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Fix for my Bridgeport knee adjustment

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Now that the Bridgeport is all back together again I need to fix the knee adjustment shaft and crank. As you recall I stated that there was a fix that needed to be done. Since I'm not restoring the machine to original condition I made my own crank and fixed the shaft to make it work.

First a couple of pics to show what is wrong with the knee adjustment mechanism. Apparently during a move in it's career the handle and shaft got bent. Here's what it looked like when I got the machine.

You'll notice that the clutch mechanism it partly broken, but still useable.

Here's a side view. It is noticeably bent.

In order to get the clutch off you need to use the collar behind the clutch to jack off the clutch. But I can't do that because the shaft is bent and would not allow the clutch part to come off. What to do? Well, I broke the rest of the clutch with a hammer. But there still was a small shoulder to get the nut over. At least I was able to get at the screws that hold the collar in that holds the shaft in. You can see the broken parts of the clutch on top of the ways.

I finally got the shaft out. Now what? Well I need to remove the gear and bearing so I can put the shaft in the lathe and turn off the rest of the clutch.

The shaft would not fit through the hole in the spindle of the lathe so I had to set up the steady rest. Here I've turned off as much of the rest of the clutch part as I could. That threaded part with the hole in it unscrews but I still need to get past that bent part, so I cut it off with the hack saw.

Here is what's left after trimming the clutch and cutting off part of the shaft.

Here's a pic of all the parts that go into the shaft of the knee adjustment screw, plus the broken handle.

Here's a close look at what the clutch part looks like on the handle. Somebody had welded the two parts together. While I was using it during the tear down to move the machine into the basement I broke the handle. So I welded it back together. Unfortunately I grabbed the handle to move the machine and broke it again. I decided not to fix it this time.

Here's what I did to fix it so I can use the knee adjustment. I decided I was going to make a part that would fit over the shaft like the clutch part and then have a hex on one end so I could use an ordinary socket wrench. The first part was to turn the round part and cut the flats for the hex. I used a piece of hex stock with a 1/2" hole and two set screws as my hex mill fixture.

Clamp the hex in the vise and cut one flat. Then turn in the vise and cut next flat until all six flats are cut. Then measure and take a finish cut.

And hopefully you come out with a part looking like this.

Next I cut the part down so about 1" of hex stuck out. Then back in the lathe and the larger diameter had a hole bored into it to fit the shaft were the clutch as attached to. Some Loctite was added and the part placed on the shaft.

And here is the completed fix ready for use.

Next will be a set of new soft jaws for the vise and the DRO has a few digits that are not working. Other than that the mill is working fine. I'm quite happy with the machine.

A friend of mine offered to make a rotary phase converter for me for $35. I couldn't turn that down. So I guess the 7.5HP rotary I was going to make will be on the back burner for now.

Also now I'm going to work on some tooling for my machines. I've noticed that I lack sorely on some tooling to make parts.

If your wondering where all this started take a look here:


A real nice fix there Bernd, you need a real good handle on there because the table takes a lot of shifting when you haven't got power feeds.  ::) ::) ::) :)

Just getting my own back for the workshop space poke.


I'll be making a better handle as time permits. Need to get a socket first.

Unfortunatley if I ever find a power feed I will need to get a new shaft because of the mod I did to this one. But then again I might just come up with something that will work. I realy like making minor mods like this.


Nice job there Bernd, guess you have two millers?

Thanks for showing us your way to hex a round bar, deff keep that on the back burner...



--- Quote from: Darren on November 26, 2008, 05:48:11 AM ---Nice job there Bernd, guess you have two millers?

--- End quote ---

Yes, I also have a Grizzly mini mill, plus the Sherline mill/lathe combo.

--- Quote ---Thanks for showing us your way to hex a round bar, deff keep that on the back burner...


--- End quote ---

Your welcome. Just like to share the knowledge to make things easier. :)

You can also use a square block to make square ends on round stock. If you need to hold smaller dia. parts you can make a sleeve out of aluminum, cut a length wise slot so it squeeses down on the part.



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