820 Compound Stuck in Crossslide

[Shiseiji]

Hello all. Not one of my better days. S/N 61328 built 1952 fitted with the later type compound with the "spud" for lack of knowledge of a proper term. So I made a ball turning tool with a "spud" and had it in out of the cross slide many times fitting it, checking tool height, etc. No trouble removing it until after the first real test and now it won't. Best I can tell the locking plugs are jammed though I can lift the tool from flusb by ~ 1/16". I've tried a chip of a thin Neodymium from a hard rive, cleaning, turning it with hemostats. All no-go.


I figure worse case I can drill and tap the plugs "if" they don't just spin in the hole. Big if.

So ideas?

As always, TIA!

Ron

 

[Ulma Doctor]

most likely, the pin has been mushroomed.

you may be able to use that to your advantage by using a left hand drill bit, just under the threaded bore size.
run the drill in reverse, the pin may come out- or at least get the pin to move

if you can put a hole in the pin, a bolt extractor bay be employed for added effect

 

[John TV]

If it starts spinning from the above procedure, could you use a dremel tool with thin shank to grind a screw driver slot?


Sent from my iPhone using Tapatalk

 

[ericc]

On my South Bend, the plugs are wedge shaped, so they will not spin if they are drilled. In the back of my mind, I wondered what would happen if they got stuck. If a magnet is not strong enough, maybe JB Weld or some strong glue would help. There is a similar pin which is totally unnecessary on the Shop Fox compound slide, and it is a huge drag when it gets stuck. I ended up getting it out by tapping on it for about 20 minutes. I had a TIG welder standing by, but the tapping was preferable. BTW, that Shop Fox lathe really has some quality and design issues. Things don't fit correctly and it is really easy to get things so jammed up that it takes forever to get them loose. We still are having trouble with the stupid change gears. I think that there was a little chip combined with a crash by the previous owner.

 

[Shiseiji]

Thanks all! The wedge is a possibility. I try to avoid cross-posting, but if I ask on the Logan forum maybe Scott Logan will know. Since this forum is so much larger I wanted to start here. The left hand drill and a slot are both viable I believe.

Rob

 

[Shiseiji]

If a magnet is not strong enough, maybe JB Weld or some strong glue would help.

Sadly, outside of white or yellow glue. I am cursed regarding any shop adhesive. I purchased what was proported to be high quality, thick, dried in 10 - 20 seconds cyanoacrylate. Tried to glue the magnet chip to a dowel. Cleaned it with acetone. Two minutes later I was still waiting for it to dry. Wiped off 90% and put accelerant on the dowel and it still took another 30 seconds.

 

[ericc]

JB Weld is kind of reliable, at least much better than cyanoacrylate. The cheap stuff is especially unreliable. I had the hardest time getting it to stick a chimney back on a model building. Then the nozzle clogged, and my fingers got stuck together. One and done for the tube. JB Weld is advertised to hold something like 4000 psi. That will be about 160 lbs for that screw, which could easily be derated by a factor of 3 due to possible flakiness. So about 50 lbs. If that doesn't do it, you'll have to do something more invasive. I basically have little regard for much of the engineering that goes into this stuff, and I would be tempted to just drill the whole thing out. When you replace it, make sure to chamfer and harden the pin so this is un(less) likely to happen again.

 

[wa5cab]

The problem with using any (good or bad) adhesive to aid in removing the locking pins is that unless you remove the compound slide from the carriage and fixture it so that the stuck locking pin is vertical with the pin that you are attempting to glue a puller rod to pointed downward. you can pretty much bet on the pin and puller rod also being glued to the cross slide.

A magnet is unlikely to work because the cross slide with the beveled locking pins stuck in it is also ferromagnetic.

As my understanding is that you did not make the replacement LA-744's out of hardened material, they are not worth salvaging. So the simple and straightforward solution is to dismount the LA-49-4 compound rest base, mount it on your drill press or mill and drill and tap the pins for a puller (piece of all-thread. With nuts & washers as required. After that, the simplest final solution is to order the two pins from Logan.

And the proper generic name for the truncated right-circular cone on the bottom of the base is I think "Pintle".

 

[Shiseiji]

Resolved. Thanks for all the suggestions. The first thing I had done was remove the cross slide. Supporting it on some 2X I was able to use a long thin punch to tap on the "inverted cone" pintle. That pushed the lock pins back inside the cross slide. Scott Logan passed on that the lock pins are wedge shaped and gave the inverted cone description. I cleaned the holes then used Kroil on the lock pins. Tapping on the pintle/inverted cone pushed out the lock pins and the shop made pintle slid right out. As Scott suggested, the 66 year old lock pin ends were badly burred with deep impressions from the lock screws. I also suspect they are quite worn as after I removed the burrs, the screw heads are almost seated in the crossslide. Now to figure out if the shop made pintle can be made to work or written off as a lesson in the school of hard knocks.

 

[Shiseiji]

As my understanding is that you did not make the replacement LA-744's out of hardened material, they are not worth salvaging.

My apologies for the misunderstanding. I didn't make replacement LA-744. I turned a pintle and press fitted it in the base of the ball turner. I do wish I"d expanded the parts illustration more. It clearly shows the locking plugs have a wedge shaped end.