Coring Issue....

blackhawk357m

blackhawk357m

AzB Silver Member
Silver Member
ok, I just picked up a set of coring drills. .312, .650, & .775. And I just tried to core my 1st piece of black palm. I center drilled the bp with the biggest center bit I have (about 1/2"). By the time I was done starting from smallest to biggest, the core hole is WAY off center, ruining my black palm. :mad:

Do I need to have a center drill bigger in diameter than the .775 bit so it doesn't shoot off center?


Thanks everyone,
Nathan
 
Don't use a drill bit for your pilot. Use your boring bar to make a hole that your coring bit fits into snuggly. Your bit will be centered and will follow that straight down the middle. If you are step drilling from size to size, you should consider using your boring bar to center each starter hole.
 
blackhawk357m said:
ok, I just picked up a set of coring drills. .312, .650, & .775. And I just tried to core my 1st piece of black palm. I center drilled the bp with the biggest center bit I have (about 1/2"). By the time I was done starting from smallest to biggest, the core hole is WAY off center, ruining my black palm. :mad:

Do I need to have a center drill bigger in diameter than the .775 bit so it doesn't shoot off center?


Thanks everyone,
Nathan
Click to expand...

Two things come to mind. Why not bore your center hole to size.

Have you taken a dial indicator to see if your wood is spinning straight?
 
WOW, I never even thought of boring it to fit. Yes it's spinning straight. Yes, it shows, I'm a newb. lol Thanks guys. <smacks forehead> been a long day
 
gun drill

I use an 11/16 core drill - .6876"

I center drill the piece then step drill with 1/4, 3/8, 1/2, 5/8. Then I bore the hole out so the gun drill just slips in the hole. I find that if I wipe a little cue wax on the head of the drill, it cuts smoother.

I use 40psi air through the drill.

Don't hog it out. Give the drill time to cut.

It usually comes out within 25 thou and most often almost perfect.

A Hightower lathe with a DC motor will not do it. Not enough power. The controller keeps tripping out. I added a 1/2 hp AC motor that I couple up just for coring.

Kim
 
coring

Are you air cooling it,if not the drill bit will heat and swell, causing a binding that could cause the drill to walk off center.the drill air also keeps wood chips cleared.
 
Are you step drilling the entire length of your wood? A good gun drill only needs a proper starter hole. The drill may wander slightly however when your core is glued in the wood is trued up to the core. This is why I always use the exit hole as my front.

Jim.
 
I core most of my cues with a .750 Sterling gun drill.
I use an 3/4" end mill and step drill 1.5" on both ends of the wood.
By drilling the exit hole when the gun drill reaches that area the hole does not get any bigger as well avoids any possible splitting issues.
 
The first thing that I wonder is HOW are you keeping the other end from moving around?

I use a fairly long piece of delrin with a 60 point on the end.

If you are that far off then your opposing end isn't straight.
 
pescadoman said:
The first thing that I wonder is HOW are you keeping the other end from moving around?

I use a fairly long piece of delrin with a 60 point on the end.

If you are that far off then your opposing end isn't straight.
Click to expand...

If the piece of wood is straight it won't move around Randy. I have my gun drill on my tailstock and never had an issue unless the wood is warped like a banana.
Also if your roundstock is the same diameter as the spindle hole of the lathe it will spin straight as an arrow.
I only core 13" long pieces as well and even if they are not the same size of the spindle hole of the lathe the coring hole is still straight.
 
I need to locate my blank collets for the steady rests. I was unable to find them the other day, but I have dozens of them with 3/8" hole or so I thought I had some left. You will only have to bore one hole ever for a starter and that is through the collet. Once you have a snug fit for the coring drill head going through the collet you can put your steady rest in front of the headstock and just start drilling. No starter hole needed. I made my self this and cored a bunch of handles. Just drill a little in one side then spin it around and drill all the way through.
 
cueman said:
I need to locate my blank collets for the steady rests. I was unable to find them the other day, but I have dozens of them with 3/8" hole or so I thought I had some left. You will only have to bore one hole ever for a starter and that is through the collet. Once you have a snug fit for the coring drill head going through the collet you can put your steady rest in front of the headstock and just start drilling. No starter hole needed. I made my self this and cored a bunch of handles. Just drill a little in one side then spin it around and drill all the way through.
Click to expand...

Definately gonna try this later today!

Thanks again everyone, you all are top notch :thumbup:

Nathan
 
I just make the pilot hole about 1 inch deep.

Kim

Sent from my SAMSUNG-SGH-I727 using Tapatalk 2
 
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I don't pilot hole the exit and I never have had a problem.

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Chris

That sounds way too easy. I am going to try that.

Thanks

Kim

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You need to bore a starter hole the exact size of your drill. Gun drills do not work off the center like conventional drill bits. They have to have something to follow and if you get off to a bad start you end up with a worse finish.

I wrote a tutorial here:http://www.jimboarmy.com/phpbb3/viewtopic.php?f=32&t=6097

Here are a few highlights.

IMAG0358-1.jpg


IMAG0359-1.jpg


IMAG0360-2.jpg
 
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My HT lathe headstock has a rear chuck.

If u don't have a rear chuck or your piece is short, center drill the rear of the piece and use 60 degree dildo in the back to keep the piece straight. Drill all but the last 2 inches then turn it around and finish.

Kim

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