

Grinding? If you want it really flat, I want to see it scraped!!

Are you grinding for appearance or for use? I've used epoxy to fill divots in drill press tables and vises and it works fine. Are you talking about a depression or pitting from rust?