Question about drilling "off center" holes in the SIDE of round stock.

Question about drilling "off center" holes in the SIDE of round stock.

Joined: July 24th, 2010, 1:44 am

March 12th, 2012, 10:46 pm #1

How would y'all do it?

Was wondering about making a replacement R9 end plug after betting a quote of $85-over $100 to buy a new "pot metal" one. The issue is accurately locating/drilling (or milling) the trigger group dowel pin holes in the sides of the plug since they are located "on a tangent".


The part I'd like trying to reproduce.
Last edited by nced1 on March 12th, 2012, 10:52 pm, edited 1 time in total.
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Joined: August 20th, 2006, 5:36 am

March 13th, 2012, 12:38 am #2

Or else some way to clamp it down REALLY securely. Depending on the hole size and where it is on the side of the round stock, I'd mill a small flat with an end mill, use a center drill to start the hole, then drill to size. If it's closer to the center line, you might be able to get away with skipping milling the flat. I'd say the trickiest part will be getting the hole location precisely located. But at $85-100 for a "factory" replacement, you can mess up a LOT of round stock and still come out way ahead !

BTW, I don't remember what you have for a mill, but if mine is bigger/heavier/more rigid and I can help out, let me know. Later.

Dave
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Joined: October 21st, 2001, 3:36 am

March 13th, 2012, 12:54 am #3

How would y'all do it?

Was wondering about making a replacement R9 end plug after betting a quote of $85-over $100 to buy a new "pot metal" one. The issue is accurately locating/drilling (or milling) the trigger group dowel pin holes in the sides of the plug since they are located "on a tangent".


The part I'd like trying to reproduce.
Clamp a 6" piece of faced stock in the vise, put your straightest rod in the drill chuck on the mill and bump it into the side of the round stock. Take a dial reading and swap it for a center drill. Dial in to the location you need using the reading you took with the drill rod/bit + half the rod diameter that you used. Start the hole and work your way up in drill bit sizes. A height gauge of some type can get a good measurement from the end of the stock, or just open the caliper and scribe with it.

Last edited by bigbore on March 13th, 2012, 12:59 am, edited 1 time in total.
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Joined: April 4th, 2005, 6:09 pm

March 13th, 2012, 2:07 am #4

How would y'all do it?

Was wondering about making a replacement R9 end plug after betting a quote of $85-over $100 to buy a new "pot metal" one. The issue is accurately locating/drilling (or milling) the trigger group dowel pin holes in the sides of the plug since they are located "on a tangent".


The part I'd like trying to reproduce.
You cannot drill on the side of a circle. If you can get an end mill the same size, make sure it is center cutting and go slow, lots of oil.

The long straight rod is a good idea, but a wiggler will be the best.

Jim
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Joined: December 3rd, 2010, 5:56 pm

March 13th, 2012, 3:28 am #5

I find it gives me consistant repeatable DRO readings. As soon as it 'barely' just touches a metallic-type edge it lights up so you can prolly see where I'm coming from. And they're cheap. Most of all and you're not gonna believe this for an inexpensive well-made electronic gadget, they're made in the U.S.A. of all places.

Dave

http://www.google.com/products/catalog? ... CFQQ8wIwAg#


http://www.travers.com/product.asp?Requ ... 57-062-027
Last edited by AKSevenDave on March 13th, 2012, 3:32 am, edited 1 time in total.
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Joined: March 2nd, 2009, 5:45 am

March 13th, 2012, 3:59 am #6

How would y'all do it?

Was wondering about making a replacement R9 end plug after betting a quote of $85-over $100 to buy a new "pot metal" one. The issue is accurately locating/drilling (or milling) the trigger group dowel pin holes in the sides of the plug since they are located "on a tangent".


The part I'd like trying to reproduce.
Drill the "tangent" hole while square then turn it round?

Only the wise read signatures.
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Joined: July 24th, 2010, 1:44 am

March 13th, 2012, 2:22 pm #7

Thought about that, however that would create a MOUND of chips.....LOL nt
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Joined: July 24th, 2010, 1:44 am

March 13th, 2012, 2:30 pm #8

How would y'all do it?

Was wondering about making a replacement R9 end plug after betting a quote of $85-over $100 to buy a new "pot metal" one. The issue is accurately locating/drilling (or milling) the trigger group dowel pin holes in the sides of the plug since they are located "on a tangent".


The part I'd like trying to reproduce.
I guess that I'm a bit "red faced and embarrassed" to read the obvious tip of milling a flat spot first to give the center drill a square starting surface.....thanks for the help!!

When reaming a hole to size, will the reamer generally center itself in the drilled hole maintaining the position relative to another hole that will be reamed?
Last edited by nced1 on March 13th, 2012, 2:31 pm, edited 1 time in total.
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Joined: June 16th, 2009, 7:43 pm

March 13th, 2012, 3:20 pm #9

Make sure you use a split point drill for your holes as it helps to prevent the drill from wandering. I would recommend your drill diameter be a maximum of .005/.007 undersize to the finish reamer diameter for holes the size you are machining. I would machine the trigger block cut out after you've done your hole pattern. And to your immediate question...yes, your reamer should follow the centerline of your pilot hole, provided you feed the reamer slowly and the reamer has a tapered lead on the end. "Chucking" reamers have this larger taper that is desirable in you application. Be sure the spot face you mill is larger than your finish reamer diameter.

Edit BTW....make sure that when you are milling those interrupted cuts for your flats that you minimize your quill extension to cut down on excessive vibration at the cutter.

Edit #2... I would take your pattern dimensions off of the trigger block (hope that wasn't too obvious).

"Silence is the only thing that can hinder the Truth"
Last edited by jlucas50 on March 13th, 2012, 3:32 pm, edited 1 time in total.
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Joined: September 15th, 2000, 3:23 pm

March 15th, 2012, 11:07 am #10

How would y'all do it?

Was wondering about making a replacement R9 end plug after betting a quote of $85-over $100 to buy a new "pot metal" one. The issue is accurately locating/drilling (or milling) the trigger group dowel pin holes in the sides of the plug since they are located "on a tangent".


The part I'd like trying to reproduce.
I am working on a build now that uses off set holes on round stock. I have been milling a flat just as recommended here, and then spot drilling before starting with a drill bit, and it has worked like a charm.

Regards,
DaveG
See more picts @http://davegcustomstocks.com
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