Thread milling

I am planning to start experimenting with thread milling. The thread form will be 20 tpi internal and external with a 2" nominal size in 6061 aluminum.

My CNC mill has canned cycles that can handle this chore. I wonder if any of you can tell me of your experience with thread milling. Is it better to use single point or multi point tooling? The cutters for thread milling are pretty expensive so I'd appreciate any tips about how to get started.

Ray

When I got into thread milling I started with an insert tool that way I could just buy inserts for the different pitches.I only use them on large threads like the one that you are looking to do. Thread milling is much more fun than the alternative.

What type of machine and what control are you using?


Take care
ARB

I use a Deckel FP4NC
http://www.me.uvic.ca/~rbrougha/DeckelFP4NC.jpg

It has a Grundig Dialog 4 controller with many canned routines including thread milling. I use Bobcad V18 to generate anything I don't want to write myself.

Ray

The single point tools are more versatile but slower. One can even be ground by hand with a single flute (REALLY slow) but in a pinch will do the job. For any kind of production, the insert type (big bucks) pay for themselves quickly. A four flute tap with all the flutes removed except one will work in an emergency.... the thread form will be a little loose, however, due to the helix angle.

Mark

Mark

Ray: On the Deckel if you use the canned cycle for thread mailling you must use a multi tooth tool. The suggestion of the "Verdex" cutter and holder is a good one. I have used these and they are quite good. The thread milling cycle on the Dialog 4 control will only make one turn and advance one pitchin the "Z". That means that you acn thread the length of the tool in one cycle. It is possible to do multi cycles but the error in lead where the two cycles overlap increases. I do single point threading all the time to special sizes and fits. I use a Sandvic threading tool (boring bar). I have SurfCam and it has single point cycles but i often do it by mdi. I use a polar milling move with a Z move combined to give the crrect pitch and length of thread. ID's and OD's , right and left threads are easily made with a few simple changes of sines on imput values. I use the cutter compensation to get the fit i require..if you like i can send you a sample program for the Dialog 4. Ross

My machine also has a caned cycle so I don't have to resort to programming.
I only do large thread by threadmilling so I have made a tool up for this.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/threadmill.jpg

Three various sized holders that take an insert from a Coventry Die head. You only need one insert out of a set and one pitch cuts all threads in that pitch.

Nice thing about this is the dies cn be had for peanuts at auctions or sales where the sets are incomplete or one is damaged. There was a load on ebay a while ago, about 120 odd pieces for about $30.00

This works very well and the tool can also double up as a tool holder for doing intrnal threads on the lathe.
I have been using this for quite a few years now and it works just fine.

John S.

Iscar has a free thread mill program that does all the work for you. Just cut and paste

try these guys, http://www.hornusa.com/ . or i've got some second hand tools layin around.thread miilin is one of my specialties
form your pictures, i would try a three flute insert.

Uncle Easy,

I've searched the ISCAR site but could not locate the thread milling program. Where did you obtain your copy?

Thanks,

George