Bob Willing

I need a brad point drill bit that is stepped from 7/8" to 3/4". Any place to buy or do I need a machine shop to grind one down. I want to use for making goose calls. The over all length of the bit needs to be at least 8" long.

Bob Wingard

Can you find a counterbore that will do that operation in the metal-working trade stuff ??

TS3660

You can take a 7/8 and grind 1/16 off each side. Do you know how to do that? Just keep it centered with calipers or mics and it should be fine. Make sure you keep the cutting edge at a slight positive rake on the 1/16 ledge.

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Bud

"Capitalism is the unequal sharing of wealth: Socialism is the equal sharing of misery"

phinds

I think Bud is talking about a spade drill bit, not a brad point. Is spade bit really what you meant? That sure will be a lot easier to deal with than a brad point bit.

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phinds
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www.hobbithouseinc.com/personal/woodpics/

woodnthings

but could you drill the larger size hole first, then slip a tube inside that which has the inside diameter of the smaller hole which would center the bit. It's a 2 step process but short of a custom ground bit seems like it would do the trick. I also don't know if you are using spur or brad point type bits, but I think they would be the best for this application rather than a spade bit. bill

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Never stand directly in front of a horse or tablesaw that's running!
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

skymaster

7/8 forstner for counterbore, use the center point at bottom to center the 3/4 bradpoint and have at it.

Bob Willing

As I mentioned the application is for goose calls and a brad point bit. Spade bits will never give the accuracy that I want they drift off center very easly. I have gone the forstner/brad point way but the trick is getting it on center at the bottom of the hole. I know they make step drill bits for pen making for a lot of the specialty pens.

I guess I will contact a local machine shop because I want ever thing to be centered.

Texas Sawduster

Try these guys to see if they have what you need.
http://www.wlfuller.com/html/wood_sc...ep_drills.html

Bob Willing

Thanks

I sent them an email!

GerryB

Bob,
Have you considered a tapered reamer?
Regards
GerryB

Bob Willing

That's a good idea but I'll bet a tapered reamer is very expensive in a 3/4". I talked with my machine shop friend and have ordered a 7/8" brad point bit to be modified. Let you know what happens in about a month.

woodnthings

Then bore the large hole first with the brad point, I don't know how deep, until it changes to 3/4", then change bits, keeping it centered. Like I said a sleeve of plastic or aluminum will insure the smaller bit stays centered if it won't follow the pilot left by the 7/8". Your problem is the hole is very deep and brad points don't normally come that long, but I have some. I check to see what brand they are. bill
I found these on amazon Amazon.com: MLCS 9150 12-Inch Extra Long Brad Point Drill Bit Set, 7-Piece: Home
Improvement

Here's another source, see stepped drills at the bottom of the list: http://www.advantage-drillbits.com/bradpoint.html

__________________
Never stand directly in front of a horse or tablesaw that's running!
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

Bob Willing

I have the MLCS 5 pc set 9/16 to 1", but I ordered a 7/8" one from Roclker. They have any size individually. The 7/8 will be modified by a machine shop.

I will email your last suggestion.

Bob Willing

Receive the bit from Rockler today and it is really nice and long 8" inches about 2" longer than the one in the 5 piece set from MLCS. The drill bit looks like it is better quailty than MLCS.

Bob Willing

I got a quote from your suggested source and to have one made the price is $230.00 for one drill bit. Guess I will go wit h my local machine shop.

John in Tennessee

Or give me your address and I'll mail you one.

Bob Willing

"OK, "OK"...I am drilling a hole through 31/2" if wood with a 3/4" bit that will go all the way through and the upper step 7/8" only is 7/8" deep. The step drill you see on HF will not acomplish this.