Help On How To Set Up And Make This Item.

Too many replies now for me to answer each post individually but thank you all for taking the time to think and reply, each has been appreciated a lot and I mean that !

Randy,
While I have a substantial amount of machining behind me I have never done any deliberate taper turning but isn't that what you will get with offsetting the tail stock, unless it was offset vertically, just thinking out loud here.

Just to clear up any misunderstandings I've sewn, the threads as well as the round spindle area are straight cut.

The several suggestions to bending was one of my first thoughts as well but it would take a at least (guessing) a 200 ton press to bend it which my shop is lacking by about 10 times over :)
It would also set up considerable areas of stress that is not wanted, I would think, likely that could be stressed relieved but that would be in the realm of a heat treat shop to answer.

Stuart, There are four mounting holes as shown in the picture but no other holes, these could be used to fixture.

Ken
 
I don't believe that the required accuracy or dim3ensions were mentioned.

If you start with an over-length bar and locate centers for each axle, you could turn your axles between the appropriate centers , leaving some extra length on your smallest diameters. When the axles are finished, use the centers as datum for setting up the milling of the rectangular block. Finish by cutting off the extensions and facing the ends of the axles.

That's a lot of mass swinging around in a highly unbalanced configuration though! Would the final machining be best done by grinding while rotating at a low rpm?
 
Tony Wells said:
There is a way to do what you want that is relatively simple. You will need a 4 jaw chuck if at all possible, and a mill to build a minor bit of tooling.
Click to expand...

Tony,
Now that's the kind of talk I like :D

I'm all ears if/when you have time to elaborate.


Ken
 
RJSakowski said:
I don't believe that the required accuracy or dim3ensions were mentioned.
Click to expand...

RJ,
Right now what is needed is a DIY setup/fixture method for machining on a manual lathe, once the method is found the final dimensions and tolerances can be dealt with as it is machined, the plan is to final OD grind after heat treat.

Thanks
Ken
 
2 degree wedges top and bottom facing opposite ways in a 4 jaw large enough to hold it. Otherwise a fixture like Epazella showed to fix the part into with out a 4 jaw big enough. The 2 degree wedges would be handy for set up that way also. Finish center section square, add the holes and use them to pin the wedges in place.

Wedges would need to be sized so the uncut end of the stock clears the back of the chuck jaws. I have a 14 inch 4 jaw and it is not big enough for the job so a pipe fixture is probably best bet. A slot could be cut in the pipe for the opposite end of the work piece to protrude through. That way smaller diameter pipe could be used. A weight could be attached to opposite side of pipe to offset imbalance.

Would take a large steady rest to hold that also.
 
randyc said:
Actually that was my suggestion, LOL, but your idea would work just fine. Whatever is easiest so that one of the centers is offset to produce the two degree angle :)
Click to expand...
I don't see how it can work with the tailstock offset. I think that just gives you a taper. I think you have to offest the headstock end.
Ken_Shea said:
Too many replies now for me to answer each post individually but thank you all for taking the time to think and reply, each has been appreciated a lot and I mean that !

Randy,
While I have a substantial amount of machining behind me I have never done any deliberate taper turning but isn't that what you will get with offsetting the tail stock, unless it was offset vertically, just thinking out loud here.

Just to clear up any misunderstandings I've sewn, the threads as well as the round spindle area are straight cut.

The several suggestions to bending was one of my first thoughts as well but it would take a at least (guessing) a 200 ton press to bend it which my shop is lacking by about 10 times over :)
It would also set up considerable areas of stress that is not wanted, I would think, likely that could be stressed relieved but that would be in the realm of a heat treat shop to answer.

Stuart, There are four mounting holes as shown in the picture but no other holes, these could be used to fixture.

Ken
Click to expand...

Putting together all the good ideas posted so far I came up with this while trying to get to sleep:

Mill the piece to the center dimensions.
Mill a 2 degree bevel on each end of the piece.
Mill a lip around each end perpendicular to the end wide enough for your four-jaw to grip.
You might also want to rough out the shafts so as to minimize the interrupted cutting
(but leave a block at each end for the four-jaw to grip).
Center drill each end.
Put a center in the tailstock. Do not offset it.
Clamp one end of the piece in the four-jaw, offset just enough to line up the center-drilled hole with the center
in the tailstock.
Do your turning on the tailstock end, leaving the block defined by the bevel and lips alone.
Reverse and repeat.
Cut off the blocks on the ends.
 
randyc said:
Problem with that idea is that the steady rest would have to be supporting the rectangular part of the workpiece. Maybe using a cat-head ....
Click to expand...
The rectangular part of the piece is held INSIDE the round fixture and the round fixture is supported by the steady. If the area to be machined is 3 inches long you leave that much sticking of the fixture so it can be machined. Obviously the dimensions of the fixture and the bolt placements would have to be scaled to the part being made. I made that fixture to machine the fuel rails on my boat engines. They are 14 inches long and have a totally random shape with bumps sticking out every where.

I had to go from this;

DSC_1081.JPG

To this

DSC_1103.JPG

Fixture in use

DSC_1077.JPG
 
randyc said:
epanzella, maybe I misunderstood your suggestion. Is the PVC tube intended to be a cat-head ?
Click to expand...
Sorry Randy, I should have been clearer. That's not PVC, it's black iron pipe. And, yes, the pipe is the cathead.
Ed P
 
Keep it simple. Put a center in each end. I recommend using a ball for a center in each end, with the one end in a 4 jaw. Using trig, calculate the offset needed to get the 2 degree needed. Then with an indicator on the horizontal jaw of the chuck, offset the center line the calculated value.
Use a dog to drive the part. The balls will keep the location at line contact on the ball.
 
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