# Mods to my Lathe Milling Attachment



## cfellows (Jul 18, 2010)

In setting up my lathe to cut helical gears, I used my lathe milling attachment to hold the helical gear cutting fixture. It easily allows me to raise and lower the cutter for different size gears and I can just as easily turn the assembly to the correct helix angle for the gear. However, I had to use an external measuring device like a protractor to set the correct angle. Today, I made a new base for the milling attachment and engraved angle marks to speed up and simplify the process.

I made the new base out of a square piece of 3/8" thick cold rolled steel. I turned the square into a disk about 3.5" in diameter. I then lashed things up on my mill / drill using a rotary table to engrave the lines in the edge of the disk. I ground a sharp V on the end of a 1/4" high speed tool bit and mounted it in a boring bar which I then chucked into the quill of my mill / drill. The base is mounted upside down on the rotary table and the tool cuts on the pull (up). Here's a picture of the setup:







Lacking a staking tool, I made up another assembly using my finger plate, two v-blocks, and a boring bar with a 1/4" hole in the end to guide the stamp. Not perfect, but it did a credible job.






Here's the finished disk, and the milling attachment on my lathe with the new base:


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## Dan Rowe (Jul 18, 2010)

Chuck,
The milling slide is the missing part I suspected you were using to cut the helical gears.

My 24 pin 5C indexer has marks for 3 and 4 divisions. You could mark your division plate that way or maybe 6 and 8 divisions as they are more likely combinations for gear work. 

Dan


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