Remove stubborn dowel pins on an XLO 602

Hey there, I am attempting to remove the knee on an old XLO (early version) 602 mill. I need to get the crossfeed table off and therefore its leadscrew out. There are two locator dowel pins under the dial for the crossfeed that hold the bearing housing for the leadscrew (which must be removed) on the knee casting. There is no hint of oil (or rust for that matter) on these pins but they will not budge. I tried hitting them with a cylindrical punch close to the diameter of the pins marked with a dash to see if any progress was made with a crackhammer... Nada. I don't want to go nuts on them incase I am missing something here and risk slightly mushromming them. Any advice would be much appreciated. Thanks!


-Kyle

Kyle,

I don't know that machine and am not totally clear on your predicament but just keep in mind that taper pins are often used for aligning components and the will not knock out..they must be pulled back out in the same direction they were inserted from.

Again, not understanding 100%, I would attempt to pull the component off that has the dowel pin going through it. Working a very thin screwdriver or some such thing under the piece and wiggling it back off, along with the pins.

Stuart

As Stuart have mentioned above, those could be taper pins. Almost all taper pins are soft so it easy to check. Best, in any case, is pulling the pins rather than punching. On one occasion for taper pins (Emco lathe) I had to drill and tap the pins and then those came out easily using a sliding hammer. For hardened pins it is more difficult, but the pin can be softened by heat applied to the pin top. I've used a very small oxygen-acetylene and/or plasma needle torch to temper and then to drill and tap (applying the heat until the head of the pin turns light blue and then gray), though sometimes just the heat can loosen the pin.

an Er collet chuck and a old draw bar , along with any thing heavy with a hole , make a useful pin puller .

Thanks for the info guys, I called up John McCartney (owner of the remaining excello stock and drawings) and he said he thinks they were dowel pins. I am wondering if a wheel puller would work. I am not sure the holes on the bearing housing that hold the bolts holding the housing to the casting are threaded at all. It would make sense to me that just the end part in the actual casting is threaded, which obviously doesn't help me. I went around with a sharp knife and could not find a slight groove to start working from unfortunately.

The job you're trying to do has been done many times before by multiples of god only knows and is not rocket science by any means. Really not going to get any valuable information here with out some pictures of the progress so far. We don't know if you have the crank handle and dial off or if you're trying to do the job *ss back words and going to destroy everything in the path to disassembly.
In regard to the pins, if dowel they are case hardened and drilling/tapping is not that difficult with proper technique! It could very well be that the bearing retainer will come off with the pins in place but we'll never know until we see what you've done to get where you're at. If you're trying to drive them in they might be in blind holes as far as I can tell, hit them hard enough with a big enough hammer and something will give but you may not like the results!
Dan

I have this problem all the time working on engine blocks. Here is my fix. I place a nut over the dowel with an ID the size of the OD of the dowel. Then I start welding on top of the dowel until I fill up the nut. Then I weld a coupling nut to the nut. Then I screw a slide hammer (mine is a 3/8" UNC for pulling the front pump out of a Chrysler 727 automatic transmission) into the coupling nut and pull it out. It has never failed.

Old three jaw chuck on a slide hammer, nuff said!
Mark

If it is a similar Bearing Housing to my Bridgeport, remove the housing fixing screws then wind the handle clockwise. This will push the housing off the knee from the inside. Works for my BP.

Charles

Every engine shop has to have a dowel puller kit.



jack vines

PackardV8 said:

Every engine shop has to have a dowel puller kit.

jack vines

Click to expand...

Posh, I like it
Mark

I've had a set like that since 1977. It almost never failed back then. It was probably the first time the engine was torn down and the dowel pins were virgin. Nowadays the blocks are 50 years old, they have been worked on by a "vice-grip" mechanic, and if the dowel pins are chewed up badly a collet most likely won't hold.

Sorry I have been away the last few days. I've been busy with other things. It is no longer critical that these pins come out as I have resigned myself to getting a different mill, probably the ubiquitous bridgeport which I can load and move myself in one piece (disassembly of the xlo was for loading and unloading). Unfortunately I can't access the mill to get anymore pictures than the one I took to see if the pins could be smacked out potentially, but I'll attach it just in case anyone is curious. I like cfrank's idea of threading the nut for the table over to push the housing off. That was the way I planned on doing it initially but it would not budge for me.

The 3 jaw with a slide hammer would definitely be worth a shot if I had acess to those tools, unfortunately I did not. I was trying to do the operation in the least destructive way as possible since me buying the mill hinged on my ability to break it down for transport and I didnt want to end up in a situation where I left the mill in a different condition than I found it, unable to move it with an angry owner.

Here is inside the knee showing the two holes for the locator pins.

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