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9/19/2017 7:27:10 PM
Posted: 1/13/2006 12:57:00 PM EDT
Drilling the hole for the spring and detent for the front upper to lower pin has been my nemesis. I'm one for three right now. The lower is too long to fit in my Mini mill standing on end, so I have to use the drill press. I've center punched the start point, etc. and started the hole with the bit as far up in the chuck as possible to limit flexing and walking, but I'm still having trouble getting the piece clamped well enough to keep from moving during drilling, and it's been a bear getting the hole to stay centered and straight. Any advice or tips would be MUCH appreciated!

P.S. to salvage the two that got goofed up, I milled off the raised rib area back past the end of where the detent spring bottomed out and I am going to try tig welding a piece of 1/4 inch aluminum rod, same alloy, ground flat on a side to match the profile of the rib, to the area where the rib used to be. In essence I'm making a replacement rib. I may even make up the piece pre-drilled before I weld it in place.
Link Posted: 1/13/2006 1:11:08 PM EDT
Ive never had that much trouble. You should be able to hold it by hand and drill it although it is best to clamp it down. Are you sure your drill bit or chuck isnt bent?
Link Posted: 1/13/2006 1:14:24 PM EDT
I' m pretty sure the drill press chuck is true. Could be I just had a couple of bad bits in a row, though I used new the second time just in case. Maybe I need stronger glasses and a better light source too. It's hard to see that spot once it's clamped under the drill head!

What kind of vise do you use on your drill press to hold the piece?
Link Posted: 1/13/2006 1:20:20 PM EDT
In true Wecsog fashion I did the last one held by hand on my mill.

Is the drill press table a true 90 deg from the chuck? also has the rear of the lower where the stock fits been milled true? If not these could be causeing a slight angle which will make the drill bit want to walk.
Link Posted: 1/13/2006 1:30:56 PM EDT
I'll check those things. Thanks for the suggestions.

Any comments on my proposed 'fix' for the other ones? I figure it's not a stressed part, so as long as the replacement piece keeps the detent pin in the right place it ought to be OK.
Link Posted: 1/14/2006 6:28:05 AM EDT
Your fix sounds like it should work.

You could have a pice of aluminum that extends past the pivot pin hole that is drilled and taped 1/4-20 and use a 1/4-20 bolt for the front take down pin.
Link Posted: 1/14/2006 4:25:25 PM EDT
Make sure your Drill Press is set at slowest speed possible and use the sharpest 3/32 bit you have or buy some new ones. Use slow feed w/ slow speed and make sure the table is tight and so is the vise. I like to use the Dewalt bits w/ the Pilot tips. Also make sure the surface of the detent area is flat, you may need to mill this flat as most 80%'ers need a little work. Good Luck and remember SLLLOOOWWWW going.
Link Posted: 1/14/2006 4:41:19 PM EDT
Brownells and others sell either a pivot pin with an internal detent or a screw together front pin. why not just use one of those
Link Posted: 1/23/2006 4:13:55 PM EDT
one or 2 works, RAY-VIN Read his manual on how to do it. It shows you how to make a jig to help there's blue prints and everything
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