FYI: Here is a link to the Vardex thread milling handbook. Includes a
link to downloadable thread milling software G-code generator.
http://vardexusa.com/vardex-pdf/Hand_Book_inch.pdf

Don Clement
Running Springs, California

Looks nice, most of my holes are 3/8-16 or smaller. $120 minimum per thread mill. I long for rigid tapping.

--97T--

I agee, if all of your threading is small size, then tapping is more cost effective than thread milling. Most of the many thousands of holes I thread are blind 4-40UN. For the small 4-40UN threads, I use a Balax forming tap with Procunier 1E tapping head on a manual mill. This should directly transfer to the Tormach when it is delivered in March. But I also have a need to tap blind large internal and external threads 3.25-16UN and M102-1 in 1/2" thick triangular shaped aluminum plate where thread milling should work great. Right now to make these large threads, I set up on a manual lathe using the reverse helix method and full profile inserts. Cost is more than thread milling inserts as a full profile insert is needed for each internal and external pitch along with an assortment of anvils for differing helix angle of a particular thread. Multiple passes are needed with the lathe. and I have to physically change two gears when switching from Imperial to metric on my manual lathe not just switch some levers... a real PITB. With thread mills the same insert will work on both internal and external threads. Thread profile is 100%. Although forming or roll taps produce a stronger thread in aluminum than a cutting tap because they forge the thread it is still not 100% thread engagement. No relief slot is needed with a thread mill and one can thread right up to a shoulder. Thread milling has many advantages and in some cases even less expensive.

I have gone ahead and sprung for the small thread mills for my Tormach. The results are fast, accurate, and luckily I have not broken one yet.

I'm just crying about the cost of the tool. For larger holes and OD threads, milling them is the optimum solution, especially where the shank diameter allows some strength in the tool.

--97T--

97T,

Whats the smallest size hole that you are thread milling?

Thanx
Wayne

I bought a range of sizes and tried out the 1/4-20 so far.

You can see them on Production Tool Supply catalog pg 338. Keep your hand over your wallet while viewing!

--97T--

any pics to show of the work guys?
thanks

One thing I've thought of, but haven't tried, is to use a the combination of a small boring head and a single point lathe internal threading tool to make a cheap threadmill.

-Jeff

One thing I've thought of, but haven't tried, is to use a the combination of a small boring head and a single point lathe internal threading tool to make a cheap threadmill.

-Jeff

A single point tool should work for thread milling. There are all the same problems with single point thread milling as there are with single point turning i.e. the form of the tool. I use full form topping or lay down inserts when thread turning because I get perfect thread form and have the ability to adjust for helix angle by using different anvils on the tool holder. With thread milling helix angle doesn't come into play does it? I have been wondering if single point thread milling is the only way to make multi-lead threads where one must make at least one pass per start or lead.

Don

recintly tried this to produce an odd pitch internal thread metric around 1.25"X5.5tpi did it with a double angle cutter in two passes part was aluminum makes nice threads for somthing you can't by a tap for I'v got a bunch of scrap nylon I try first to save materials My old Boss BPT has a caned cycle for spirel milling that work's great Kevin

Remember one single pt. tool will cut a lot of thrd. sizes.

here is the download link for both the lite and full version of tm gen software from vargus

http://www.vargus.co.il/tm_down.asp?num=3&title=10

Well I have a customer part that required a major design retrofit.

The power supply unit mounted to the back side of the front face - EXTREMELY Cosmetic face.

Anyway - this units were being retro fit under warranty for powersupply failure and it was decided to use a completely different powersupply which required all new mounting holes.

The faceplate is .315" (8mm) thick and the new holes required .28" useable thread in #6-32 without ANY deformation of the face on the far side.

I drill to .275" then spiral with a extended 3/32" 2 flute carbide to give me a flat bottom hole .295" deep. Then I threadmill in 2 passes. Works great.