[Gundawg]

I have been making a pin for a part I make out of 5/16" 316 SS and drill a interference fit hole for a 1/8" x 3/8" dowl pin near the end of the pin at 90* to the length of the pin (in the side). The pin is first bent to a 90* angle short leg being 1.5" long long leg being 5.5" long the small pin in the side near the end of the long leg is indexed by the bent end in the vise the small pin in the same direction of the short leg.

I have been doing this one pin at a time in my manual mill with a screw machine length drill bit to allow doing the operation without spot drilling first. You can tell when the bit gets dull because it walks on the 5/16" pin.

I am now buying a CNC bed mill and would like to make some sort of fixture to hold multiple parts to perform this operation. I am stumped on the design if I could use a fixture to hold say 20 of these I could use a spot drill then a screw machine bit to do this. I drill batches of these pins 200 + parts in a batch. I would really like to speed this up. Any good cross drilling jigs I could look at would be great.

Thanks Mike

[lkenney]

I think that I would bolt a long roughly 1" or thicker by abot 7" wide piece of aluminum to the mill table and mill in "L" shaped 5/16 wide by 1/4" deep grooves and as many as my chunk of aluminum would hold. I would hinge a hold down plate over the short legs and part of the long legs, secure with cam lockdowns of some kind through slots in the hold down plate. Using quick change tooling, I would first Centerdrill and then stub drill the pin hole. I would use colbalt tooling for both. Much less chance of a ruined hole and your drill will last longer. I would also look at the New Lube coolant system from SwiftCarb. This will extend your tool life by quiet a bit and avoid coolant splash with your open mill.

Your program for the slots will give you the dimensions for your drilling operations. The slot for the short leg could be just a groove lengthwise down the bottom plate. intersected with 90 slots for the long leg.

Hope this helps.
Lowell
360-432-2339

[Gundawg]

Thanks Lowell,
I probably was not clear the short legs must stick up vertical and be in the same direction the dowel pin hole is drilled in the main pin shaft. I think I may have a design that will work but it will take some time before my machine arrives to make the jig.

I am thinking milling a profile for each pin in a fixture plate then bolting another plate to the top with holes drilled to correspond to the profile slots then milled in half cutting the holes so they are open in the back or milling profiles there also, so that a pin can be slid in from the operator side of the fixture and a clamping bar to hold the pins tight near the end where the holes are to be drilled. I am not sure if my description makes any sense. I suck at drawing illustrations in Cad I am ok at making the toolpath drawings.

Mike