Thread: FP4NC shift drum pins broken

These are the pins that the shift motors drive to turn the shift drums in the main transmission. In the first photo you can see 2 pins broken off flush. The second photo shows another drum where they have been replaced previous to my ownership with solid pins, so obviously this is not an isolated occurrence. The white bushings are all broken also in the first drum. How would you go about removing the remains of the split pins? I tried hydraulicing them out with grease and a .069" gage pin but the grease squirts out of the split. The holes are blind. Removing the drums looks like way too much complication, looks like the whole 23 gear trans has to come apart for that.

Has anyone else here been through this?

I was going to suggest just tapping the split pins, but then realized that .069" would mean a #2 tap . That's a pretty petite tap to try to run in an awkward space.

Regards.

Mike

Good suggestion, but aren't those pins too hard to tap?

I have the Y axis off the machine so I can work vertically on this without trouble, but there's no using a mill on it. And the drum turns freely in it's bearings.

I once made a tool to remove needle bearings from blind holes but you'd need at least 1/8 inch clearance between the end of the pin and the bottom of the hole and even then it would be seriously tricky with such a small hole in each pin to feed it thru. If those pins are bottomed out in their holes that will be one seriously tough nut to crack. Then we get into desperation moves like a Dremel with the plastic drill press attachment epoxied to the shaft and attempting to grind each one out.

Take your .069 gage pin and glue into the roll pin clamp on with vice grips and pull or tap out with a hammer.

Spray some PB blaster in the pins and get a quality EZ out.The twisting will break loose some of the resistance.Then use some vise grips on the ez out to drive and pull simultaneously.As I'm sure you know to be careful with the ez out or you'll have to get half it out too.Pending on if these broke from fatigue or if a gear crash.I would use solid pins for the former and split pins for the latter.

I've used this technique succesfully in togher looking situations.

Where can I get an EZ out that size?

MSC etc. ? Screw, Bolt, Stud & Pipe Extractors - Screw, Bolt, Stud & Pipe Extractors & Nut Splitters | MSCDirect.com

Don't forget they size them for the screw size to remove not the hole size.I would get an assortment and use the biggest possible. You also might want to hand drill them out a little bigger to lessen the wall tension.

Originally Posted by SIP6A

Take your .069 gage pin and glue into the roll pin clamp on with vice grips and pull or tap out with a hammer.

I wonder if the glue wouldn't hold perhaps there exists some specialized "rust weld" acid gel for such things ?

Don't see why a solid carbide end mill would not cut those pins out.....
Set the slide on the table ...you do have another Deckel,yes... come at it using the horizontal spindle......
Fab a small dog clamp using one ot the tapped holes on the casting and a strap that overhangs the drum and a screw tapped into the strap...tighten the screw against the face of the drum
to prevent rotation.....
Mill close to size. fish out the remaining tinfoil.....
Cheers Ross

Originally Posted by Milacron

I wonder if the glue wouldn't hold perhaps there exists some specialized "rust weld" acid gel for such things ?

I have used a product called "Loctite super glue control gel" I have also used a product called "crazy glue gel" both of these products work when you have a space of more than a few thousands of an inch. I have bought both of these at the hardware store or craft store.

The problem with using an ez-out is that when you twist the ez-out in to get a grip you are expanding the roll pin and making it grip tighter. What useally happens is that you twist off the end of the ez-out off in the end of the roll pin. Now you have a roll pin with a hardend taperd pin locking it in place.

My guess is that glue would not work....Roll pins are formed from sheet stock and spherodized making the internal surface pretty smooth and slick
would think glue unless you were able to get a small diamond tool or stone inside and roughen up the surface would not adhere with enough grip to pull that pin out....
But again might work.....

Might try small hardened self tapping screw...grasp the screw with vise grips and coax out with a slide hammer...(I have a pair of vise grips with a nut welded on the fixed handle that fits my
slide hammer thread).
Cheers Ross

My bet's on the screw extractor.They are just split roll pins. Hell there is not even the least bit of oxidation on this stuff, unless you include the black oxide. If you get them to spin they'll go.

If you go this way Do Not forget the penetrating lubricant to get between the pin and bore, and I mean good stuff not WD 40.

Originally Posted by AlfaGTA

Don't see why a solid carbide end mill would not cut those pins out.....

In my experience with carbide end mills, the interrupted cut you would encounter with the split in the pin would break the end mill cutting edge immediately. Re glue, I agree that's why I'm suggesting to rust weld it to a rod with acid.

Re screw extractor...maybe, but seems like 1. It would tend to expand the pin and make it even tighter and 2. It might not grip in the first place due to pin hardness.

I think the screw extractor will put way too much force against the leading edge of the split. Probably more force pushing it open than what will be directed to rotating the pin.

What about trying to clean out the pin bore as much as possible, and use a pin that will fit into a slide hammer.
Find whatever loctite product will give the best grip and see if you can get the .069 pin to hold well enough that a slide hammer will pull them out. Loctite primer will greatly speed up the process. You might have to do several tries to fully clean the oil out of the pin bore to hold.
Put some grooves on the pin so the loctite holds better, and if you can find a ball shaped burr that small use a dremel to grind a radial groove into the split pin.

Failing that, maybe you could use Loctite or even epoxy to fill up the pin gap well enough that it would allow you to hydraulic the pin out.
Do them one at a time maybe, with the split facing down as good as you can to allow the Loctite to fill the split through gravity.

Final try before dis-assembly would be to machine a pin with a key sticking out of it to fill the gap but it probably would be too difficult to get it to fit closely enough to get enough pressure from grease to drive it out.

Chris

Turns out those pins aren't all that hard, they are spec'd at 43Rc. The only extractor I could find that was that small was a spiral extractor and I refuse to even momentarily consider one of those miserable things for all the reasons listed by you guys above. I'm not confident enough that a straight extractor would work well enough to make one that size. So I briefly considered TIG welding a ball on the end of the pin to pull it with and promptly discarded the idea. The self tapper sounded good but the hole is so small. I looked for a sheetmetal screw small enough and couldn't find one, and the hardware store was closed. So I went back to my mechanic's roots and got medieval on it. I picked a few small drills out and used a cordless drill, started .010 larger than the hole and drilled through the pin. Not pretty sounding but it went. Went .010 larger and drilled it again. Another .010 and the pin relaxed enough to spin in the hole, and I picked it out with a scriber. By this time DD had confirmed that this is how he removes split pins, and says he catches the pins on the drill and spins them out. So the next one, on the 3rd drill I deliberately jammed the drill in the pin and used it to pull the pin out.

Piece of cake. Spent more time thinking about it and posting about it than doing it.

Exactly, too much talk not enough rock. FWIW I would not have suggested you do something that I myself had not done many times successfully.
Your only supposed to twist ez outs right below their yield point and then back off, not beyond and then blame the tool.I guess some people can feel it and others can't.I would have done this first, and if no action I would have reached for my Milwaukee Magnum and some Clevelend 135 split point cobalt jobbers.

Like the others I had hypothetical ideas that might work: some chewing gum on a stick, an ultra powerful magnet, C-4 , or swaying a magic wand over it,to the solid fo sho would work idea of scrapping the whole Y casting and making a new one. Didn't think you were looking for that though.

On a side note, sorry Mud.I'm really glad I didn't buy this machine as it seams to have been worked hard and put away wet.

You didn't buy it because it wasn't below $.06/lb.

The hydraulic methode might have worked if you used clay and/or Tig welded a bobble on the end of the pin and file that to fit the split
But I know it is a afterthought (Mustard after the meal we say)

Peter from Holland