Shopsmith Forums

JPG wrote:I have tried using a box end wrench the size of the allen wrench. That also eliminates the twisting allen wrench. Granted they are short armed when that small size.

No one has mentioned 'gentle' tapping to apply the torque. Gentle at first with increasing lack of gentle. Then gradually increasing size of hammer. Main problem can be stripping the allen wrench(always use a new one for stubborn stuff) or the screw socket.

I cannot help but wonder how heating the inside object helps.

Expands, then contracts again when it cools, hopefully freeing things up in the process.

rpd wrote:

JPG wrote:I have tried using a box end wrench the size of the allen wrench. That also eliminates the twisting allen wrench. Granted they are short armed when that small size.

No one has mentioned 'gentle' tapping to apply the torque. Gentle at first with increasing lack of gentle. Then gradually increasing size of hammer. Main problem can be stripping the allen wrench(always use a new one for stubborn stuff) or the screw socket.

I cannot help but wonder how heating the inside object helps.

Expands, then contracts again when it cools, hopefully freeing things up in the process.

Why not dry ice first? Liquid nitrogen is more difficult to obtain.(unless thee is a dermatologist).

JPG wrote: I cannot help but wonder how heating the inside object helps.

I thought that too until my uncle showed me. I looked puzzled I'm sure when he broke it loose after I tried for days.

His explanation came with a series of questions such as what does thread sealer or thread locker do? Then what does corrosion do? So, if it microscopically fills the gaps between the two dissimilar metals increasing the coefficient of friction between and around the threads and we can't get a penetrating oil in, how can we change the coefficient of friction within the pitch of the threads?

Heating it to expand the dissimilar metals was his answer and heating the metal that expands the least as the source to evenly heat (thus expand) the metal that expands the most will appear to tighten it as surrounding metal expands.

What did we do then? We created movement along the pitch of the threads at a dissimilar rate. The more rapidly expanding metal is a heat sink and will pull the heat from the inside out fairly quickly and the surrounding material will not compress it as it would had the outside material been heated. That slight movement along the spiral axis of the
thread pitch from the inside out can change the coefficient of friction enough to get it free.

Does it work every case? No. You saw it work today, remember it. It can save you a few times. Every one of them counts he said.

I've never forgotten it, and I have done the same thing with Phillips screws and a sacrificial screwdriver tip.

It may work, and it may not, but it is a consideration.

Everett

So works for steel IN aluminum but not aluminum IN steel?

That's where I have used it successfully. I don't think Steel and Steel is a likely candidate either beyond general heating the area which we've all done

Steel in steel often breaks requires (best case) left hand drill bit to drill a centered hole then tapping an ease out gently to bite within the hole and back it out. Sometimes just the bite of the left hand drill will bring it out.

Japanese mtg often employ alloy screws in steel as they are malleable and distort to form fit the threads.


Everett

Kind of the same thing but different (the movement between the two different metals). When I was overhauling aircraft generators for the Air Force we used somewhat the same principle to remove main stator irons from the housing. The housing was almost always aluminum (C-5 housings were Magnesium). The iron was a shrink fit in the housing and sometimes further secured with screws or pins. The technique was based on the different expansion rate of the aluminum and steel when heated. We put the housing with the main stator iron installed in a 300 degree oven. Timing was critical. Too little time or too much time in the oven and nothing would move just like room temperature. When you hit the sweet spot the stator iron would almost fall out of the housing.

Does this heat treatment procedure work the same when the screws are tapped into cast aluminum?

I have a "manual" impact driver that is generally successful removing such parts using the correct allen bit. It's one of those you simply hit with a hammer and it turns that force into a turning force. I suggest Kroil, 24 hour wait, followed by a single blow with an impact driver. That almost always works for me.
I dont use power impact drivers because I find that those do often damage the bit or the socket screw.

tucsonguy wrote:I have a "manual" impact driver that is generally successful removing such parts using the correct allen bit. It's one of those you simply hit with a hammer and it turns that force into a turning force. I suggest Kroil, 24 hour wait, followed by a single blow with an impact driver. That almost always works for me.
I dont use power impact drivers because I find that those do often damage the bit or the socket screw.

You beat me to it. I was just looking for a picture of one when you posted. They work excellently and I have used one many times. They never fail, at least for me.

https://itstillruns.com/use-hand-impact ... 09810.html

Wow! I was blown away with all of the excellent tips to solve this problem. Thank you for all of the posts. This is what I did to solve the problem. I took the table out of the carriage and placed in upside down on a workbench and clamped it in place. I used Blaster penetrant (available at HD) on the hex bolts and let them set for about 30 minutes and then lightly tapped the bolt heads with the wooden handle on a putty knife. I sprayed on a second coat of Blaster and waited another 30 minutes then tapped again. I went to Harbor Freight and bought a long ball hex set and a 3/8", 17 inch breaker bar. I used the breaker bar and a 5/16" long ball hex wrench to loosen the bolts. Hooray! It took a little elbow grease but the Blaster and the torque from the breaker bar did the trick.

Tony Heinrichs
Retired Navy Seabee