Wednesday, January 6, 2016

Threading Insert Tool Holder

Building a threading insert tool holder / boring bar to allow me to cut internal 1mm metric thread for the Ejector Nut for my Emco Maximat V10 Mill

Difficulty Level (Easy, Medium, Hard, Insane):

The process in itself was fairly easy, but because I had never built one of these it took a little fiddling around. Also, I learned that a sharp end mill makes all the difference in cutting O1 tool steel. Duh...

I was getting ready to build the ejector nut for removing the end mill holder of my mill, but had not yet had a need for a small (under 5/8" diameter) internal thread so the first thing I had to do is build a tool holder for one of my threading carbide inserts I had scored on kijij a few months back.

I took some 1/2" O1 tool steel that I had bought at Metals R Us in Dartmouth, NS a while back, cut off a 5" piece and milled a triangle out at the end to hold my insert. After matching up the tilt-angle of the insert with another boring bar, I milled off about 60 thou at the top and about 80 thou at the bottom, then drilled and tapped a hole for the screw that holds down the insert.

After it was all milled to size, I hardened it by heating it with my oxy/acetylene torch to a bright cherry red and quenching it in motor oil. After it had cooled down I sanded the surface to reveal the shiny metal and tempered it to a slight straw color.

After letting it cool down slowly I was ready to re-install the threading insert and cut the internal thread for the ejector nut.

Using some Dykem layout fluid to mark the line to mill
Milling the top flat
Marking the height of the threading insert
The milled, drilled, tapped and installed threading insert
A side view
Top view
Dialing in the shank to mill
The finished threading insert tool holder
Threading the internal 1mm metric thread
The finished ejector nut
Lathe and accessories
Angle grinder
Oxy/Acetylene torch
Tap & die set
Metal scribe

Dykem layout fluid
6" of 1/2" O1 tool steel
Internal threading insert
Old motor oil



Probably at least $100 bucks if not more

It worked pretty good. I ended up having to grind off some off the side of the bar but after that it worked great.


Heizi. said...

Aren't you forgetting a few steps.

GAB said...

Lovely... You should add pride and knowledge gained to your list.

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