VN Vn12 Table Feed Screw Backlash Adjustment Help

[gcaldicott]

HI all,

I have attempted to follow the instructions in the VN12 manual to adjust the table feed backlash. I have been unable to loosen the check nut "A" in the diagram below. Which way should I be attempting to turn it it to loosen it? Should I be pushing or pulling from the perspective of the diagram below. I assumed I was to push to have the nut move away from nut "B", but I have had no success (bending the 1/4" bars that I have been using). I also tried the other direction without any luck either.

Any help would be much appreciated.


Thanks,
Greg

 

[Cal Haines]

HI all,

I have attempted to follow the instructions in the VN12 manual to adjust the table feed backlash. I have been unable to loosen the check nut "A" in the diagram below. Which way should I be attempting to turn it it to loosen it? Should I be pushing or pulling from the perspective of the diagram below. I assumed I was to push to have the nut move away from nut "B", but I have had no success (bending the 1/4" bars that I have been using). I also tried the other direction without any luck either.

Any help would be much appreciated.
View attachment 141175

Thanks,
Greg

Hi Greg,

Part "B" is an externally threaded sleeve that threads into the nut assembly, which is in turn held into the knee casting by a set-screw. Here's what it looks like from above, with the table removed:

Part "A" is an internally threaded ring. It locks "B" by pressing against the left end of the casting. It's shown in the loosened position. IIRC, the threads are right hand, so you would need to turn "A" counter-clockwise (as viewed from the left) to back it away from the casting.

Since it's stuck, I would remove the table and use a pin-type side spanner wrench like one of these (type A)
https://www.mcmaster.com/#pin-spanner-wrenches/=15ffuet

It's a very good idea to pull the table on a newly acquired No. 12, just to inspect and clean things anyway.

 

[gcaldicott]

Thanks Cal. That is very helpful. I was definitely going in the wrong direction. I did have the table off and cleaned all the oil passages etc. This is my first mill and I just didn't think to check backlash before reassembling.
Greg

 

[gcaldicott]

Hi Greg,

Part "A" is an externally threaded sleeve that threads into the nut assembly, which is in turn held into the knee casting by a set-screw. Here's what it looks like from above, with the table removed:
View attachment 141194
Part "B" is an internally threaded ring. It locks "A" by pressing against the left end of the casting. It's shown in the loosened position. IIRC, the threads are right hand, so you would need to turn "B" counter-clockwise (as viewed from the left) to back it away from the casting.

Since it's stuck, I would remove the table and use a pin-type side spanner wrench like one of these (type A)
https://www.mcmaster.com/#pin-spanner-wrenches/=15ffuet

It's a very good idea to pull the table on a newly acquired No. 12, just to inspect and clean things anyway.

Cal I just re-read your post. Did you accidentally transpose your references to A and B. According to the diagram, A is the big nut that locks B in place. It instructs me to loosen A in order to Adjust B. I think you said it the other way around.

Please clarify.

Thanks,
Greg

 

[Cal Haines]

Cal I just re-read your post. Did you accidentally transpose your references to A and B. According to the diagram, A is the big nut that locks B in place. It instructs me to loosen A in order to Adjust B. I think you said it the other way around.

Please clarify.

Thanks,
Greg

You're right, sorry about that. I corrected my original post.

 

[gcaldicott]

Cal,

The spanner wrench loosened the locking nut easily. I adjusted collar B to reduce the backlash to 10 thousands. It was at 25 thousands previously. When I reduced it further, there was excessive drag when moving the table to the left. I did the same with the cross feed. Any less than 10 thousands and it was a little tight at the two extremes of saddle movement.

Thanks,
Greg