ran the #12 table past the limit!!

ok, Im back at this!!
I managed to get the table off with Cals suggestions of removing the gib and the entire table slid right off no problem( took it off by sliding it to the left)
But the lead screw is still jammed.. so I ordered a few spanners from McMaster and I am posting these in the hope that the VanNorman Gods will take pity on me...photo-1.JPGphoto.JPG
It looks as if the brass spanner nut is deformed.. maybe from the crash.. -probably from the crash...
as I was saying before, the lead screw is completely static.. stuck .. so I am really at a loss here..

photo-1.JPG photo.JPG
 
Hi Eddy,

I'm away from my drawings right now. I think I know what to do, but let me check a couple of things and get back to you tomorrow.

You will need a hook spanner to loosen the back-lash adjustment nut and lock ring, shown in the last photo.

Cal
 
OK, I think I know what happened. I think when you ran the table to the end, the feed screw managed to tighten the backlash adjustment nut until the screw bound up in the two halves of the nut. This happened because the lock ring on the adjustable screw as not tight.

Here's a drawing that shows the table feed nut on a Van Norman No. 12:
VN12_12 table nut detail.jpg

The fixed part of the nut is 12-619; it's a long cylinder with an internal ACME thread in one end, the other end has an internal thread for the adjustable nut, 12-620. 12-620 has an internal ACME thread and an external thread, which threads into 12-619. As the feed nut wears, 12-620 can be run in or out the remove the backlash in the table feed. 12-563 is a lock ring that is tightened against the end of the table casting to keep 12-620 from moving. Whoever tried to adjust the backlash on your table last left the lock ring unscrewed, so that 12-620 could move.

You'll need to rotate 12-620 to loosen it. I don't know which way you'll need to rotate it; it could be jammed in either direction. Based on your photos, I think it needs to screw in (clockwise) to release the leadscrew, but that's just an educated guess. Pick a good spanner hole in the end of 12-620 and give it a try. You can leave 12-563 alone.

I'm glad that you have the right tool on the way; trying to do this with a punch or whatever is a good way to further damage it. Give the external threads on 12-620 several shots of a good penetrant (not WD-40) and let it sit overnight before you try.

Cal

VN12_12 table nut detail.jpg
 
Cal,GOT IT!!!!
lots of beating and in the end I had to use a pipe wrench on the end of the lead screw to get it off the 620 backlash screw.. but it worked!!
thank you for walking me through all of it..
NOW.. 620 is pretty beat up, spanner holes are toast, the end is mush.. its pretty much garbage... are there any out there that people are selling?
Again thanks..
Eddy
 
eddysykes said:
Cal,GOT IT!!!!
lots of beating and in the end I had to use a pipe wrench on the end of the lead screw to get it off the 620 backlash screw.. but it worked!!
thank you for walking me through all of it..
NOW.. 620 is pretty beat up, spanner holes are toast, the end is mush.. its pretty much garbage... are there any out there that people are selling?
Again thanks..
Eddy
Click to expand...
Repair Parts Inc. can probably sell you one, but it won't be cheap. Several year back, Nelson had a parts machine, but I don't know if he salvaged 12-620 before he scrapped it; PM him and ask.

I think I would just turn the damaged part off and silver-solder on a new spanner ring, basically just a thick ring with the spanner holes.

Cal
 
Don't be so quick to scrap it! Do you have a lathe or know someone who has one? You can fix the end by truing it up and making a bushing/adapter. You don't use the anti-backlash screw too often, so if you can also true up the circumference on said lathe, you should be in good shape....at least enough to have a useful hobby machine.
 
thats a good idea.. rebore the spanner holes, silver solder up some meat on the deformed sections... Good as new
Thanks.. Ill do just that..
I have a clausing so its I can turn it .. right after I fix the veri drive!! Hmmmm, old machines... Sometimes I wonder..
 
Just joined this morning. I have exactly the same situation on my VN12. First day,showing the new toy off etc. Anyway it looks like you got through it. Any shortcuts? Or do I just need to get table off and go to it?

Les
 
Les Shelley said:
Just joined this morning. I have exactly the same situation on my VN12. First day,showing the new toy off etc. Anyway it looks like you got through it. Any shortcuts? Or do I just need to get table off and go to it?

Les
Click to expand...
Hi Les,

Welcome aboard! Sorry to hear that you're off to a rough start.

You don't necessarily need to remove the table. Try taking the gib out first (see post #15) and see if that loosens things up. Eddy's problems were complicated by the fact that the lock-ring on his backlash adjustment nut was left loose and allowed the nut to bind the leadscrew up; hopefully you won't have the same problem. Let me know if that works.

Cal
 
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