Internal Threading Tool And Flycutter

Ok, not trying to steal your thread, but here is a pic of the spot face I'm going to need to do.

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interesting! I can see how that would be tricky to set up. One way you could make a spot facer for that would be to turn a cylinder to fit the OD of the spot face, then turn the end down to fit the ID. Turn the other end to fit whatever collet you want it to go in (3/4?). Then mill 2 opposed 1/4in slots down the sides, ideally offset so that the cutting faces will be on the centerline. Add setscrews. Then you can grind 2 1/4in lathe bits and be able to position them for both depth (move them length ways along the tool) and cutting width (shim them out from the tool centerline) to tweak the cutting diameter.
 
That's a good idea. I'm gathering tools now for the project. I got a 1.75 end mill with a 3/4" shank off Ebay for $10 plus shipping. I'll use that to plunge in, then use my boring head for final diameter.

But again my biggest problem is fixturing it. I'm guessing the hole is probably 20 degrees positive in one direction, and the same in another direction.
My plan to get the hole perfectly vertical is to take a 2" piece of stock and turn a 3/4" spud on it to go into my collet on my mill, then turn the other end to fit tightly into the hole. I'll put a shoulder on it and it will bottom on the spot face, and I'll drill an tap that end and make a strap clamp I can put inside the housing to clamp it to the end of the rod. This will get the hole vertical, then I need to square it up in Y axis.

Next comes trying to design a fixture that will hold it tilted it to the right. That gets the face of the housing secure. Then the second fixture will both up to the transmission mounting holes with a forward tilt to it. The position needs to repeat accurately. What I'm doing is duplicating the hole you see in a housing in a similar housing that is cast for it, but isn't machined.

I hope my description isn't to hard to follow. If I can get the rod turned and mounted in the mill with the housing on it and take a pic, it will be much easier to understand.
 
that's tricky - I wonder how they would have done it at the factory? Are there any reference surfaces in the original that you could use, if only to make a fixture? Or once you have the new housing secured to the spindle with your spud, use jack screws to support the housing at the right angle then bolt it to the table?
 
mattthemuppet said:
I wonder how they would have done it at the factory?
Click to expand...

Use a 6 or more axis machine with articulating heads. :)

I would build a spud that fits the hole and the other end in a collet in the spindle. That would hold the housing in position. Then build up a fixture that bolts to whatever convenient holes you have available. Build the fixture from the bolt holes down. Bolt the fixture together until you can get it off of the machine and over to the welder.
 
Jim, I just need you to build that 5th axis we talked about and I can farm the work on this out to you :)

I'll make the spud as soon as I find a lathe to use. I don't have a 3 jaw for mine yet, just the 5C collet closer.

I have another housing I do and I attach it to a fixture plate that's bolted to a 6" angle plate. I ream 2 holes in the housing for accuracy, and they go onto 2 dowel pins on the fixture. I want to do the same thing on this one.

The spud will give me a perfectly vertical hole, then I'm thinking of bolting a plate onto the mounting holes on the housing where it bolts to the back f the trans. The I need to square it up and figure a way to attach it to the table parallel to X axis. I am considering making a large plate that will register on the T slots and have both the fixture plates parallel to X and Y on it. Then I just put the fixture on and it will be square, bolt it down, and dial in my origin point. It will cost more for materials, but will be much easier to set up that 2 separate fixtures.

I'm still thinking of how to do this. I have about 10 days off at Christmas and this is one thing I'm hoping to work on.
 
I think I know somebody with a lathe and a chuck;)
 
I'll take you up on that.

Would be nice to brainstorm how to make the fixture.
 
Went out to Jim's yesterday and got the spud made. We were looking at the housing and Jim came up with the idea of using the angle mount that came on the Acer mill head I got at the auction as a fixture. I had thought about an angle plate but a 12" one was expensive. So this will work perfectly.

The idea is to use jack screws with a swivel base to set the angle on the angle plate. So I'll just need to square the plate up, dial in a corner and go the the position where the hole needs to be machined.

I trammed the head in on the Kent today and used it to set everything up. I'm not using it right now, am waiting for the DRO to come in. So it's not a problem leaving the fixture on it while I order parts in to finish up everything.

The hole looks like it's about 16 degrees to the right, and with tilting the angle plate I can just rotate the housing on the plate to get my second angle. Started drilling the holes to mount the housing to the plate and realized I didn't have a 7/16" tap. So I'll find one and work on it tomorrow hopefully and order in the jack screws.

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that's a neat solution - it'll be fun to see the finished product!
 
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