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Problem downfeeding on our surface grinder?

The problem is several times lately I have found that the wheel wasn't cutting anymore when I downfed. The first two times I just redressed the wheel and took about .005 off. I was almost down to depth and only needed a thousand to findish and retouched the work and finished the job with no more problems. Today I tried going down another .001 and didn't cut. I tried another .001 and nothing. Its a Boyar Schultz that we got on Ebay) The only time I ever found a situation like this was on an old hobbing machine and I figued it had a flat spot on the lead screw then. I wondered if there was an alternative explanation for this. How would I check this. Getting it fixed is not an option as this company has no money(except for the bosses toys) Ken

Reply to
clannorm
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Slip stick. I would say it's either a lack of lubrification or the ways are worn out and missing the scraping patterns (if there were).

You already did. :-)

A workaround would be moving up (a bit) and then back down.

Nick (who would be happy if he would have a surface grinder. Even with that defect)

Reply to
Nick Müller

Put a 0.0001" plunger type dial indicator on the head and measure the travel directly as a test.

Sounds like there is some wear on the downfeed screw and/or nut. You might be able to get around that by lowering the head by 0.010" or so and then backing up to 0.001" below the reading for the previous pass. IOW, take out the backlash.

Mike

Reply to
Mike Henry

the weight of the head should keep the head resting on the feed nut but if the gibbs are dirty, no oil or too tight the head is not moving freely in the ways.

John

Reply to
John

the weight of the head should keep the head resting on the feed nut but

if the gibbs are dirty, no oil or too tight the head is not moving freely in the ways

I cleaned everything when we got this and its getting oil. Gibs aren't too tight either. I'm mostly worried that I'm going to try downfeeding with no reslts till it all drops all at once and something bad happens. I am going to put an idicator on the thing and down feed and see what I find out over several inches. Ken

Reply to
clannorm

One work-around [not a "fix"] you might try is to clean and

*lightly* relube the downways with slick-50 teflon grease.

If this seems to help, you may want to check out using teflon or teflon composite tapes on the gibbs.

Uncle George

Reply to
F. George McDuffee

"A workaround would be moving up (a bit) and then back down." I took an indicator and ran the thing up and down. I found that I could turn the handle to feed down and there was no movement in a few locations. I then when up and came back down. The same thing occured a couple of times and then it worked ok. I will check the lubrication and ways. I was concerned I would down feed with no movement and then it would just drop causing too much excitement. Ken

Reply to
clannorm

I also would not like to have that on a surface grinder. To much noise ;-)

Nick

Reply to
Nick Müller

Worn nut or screw obviously. What kind is it? I may have some used Stuff

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Reply to
Gunner Asch

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