- Joined
- Sep 22, 2010
- Messages
- 898
Here is some of the counterbores that we make up for our clients.
They utilize a saw tooth Forstner made by Milwaukee under the name "Selfeed Bits"
The first ones I used to make had the counterbore pilot fitted and welded to the bit, then the pilot was turned on the lathe to true it up after the welding distorion. This worked, but you were limited to one pilot size per bit and it was very dificult to sharpen the bits when they became dull.
The next generation counterbore, became a bit with interchangeable pilots. The 1-3/4" dia bit shown uses from 1/2" up to 13/16" pilots. The larger pilots are used in the bigger bits. Note that the Selfeeds are hardened steel and take some pretty fancy tooling to modify.
This system allows you to drill a hole for the bolt, then counterbore for the washer and nut, so they can be set flush or below the surface of the beam.
I like to use coolant when turning on the lathe as it keeps the work cool and helps with keeping dimensions accurate, not alwasy waiting for the part to cool so you can check the diameter, but boy does it ever make life interesting. Ever seen a person riding a bike in the rain without fenders. Well coolant on the lathe sprays the front side. LOL
Walter
They utilize a saw tooth Forstner made by Milwaukee under the name "Selfeed Bits"
The first ones I used to make had the counterbore pilot fitted and welded to the bit, then the pilot was turned on the lathe to true it up after the welding distorion. This worked, but you were limited to one pilot size per bit and it was very dificult to sharpen the bits when they became dull.
The next generation counterbore, became a bit with interchangeable pilots. The 1-3/4" dia bit shown uses from 1/2" up to 13/16" pilots. The larger pilots are used in the bigger bits. Note that the Selfeeds are hardened steel and take some pretty fancy tooling to modify.
This system allows you to drill a hole for the bolt, then counterbore for the washer and nut, so they can be set flush or below the surface of the beam.
I like to use coolant when turning on the lathe as it keeps the work cool and helps with keeping dimensions accurate, not alwasy waiting for the part to cool so you can check the diameter, but boy does it ever make life interesting. Ever seen a person riding a bike in the rain without fenders. Well coolant on the lathe sprays the front side. LOL
Walter