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View Full Version : How to cut wrench flats?



derekg
11-27-2009, 12:33 AM
Hi All,

I got another odd one. I need to make a fitting for my oil line on my turbo. Oddball size of 1/2-24 UNS thread on lower portion with 45 degree inverted flare. Upper portion is an AN -3 (3/8-24 with 37 degree flare). What I need is to cut wrench flats on a portion between the upper and lower. And now for the odd part. I have a lathe. I have a drill press with end mills. I have an X/Y table vise for the drill press. I have blind ambition with a dash of unrealistic expectation, so I'm ready to go. I was thinking of starting with 3/4" aluminum bar stock, cut to length, face the ends, then mark out 6 wrench flats on the ends, line up those marks with the top of the vise (match marks), and use that to set depth of cut. With my limited tools, is there another way?

Many thanks and Happy Thanksgiving.

Derek G

danlb
11-27-2009, 12:45 AM
If the part is somthing that will be threaded, then you can thread a commercial bolt into it. A jamb nut will keep it from rotating. Then clamp the bolt in the vice and you have a 6 way indexer. After each cut, loosen the vise and rotate the bolt to the next face.

Make sure you have a way to make the part the same height after each turn.

Dan

doctor demo
11-27-2009, 12:54 AM
The easy way would be to start with a piece of hex bar stock, then You can skip the wrench flat part of the machining fun.

Steve

derekg
11-27-2009, 02:10 AM
Thank you for the two great ideas. I didn't even know there was such a thing as hex bar stock. Like Kermit the Frog said, "It's not easy being green..."

Many thanks,

Derek G

Black_Moons
11-27-2009, 05:40 AM
you could probley put a single set of flats if thats enough with just a simple angle grinder or sander (messure at nasua to insure your grinding the two sides parallel and to a certen size to fit a wrench)
4 flats would also be easy, 6 flats is VERY easy to screw up by eye (at least, my brain dislikes 1/6ths of a rotation) so draw it out on the part before grinding.

Sometimes we don't need critical accuracy, and others just some test fiting will bring enough accuracy needed if you are careful enough.

J Tiers
11-27-2009, 10:09 AM
File them. You can fit them as you go along, and no special stuff needed. Files may be the most ignored tool.

A filing rest for the lathe will allow you to make them nearly perfect.