KeithB
Resident Half Fast Machinist
I had a job come up that required drilling a 0.2" diameter hole into an aluminum part. The problem was that the hole was on the side of a rounded surface and required spotfacing to make a flat surface to start the drill in, otherwise the drill would wander off and not be accurately located. I could have used a 5mm end mill but none were available locally and I didn't want to wait for 2-3 days to get one so I improvised.
Years ago I had need for a small tool post grinder to grind a bore in a part on my manual lathe. I have a full size tool post grinder but it is a big, bulky, and heavy affair complete with a large 110V electric motor, a 6" wheel, frame, etc. I decided to make a tool holder for a pneumatic hand grinder. This was so long ago that I do not have pictures of the machining process to make the tool holder, but it required a milling machine to make the tongue and then a lathe with a boring bar to cut the interior surface to a curve that matches the OD of the grinder. The grinder is held in the tool holder with worm clamps.
It doesn't have a lot of power, you can't hog off material, and the wheel wear has to be dealt with, but for some things it is just the ticket. I found a used 1/4" HSS end mill (the end was still sharp but the corners and OD was worn) and chucked it up in the collet chuck. With the lathe running in reverse (to oppose the grinder's rotation) it only took a couple minutes to turn each end down to about 0.204". The mill will no longer cut sideways but it does great feeding straight down to mill a flat spot to start a drill.
I don't know if this will spark anyone else's ideas, but I can certainly see some uses for something like this doing gunsmithing work.
Years ago I had need for a small tool post grinder to grind a bore in a part on my manual lathe. I have a full size tool post grinder but it is a big, bulky, and heavy affair complete with a large 110V electric motor, a 6" wheel, frame, etc. I decided to make a tool holder for a pneumatic hand grinder. This was so long ago that I do not have pictures of the machining process to make the tool holder, but it required a milling machine to make the tongue and then a lathe with a boring bar to cut the interior surface to a curve that matches the OD of the grinder. The grinder is held in the tool holder with worm clamps.
It doesn't have a lot of power, you can't hog off material, and the wheel wear has to be dealt with, but for some things it is just the ticket. I found a used 1/4" HSS end mill (the end was still sharp but the corners and OD was worn) and chucked it up in the collet chuck. With the lathe running in reverse (to oppose the grinder's rotation) it only took a couple minutes to turn each end down to about 0.204". The mill will no longer cut sideways but it does great feeding straight down to mill a flat spot to start a drill.
I don't know if this will spark anyone else's ideas, but I can certainly see some uses for something like this doing gunsmithing work.