Thread milling on manual milling machine

[giangthetool]

Hi everyone,

This is my homemade tool, I use it for doing thread milling on a manual milling machine.

The "device" uses a "nut and bolt" set for creating the thread cutting motion. Each "bolt and nut" set can be used for milling one pitch value when doing thread milling, and the diameter of the thread can be variable, as long as they have the same pitch. Also, it can be used to cut external and internal thread.

You can change the "bolt and nut" set to change the pitch.

The prototype version I made on this video is for demonstration and information purpose only.

It can only work on soft materials, because of the low rigid, low precision of the components and hand operation (quite dangerous also).

Have you ever made something similar, but in a larger scale?

 

[rklopp]

See about a Vetcoa rotary table. That uses the same principle.

 

[lucky7]

Deckel FP2 manual mentions a way to use the spiral milling attachment to threadmill. I haven't done it.

L7

 

[rklopp]

Z0
G41 G46 A0.3 X1 Y0.5 G1 G60 M61
G9 G2 M71 W2160 G90 I0 J0 Z-0.3
G40 G46 A0.3

is way easier!

 

[EmGo]

Or just buy a Lees-Bradner thread mill ....

 

[Cole2534]

Or just buy a Lees-Bradner thread mill ....

Do you suppose those are just floating about in Vietnam?

 

[FredC]

Interesting approach. If you have a lathe to build the parts might be a lot easier to make a live spindle for the lathe and mill threads there. A similar fixture using a ball bushing could be a lot tighter with less friction on the manual mill.
A toothed sprocket could allow you to drive it from a safer distance.

Thanks for sharing even though I would never need that device, principals might be utilized elsewhere.

 

[EPAIII]

Interesting. But why use thread cutting dies instead of an actual nut. The accuracy of the thread pitch will be primarily determined by the external thread of the screw that runs in that die/nut and the use of an actual cutting tool there will only allow that external thread to be shaved down over time, giving a looser fit and generating inaccuracy. Yes, I know that a threading die is not supposed to do that: they do not have the proper clearance for it. But in the real world, over time and many uses, they will.

I would suggest making actual nuts, possibly with brass or bronze and using a good quality threaded rod for the matching, male thread.

 

[EmGo]

Do you suppose those are just floating about in Vietnam?

Yup. Look on Taobao. China is right next door, plenty of cheap stuff readily available. They can trade for six endangered tiger penises or something.

 

[giangthetool]

Interesting. But why use thread cutting dies instead of an actual nut. The accuracy of the thread pitch will be primarily determined by the external thread of the screw that runs in that die/nut and the use of an actual cutting tool there will only allow that external thread to be shaved down over time, giving a looser fit and generating inaccuracy. Yes, I know that a threading die is not supposed to do that: they do not have the proper clearance for it. But in the real world, over time and many uses, they will.

I would suggest making actual nuts, possibly with brass or bronze and using a good quality threaded rod for the matching, male thread.

Yes, you are right. It better to make an high precised nut and bolt for the guiding. I just use a die because it's available at that moment, and I found it fit with the bolt better than normal nuts I found on the market, so I took the die for principal purpose.