Has anyone built a guide for a center drill.

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AllenH59
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Has anyone built a guide for a center drill.

Post by AllenH59 » Mon Jul 06, 2020 12:22 pm

Gentlemen: I have to drill both ends of a 4 shafts that are in the range of the max length of my lathe, and too big to go through the headstock. . I am considering making a guide and putting a bearing in it and drilling the ends with an electric drill. Knowing how hard it is to be the first to think of something, I suspect someone has thought of it before.. I suspect I can drill them faster and as accurate that way as I can by setting them in the steady and confirming that everything is lined up then drilling.. any comment would be appreciated.

John Hasler
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Re: Has anyone built a guide for a center drill.

Post by John Hasler » Mon Jul 06, 2020 2:34 pm

Are you going to turn the shaft between centers?

AllenH59
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Re: Has anyone built a guide for a center drill.

Post by AllenH59 » Mon Jul 06, 2020 2:50 pm

John Hasler;
I want to get the bearing surfaces nicely aligned with each other.. I have to turn bearing surfaces at both ends... I want the option to turn it between centers, but I have to do work on both ends, and so it requires they both be drilled. I have all the stuff required to spin it between centers.. I would like to have the option.

John Hasler
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Re: Has anyone built a guide for a center drill.

Post by John Hasler » Mon Jul 06, 2020 3:46 pm

If you are going to turn between centers (as you should) I think that would work fine as long as you take off more material than the error in the drilling.

whateg0
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Re: Has anyone built a guide for a center drill.

Post by whateg0 » Mon Jul 06, 2020 8:04 pm

Do you have a steady rest? I was going to build a fixture to hang off the end of my 10ee to face the end of some tubing that was right at the end of the bed. Ended up being able up use the lathe at the local maker space instead but I can see where it would be useful even if it lacks the rigidity to do any real work.

TRX
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Re: Has anyone built a guide for a center drill.

Post by TRX » Sat Jul 25, 2020 10:04 am

Back in ancient times there were machines that you stuck the end of a bar into and they centered and drilled it automatically.

You could make an end cap on the lathe, stepped to accept the workpiece and the center drill, and use a hand drill to make a centered hole.

pete
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Re: Has anyone built a guide for a center drill.

Post by pete » Sat Jul 25, 2020 8:53 pm

At one time there was a tool with an internal cone shape meant to do this type of job on a variety of shaft sizes. While I've not ever used that tool I suspect it's exact accuracy wasn't that good and having an already burr free and flat face 90 degrees to the shaft's length would be needed to get the best out of it. I remember seeing it in the older Enco catalogs but I can't recall it's name or what company made it. Your idea should work well enough. But you haven't provided enough information. How long are the shafts, diameter, accuracy required, what other equipment do you have access to etc. Within the limits of what my mill has between the floor and the tip of a center drill I'd just set up a couple of angle plates with any angle of V shape bolted to the table or a V block if one would work, clamp the shaft vertically and hanging off the side of the table then swing the head and indicate the spindle concentric to the shafts O.D. That's one of the big selling points of Bridgeport type mills is there versatility and just what they can be set up to do, but only if you've already got one. If all the shafts are the same diameter then the indicating obviously only has to be done once.Most of the other non Bridgeport type home shop sized mills can usually rotate the head so it's horizontal and looking down the X axis so that's another method.

Even a lathe milling attachment and the center drill held in the lathe chuck can be utilized for doing end work on shafts and it's one of the main reasons I bought a new one even while having a couple of mills. For longer shafts then some type of make shift support of it's free end would be needed with a milling attachment. Any of this just depends on what you already have. Being careful and using some magnification the standard centering head included with most combination sets, a center punch mark and hand drilling the end with a center drill in a hand drill should get you to within .010" or so of being concentric to the shaft O.D. It still boils down to just how concentric do you need as the initial starting point as far as the easiest or fastest method to do this and what you already have in your shop.

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Lew Hartswick
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Re: Has anyone built a guide for a center drill.

Post by Lew Hartswick » Mon Jul 27, 2020 8:28 am

TRX wrote:
Sat Jul 25, 2020 10:04 am
Back in ancient times there were machines that you stuck the end of a bar into and they centered and drilled it automatically.

You could make an end cap on the lathe, stepped to accept the workpiece and the center drill, and use a hand drill to make a centered hole.
I did exactly that a few weeks ago to center drill wood dowels . Made the "cap" on the drillpress.
...lew...

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Bill Shields
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Re: Has anyone built a guide for a center drill.

Post by Bill Shields » Sun Aug 02, 2020 2:33 pm

if you use a long guide bearing and an extra long center drill with tight clearances everywhere you should be OK
Too many things going on to bother listing them.

ChipMaker4130
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Re: Has anyone built a guide for a center drill.

Post by ChipMaker4130 » Thu Aug 06, 2020 6:31 pm

You've got 4 to do. If they're all the same, just set up the steady and don't change anything between parts. If they're not the same, well.... you've only got 4 to do. You'd have 'em done by now! In my opinion, nothing's broken/nothing needs fixing.

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