Author Topic: SINGLE PROFILE THREAD MILLS  (Read 2738 times)

Offline tlagnhoj

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SINGLE PROFILE THREAD MILLS
« on: May 28, 2011, 10:47:01 PM »
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« Last Edit: May 10, 2012, 06:05:43 PM by tlagnhoj »

Offline JFettig

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Offline j_blankenship

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Re: SINGLE PROFILE THREAD MILLS
« Reply #2 on: May 31, 2011, 08:48:03 AM »
I too recommend the Harvey cutting tools for must stuff, but their double angle cutters are not true thread mills. Their cutters are ground to a point instead of being properly truncated - which would be a flat for ID threads. The other thing that makes them miss the mark is that they are solid carbide up until 3/4" I believe - so when buying a tool for a 1 or 2 time use I will get Micro100 tools. The Micro100 brand uses a steel shaft with a carbide head brazed on after the first size, which is 1/4",

If you need single point threadmills for volume production the PH Horn indexable system works very well, there is just a higher initial cost to buy the holder (which is the shank all the way down to the head which is replaceable).

www.micro100.com
www.hornusa.com

I buy both of these brands from Bass Tool in Houston, which stocks everything imaginable it seems most times and their pricing is leading the pack.

www.basstool.com

Regards,
John

Offline kingjamez

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Re: SINGLE PROFILE THREAD MILLS
« Reply #3 on: June 28, 2011, 05:49:07 AM »
I just used this internal threading tool holder to thread mill an AR-15 buffer tube. It took a bit of trial and error, but I eventually got it dialed in and it made perfect threads. It won't work well for small internal threads, but for anything ~.6" internal and all external threads it works well.

http://www.shars.com/products/view/7807/Internal_Threading_Toolholder_38quot_Shank_for_14quot_Insert . Not bad for $27.50

-Jim

Offline j_blankenship

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Re: SINGLE PROFILE THREAD MILLS
« Reply #4 on: June 28, 2011, 08:26:41 AM »
That is a good price for that holder! The insert is called the "lay-down" full form style, and the extra benefit with those is that they are also used on lathes for threading in a lathe holder - so your tooling investment is less than if you were to buy inserts specifically for each machine.

Edit:
>> Check that - are you sure that it created "perfect" threads? I'm not sure that the inserts are relieved with the correct clearance angles for threadmilling. I didn't dawn on me immediately before I commented. A threadmill's tooth form is not the full shape of a thread profile, the rotation of the tool makes it cut a nearly correct thread but not quite. Using a full form insert for threadmilling will overcut the thread, leaving a gouge essentially on the flanks.
« Last Edit: June 28, 2011, 08:34:51 AM by j_blankenship »

Offline kingjamez

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Re: SINGLE PROFILE THREAD MILLS
« Reply #5 on: June 28, 2011, 10:41:21 AM »
j_blankenship :
You know, I probably should not have used the word perfect. I don't know that for certain. My result was that I got a nice tight thread on the AR buffer tube and it seems to have worked well enough for this purpose.

How can I test to see how well the thread profile got made?

I'm also not quite following you on the profile problem, any chance you could illustrate that for lay people like me?

Offline tlagnhoj

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Re: SINGLE PROFILE THREAD MILLS
« Reply #6 on: June 28, 2011, 11:33:51 AM »
DELETED BY Tlagnhoj:
« Last Edit: May 10, 2012, 06:06:00 PM by tlagnhoj »

Offline j_blankenship

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Re: SINGLE PROFILE THREAD MILLS
« Reply #7 on: July 07, 2011, 10:35:38 AM »
Sorry for the slow reply, the 4th of July is my favorite holiday and I take my screwing-around-and-not-doing-anything pretty seriously.

That tool holder is meant to be used on a lathe and although it may work for some applications the carbide tool itself is not intended to used while rotating.  There is no relief on the carbide tool.  The front edge will cut a very nice thread profile as it first enters the material but as it rotates the back edge comes in contact as well.  In the buffer tube of an AR I doubt that it would be a big issue since the aluminum will give a bit.

Anyway, what he said - most of it anyway. The tool will cut the profile and the inward rotation, but then on the continuing rotation out of the cut it will cut the thread straight instead of being relieved at the pitch angle of the thread - true threadmills have this relief ground into them to not cut where they shouldn't (they don't make perfect threads either). I don't agree with the concept of the aluminum giving a bit in relation to the cutter, if that is what was meant.

The way for an average joe to check the thread shape is to cut a test piece and then section it so you can check the thread across the side. But if the threads you've made work for you and you're using them on low stress joints then go with it I guess.

Regards,
John

Offline tlagnhoj

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Re: SINGLE PROFILE THREAD MILLS
« Reply #8 on: July 08, 2011, 10:50:49 PM »
DELETED BY Tlagnhoj:

« Last Edit: May 10, 2012, 06:06:24 PM by tlagnhoj »