Long Taper groove (thread) Can it be done?

[mikeyz3385]

 I recently just installed a index pulse card and now im threading everything thats round. Just for fun i thought it would look cool to turn a round aluminum bar down to a taper say from .250 OD to .750 OD by 2" long, and on that taper i wanted to add a perfect groove much like a thread. Is that at all possible? I know that the threading wizard has a taper option but i'm not sure exactly how to use it.

[Hood]

It should be possible to do but depends what you are meaning by a groove, if its a square edge and flat bottom then you may run into rigidity problems unless your machine is a big solid lump.
The taper is just the angle you require, if you put in a value then press the Post Code button you will see a representation of the path and you should see if it looks like it will be correct, might be worthwhile cutting air first just to make sure that it looks like its doing what you want to achieve.
Hood

[ostie01]

It should be possible to do but depends what you are meaning by a groove, if its a square edge and flat bottom then you may run into rigidity problems unless your machine is a big solid lump.
The taper is just the angle you require, if you put in a value then press the Post Code button you will see a representation of the path and you should see if it looks like it will be correct, might be worthwhile cutting air first just to make sure that it looks like its doing what you want to achieve.
Hood

Cut air???

This is not very productive.

Could not resist.

Hi Hood.


Jeff

[Hood]

Cut air???

This is not very productive.

Could not resist.

Hi Hood.


Jeff

 I beg to differ, its much more productive than smashing up your £150 threading tool I find
Hood

[RICH]

Jeff,
It's been a while since i fooled with this, but if you do threading using alternating flank cutting using a V shaped tool you could cut a groove. Actually it would be more like an acme thread.
You just adjust the X end to be  less than the depth of a large v thread. The alternate thread method willl minimise the load on the piece since it alternates between the flanks when cutting.
If your lathe is very accurate along with manny passes the root may have a finished appearance.
Have fun........
RICH

[mikeyz3385]

I will have to give it a try, basically the other day i had a hss cutter that i ground a small radius edge on it and cut a thread with .125 pitch. Came out lookin pretty cool , would be really nice for a handle for something. Then i got the idea to try it on a big taper.

[RICH]

I know that the threading wizard has a taper option but i'm not sure exactly how to use it.

The threasding wizard  will cut a tappered thread. One of the important inputs is the taper. The taper is defined as 1/2 of the total taper on the end of the piece.
You need to be carefull because the axis movement is along the taper and as such the initial movement ie; say 3 to 5 diameters to allow for acceleration will be along the taper and can be negative / cross the x=0.

I get a chance i will do a little write up on taper threading and put in the members docs. I was waiting for a friends backplotter to be refined to show the pathing of the code generated by the threading wizard.
No that i have that i can see what is really happening with the generated code.

Till Then,
RICH