Threadmiling Question

[richardsalzman]

I just tried my first attempt at thread milling a 1/4-20 thread on an aluminum rod.  While the threads work quite well, under a magnifying glass it looks like chatter.   I noticed this because the threadmill was making a bit of noise while machining.

Any idea as to what is causing this.  I experimented with lighter passes but still got what I think is chatter.  Here are some images and details:

[Laurens-3DTechDraw]

Generally there is a lot of contact area for a small tool, so often there can be chatter. Play with your RPM a bit, lowering it most probably helps.

[richardsalzman]

Thanks... Is there a way to make it start cutting at the bottom and work it's way to the top? 

[programming2C78B]

You should only (end)mill down to the bottom of the threads before cutting them, then continue machining your screw.

Split your toolpath up and do a final cut with a .005" WOC. Everything will be ok then. 

[richardsalzman]

Thanks... I will give it a try. 

[rosie_lucas1]

Hello @richardsalzman, 

Just checking in to see if you have had time to try @programming2C78B's suggestion?

If so and it helped, please consider clicking the "Accept Solution" button. Doing so helps others in the community find answers to similar issues.

If your question still needs more attention, feel free to reply here with an update. This way, other members can jump in with further suggestions or guidance to help you move forward.

All the best,

Rosie | Community Manager

[Laurens-3DTechDraw · Accepted solution]

You can change it from climb to conventional cutting to start at the bottom instead of the top for outside threads.

[richardsalzman]

Thanks!  I reduce the rpm and order of operations a bit and got very nice results.  

The folks that make the threadmill told me you can reduce chatter by staring at the bottom and working toward the top.  I will give a try for fun.

Thanks for your help!

Richard

[salvadore.bertolone]

what laurens said, but you need to consider the limitations of the tool and machine, its single point, and straight cut rather than helical cut, and sticking way out of the tool holder.  also consider the speed of the motion control of the machine, is that a tormach?

[richardsalzman]

Hello Salvadore,

The machine is a Tormach 1500MX.  I reduced the speed from 9720 to 9000 rpm, reduced the stick out quite a bit and got very nice results.  Virtually no chatter.  I did not try changing from climb to conventional but the folks at Melin Tool seem to think this will dramatically reduce chatter on longer thread lenghts.

Best... Richard