Table speed

I have a small manual surface grinder.

the table is moved via the handwheel by a rack and pinion setup. I find it is hard work to move the table across and back very fast. Should i be goign fast or slow? I find that faster table feed with fine cuts give the best finish.

It's an acquired skill, kind of like rubbing your tummy and patting your head at the same time. It comes with practice. After first carefully touching off on the work, start cycling the table back and forth with the wheel totally behind the work. When you get into a rhythm that carries the work completely past the wheel at each end of the travel, start advancing the cross feed by the same increment each time. Do this by feel; decide how big of increments you want to feed in, and translate that to something you can do by feel, such as 1/2 turn at a time, or 1/4 turn, or so much twist of the wrist. Then, just keep doing the same thing all the way across the work. Watch the sparks, not the hand wheels; if the sparks turn dull orange, it means heat is expanding the work and forcing the cut deeper, or the wheel has glazed. In which case, stop at the end of a table stroke with the wheel off the work, and figure out what you need to change.

[FONT=&quot]Bennis[/FONT]

I’m sorry, I see I didn’t really address you question about how hard the table should move. A grinder with ball ways glides so easy that one spin of the hand wheel and it will coast all the way to the end of it’s travel (not recommended when actually grinding.) You mention a small manual grinder with a rack driven table; this sounds like an old Boyer Schultz; they had rack driven tables, and flat ways. These tables are always more work to keep moving, but work OK once a film of oil covers the entire surface of the way. When starting, give the lube pump a pump, and run the table back and forth a dozen or so times. If it is still stiff, you likely have plugged oil lines. Pull the table and see what is going on.

I also should have noted that most manual grinders have a locking knob on the table feed hand wheel. Loosen it, and you can reposition the handle so it’s in the most comfortable position to keep the table stroke you need going.

Good luck.

[FONT=&quot]Dennis[/FONT]

Dennis, Its a Repco Power grinder, made in Australia. It has one flat and one vee way, no rollers

no hand pump either. i am considering fitting a gear pump to constantly pump oil, but im not sure how much this will affect accuracy. With a low flow it should be ok (wont lift the table).

I should realy have it checked for straighness, and re frosted as it is worm smooth, but it is perfectly accurate for the small parts i do.

I don’t think you want a gear pump; I would think it would make the table float, and lose all accuracy. I recall reading where each pump of an automatic interval type lube pump would raise the table slightly, and be visible in the ground finish. I think what you want would be the same as the manual Bijur pumps used for “one shot” lube on milling machines. See: http://www.lubesite.com/pages/Lubeproducts/MCP-5.htm

These use “meter units” at all the outlet ports that meter just a drop of oil each time the pump is pumped. Takes a while to get the oil to flow when the system is new, but adds just a very small amount when in continuous use. Give it a pump between parts (or passes) when the table starts to feel stiff. Poke around their web site, it seems they claim to be international, so should have some distributors in Oz.

[FONT=&quot]Dennis[/FONT]

Oil that sits for a long time tends to turn to varnish between the ways. Older machine ways tend to wear into a closer fit. Pull the table, clean ways with lacquer thinner and skotchbrite.Ways may need to be rescraped to minimize area of contact.Handwheel bearings may need replacement.Get proper lube to table.
Grinders spend their lives in the worst enviroment in a machine shop.

I dont know if the question your asking is the traversing speed of the table if it is the table speed is approx 30 ft per minute, the finer the grit the finer the finish.
MBB

New Norton, Warner & Swazey, sales literature boasted 50 surface feet per minute as a table speed on their 6 X 18 and 8 X 24 S-3 type surface grinders.
John