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View Full Version : Adjustable rotary tables (play in the worm gear)



Elninio
03-15-2011, 11:26 PM
http://i55.tinypic.com/2ldy5xh.jpg
Are rotary tables typically made like this? This is from a vertical slotter. More pictures here: http://sites.google.com/site/dannympwillems/misal-gardone2

Rich Carlstedt
03-16-2011, 12:39 AM
NO, Most Rotary Tables pivot the worm in and out for backlash control, or have the worm in an eccentric bushing, that is rotated in/out for adjustment.
Its possible that as the bull gear wears, or the worm, that even when buried into the gear, that backlash will occur. This is rare, unless the table is really worn.
The setup you have shown here eliminates that and will provide longer usable life, howevr it does that at the cost of thrust pressure, meaning it cannot take high dynamic loads, as only half a tooth ~ is being used in each direction.
There are no free lunches..
Rich

nice $$ table however

Black_Moons
03-16-2011, 07:19 AM
Nifty method of backlash compensation, Never seen that before. I hope your worm is a lot softer then that gear however.

(Worm ware = same reguardless of table position, Table gear ware = varys)

I would wonder a little bit about the 'ledge' beween the two gears maybe biting into the worm... Maybe give it a little deburring to round it over.

J Tiers
03-16-2011, 08:52 AM
Never mind the gears..... have a good look through the linked site.....

No scraping, at least as far as I have looked through it, but lots of pull-apart, clean, replace parts, and repaint work. Lots of machine pics too, innards especially.

TGTool
03-16-2011, 11:48 AM
VERY interesting machine in the link and very nice restoration job. A really handsome piece.

And then some interesting machines in the background. Are those small vertical spindle grinders?

Ryobiguy
03-16-2011, 02:06 PM
So it's a split worm gear huh? Never seen that before!
At first it looked like it was a ledge that was cut into it, but after looking some more (particularly at the teeth on the right side,) it is apparent it's a split in the middle and only one of the halves of the worm gear rotates in order to take up the backlash.

-Matt

Jaakko Fagerlund
03-16-2011, 03:14 PM
Quite usual to see that arrangement in a worm gear. Usually have seen two or four springs that tension the halves by pulling them "back in line" and thus against the worm. Though this can't be used in every application.