Enco knee mill lead screw problem

[wframe13]

Fresno Ideaworks, a maker space that I am part of has an Enco knee mill. It has similar problems with both the cross feed and the table lead screws: when cranked counter-clockwise, the nut holding the cross feed crank and the left side crank on the table unwind a little resulting in 1 or 2 turns of "backlash". Obviously this is not correct. On the table lead screw, if we use the tighten the dial nut so that the dial is rubbing on the table, everything is fine for a few turns then the nut will unwind and the giant backlash returns. The same sort of thing is happening with the cross feed lead screw and crank.

Looking at the Enco mill manual/parts list, it lists a couple of "adjusting spacers" in the bearing assemblies for both lead screws. I am guessing that these spacers belong between the thrust bearing and the sleeve that the dials fits on. Then the crank is positioned at the end of the sleeve and the nut is attached. The order of the complete assembly would be bearing, adjusting spacer #1, adjusting spacer #2, sleeve, crank, and nut, with the dial just riding on the sleeve. Unfortunately, these spacer seem to be missing for our machine.

My questions:
1 - Is my guess at how the bearing assemblies are supposed to go together correct?
2 - If so, what might these "adjustment spacers" look like? Are they simply flat washer?
3 - If flat washers what dimensions?

Any and all comments and suggestions will be greatly appreciated.

Regards,
Bill F.

 

[matthewsx]

Have you looked at the Bridgeport parts diagrams on H&W’s site?

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There‘s a good chance parts got removed at some point, might be the same or similar to Bridgeport. Or H&W might have the Enco spec part.

John

 

[wframe13]

John, Thanks for the suggestion. I check H&W's parts list. Their drawing does not show the same spacers, but I will definitely give them a call tomorrow to see if they have any ideas.

Bill

 

[Jim F]

Use a dial indicator to measure movement.
The Bridgeport I use is worn out, I use a mag base and dial indicator to measure movements.

 

[wframe13]

Jim F, Our problem is not the measuring, we actually have a DRO for that. One of the problems is that on the table we have a power feed. The backlash is not in the lead screw nut, its in the connection between the lead screw and the table. With this slop in the table to lead screw, when it feeds left to right, the lead screw shifts to the right and the power feed gears move out of mesh. Once that happens the power feed can not feed from left to right.

On the cross-feed, the problem displays as the nut that holds the crank backing off when cranking counter clockwise. The nut is tightening down on the dial not on the thrust bearings. I'm pretty sure this is the case on both lead screws. So we need the "adjusting spacers" so the nut can tighten down on the bearing through the sleeve and spacers.

I hope that makes sense.