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View Full Version : Another low cost rotary broaching tool



PaulT
09-24-2011, 06:06 PM
I really liked Mike's shop made rotary broaching tool design he documented a few days ago, simple yet very elegant.

Unfortunately too much work for me to pull off right now though but a commercial tool is also not in the picture because of high cost.

Inspired by Mike's design I realized that if you already have an Aloris type quick change setup there is another way to go using low cost components, not as clean as Mike's design but faster to pull off at a little higher cost.

The starting point is quick change boring tool holder, like these import ones:

http://www.shars.com/product_categories/view/4130205/Heavy_Duty_Boring_Bar_Holder_4__41

This the body for the tool.

Now you just need to fabricate a rotary tool holder, turning it so the extended body is a close fit in the boring tool holder and with a shoulder on it that will sit flush against the front of the boring tool holder and will take the thrust.

Drill and bore the front end of the holder for your rotary cutting tool, clamped with a set screw. I don't have time to make the rotary tool so I'll get one from these guys:

http://littlemachineshop.com/products/product_category.php?category=1274803839

Use a thust bearing like the one below between the front of boring tool holder and the shoulder on the rotary tool holder:

http://www.mcmaster.com/#thrust-washers/=e7fqp3

To set it up, oil or grease the shaft and thrust bearing and get the height set and locked using the height adjuster screw on the tool holder. Then use your compound to set the tool angle to 1 degree, center the tool in the X plane and you are ready to go.

Paul T.
www.power-t.com