KeithB
Resident Half Fast Machinist
One of the pieces we make for our main buyer is tailwheel pivot socket. We needed to make a fixture to hold the weldment in alignment while cutting an arc in one side of the thin wall tubing. We cut off and bore/ream the tubing pieces to size and cut a fishmouth on one end of the smaller piece. Our buyer has a guy that does the welding, and then they press in the plastic bearing/bushings. We get them back and cut the arc, which fits the nose of a spring loaded cross pin that lets the tailwheel pivot but forces it back to the center.
One of the handy things to have if you have a milling machine is 1-2-3 blocks. They are typically sold in pairs and measure a nominal 1" x 2" x 3". I mostly use them as parallels or riser blocks to get work up off the table top. They ones I use have 23 holes drilled in them, with almost half of the holes tapped to 3/8-16 and the rest are big enough for a 5/16 through bolt. (Also have a set of 2-4-6 blocks, same idea, bigger holes)
I knew this job was coming so I had time to think about how to hold and align the piece while still permitting access by the milling cutter. I had made a sketch using the block as a base and had to make a couple of pieces to attach to the block but it didn't take long to get everything together and start cutting.
When we first ran this job (pre-CNC mill) we had to mount the rotary table on the manual mill and crank the handle while reading a degree wheel. A long setup and essentially hand making each piece. With the CNC mill I just mount the fixture in the Kurt vise, find the center of the pin and the height of the tubing top and run a very short program that takes 15s from start to finish.
One of the handy things to have if you have a milling machine is 1-2-3 blocks. They are typically sold in pairs and measure a nominal 1" x 2" x 3". I mostly use them as parallels or riser blocks to get work up off the table top. They ones I use have 23 holes drilled in them, with almost half of the holes tapped to 3/8-16 and the rest are big enough for a 5/16 through bolt. (Also have a set of 2-4-6 blocks, same idea, bigger holes)
I knew this job was coming so I had time to think about how to hold and align the piece while still permitting access by the milling cutter. I had made a sketch using the block as a base and had to make a couple of pieces to attach to the block but it didn't take long to get everything together and start cutting.
When we first ran this job (pre-CNC mill) we had to mount the rotary table on the manual mill and crank the handle while reading a degree wheel. A long setup and essentially hand making each piece. With the CNC mill I just mount the fixture in the Kurt vise, find the center of the pin and the height of the tubing top and run a very short program that takes 15s from start to finish.