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DICKEYBIRD
03-12-2017, 10:35 AM
As usual, yet more tools had to be made to make another new tool. The center punch marks for the new CNC mill THK linear rail mounting holes need to be as accurate as possible. A job for custom made punches with a close fitting O.D. and the angle of the point being a little shallower than the drill to promote self centering.


http://i57.photobucket.com/albums/g227/DBAviation/Punch%20Usage_zpsvjhbkwdd.jpg (http://s57.photobucket.com/user/DBAviation/media/Punch%20Usage_zpsvjhbkwdd.jpg.html)

Eureka! A great use for the modified Darex grinder project posted earlier. http://bbs.homeshopmachinist.net/threads/68685-Some-stuff-I-recently-completed-BEFORE-having-the-stroke?highlight=stroke

Here’s a pic of the 1st 2 punches; others will be needed as the project progresses. They worked perfectly and the method will be used often in the future. An appropriately sized piece of O-1 was turned to rough size, heated as hot as possible with a propane torch & plunged into transmission oil. (Another post is coming about that near disaster.) The O.D.’s were ground to a close fit & the point angles ground to a bit less than the drills’ 135 degrees (about 140.) Conventional wisdom says tempering is needed but 40 holes each without chipping or breaking is good enough for me. They’re hard enough that (so far) there’s no blunting whatsoever; the points are crisp as new!


http://i57.photobucket.com/albums/g227/DBAviation/Punches%202_zpsjjx4p28f.jpg (http://s57.photobucket.com/user/DBAviation/media/Punches%202_zpsjjx4p28f.jpg.html)

http://i57.photobucket.com/albums/g227/DBAviation/Punches_zpsfni5vcla.jpg (http://s57.photobucket.com/user/DBAviation/media/Punches_zpsfni5vcla.jpg.html)

Here’s a close-up of the punch mark. It worked perfectly to help the drill/stand self center on the spot before drilling. Can’t get much better than that!

http://i57.photobucket.com/albums/g227/DBAviation/Punch%20Mark_zpsiucvywsp.jpg (http://s57.photobucket.com/user/DBAviation/media/Punch%20Mark_zpsiucvywsp.jpg.html)

mattthemuppet
03-12-2017, 01:13 PM
Very nice!

BCRider
03-12-2017, 01:26 PM
That made such a nice clean mark it's almost a shame to drill into them... :D

Making my own tools has been a lot of fun. It's annoying to need to side step for the time needed but it's always so satisfying to use them once back onto the main project when they turn a nasty job into a moment of perfection.

DICKEYBIRD
03-12-2017, 01:51 PM
That made such a nice clean mark it's almost a shame to drill into them... :D

Making my own tools has been a lot of fun. It's annoying to need to side step for the time needed but it's always so satisfying to use them once back onto the main project when they turn a nasty job into a moment of perfection.Thanks guys.:) I have to drill & tap lots & lots of accurate holes. I'm really glad that grinder was at the ready to do a good job. Only thing I noticed was the extra weight I had piled on the work head made it droop below level & the effect was a convex surface. A little tweaking of the head upwards with left hand while traversing the wheel with the right fixed it temporarily. Another thing to fix properly when I get an extra round Tuit.;)

Jaakko Fagerlund
03-13-2017, 12:54 AM
I have a set of such punches made up to 20 mm or so with lengths up to 400 mm. The material used was ejector pins from mold work, just needed grinding the end to a point.

MattiJ
03-13-2017, 03:03 AM
Looks like something I have been planning to make many times. Your idea of the shallow end angle seems good and the punches looks so handy that I think I'll have to actually make a set for myself instead of just dreaming. :rolleyes:

boslab
03-13-2017, 04:33 AM
Nice work, transfer punches were some of my most used tools,
Mark