9" x 1-1/4" hole drilled on a lathe

[Brian Kent]

What Forstner would you recommend?

I need to drill a 9" hole by 1-1/4" wide into walnut or sapele end grain. It is for a gun part for my brother-in-law.

I could get a Maxi bit with extender from Lee Valley. About $72 plus tax and shipping. Prefer not that much, but willing if I need to.

What other option is there for a difficult cut?

I also could do it in several steps, and/or from both ends with HSS.

Thoughts?

[Jamie Buxton]

Rip the blank down the middle. Mill channels up the middles of both halves. Glue back together. Turn the outside. No long bit required.
You can make the channels with a table saw, or a router.

[Brian Kent]

Brilliantly obvious.

[Rich Colvin]

Here's a great YouTube video of a guy doing just that.

https://youtu.be/NCrETz4RTyM

Rich

[John K Jordan]

I need to drill a 9" hole by 1-1/4" wide into walnut or sapele end grain....

If you do decide to drill I've had good success with deep holes by directing a stream of compressed air into the hole while drilling. Cools the bit, but more importantly, keeps the chips cleared out. I have a set of carbide Forstners I prefer for deep holes.

JKJ

[Paul Williams]

I start the hole with a forstner bit the desired size. Drill about 1/2 inch deep. Just deep enough to guide the bit by the sides. Then I use a 1 inch auger bit that is 12 inches long to get the depth. Then I go back to the original forstner bit with extensions to bore to final diameter. If the final hole is going to be much larger than 1 inch I use a forstner bit sized between 1 inch and the final size. Start that bit after the initial bit so that you will have sides to guide the bit after the auger bit. I have gone a foot deep with this method. Not sure how much the final bit wanders off center. In my case it didn't matter.

[David Delo]

Brian,

Not sure about the LV extender but the 6" extender I have with a 1 1/4" forstner bit would allow me to drill a hole just shy of 9.25" deep before the Jacobs chuck would hit the piece. If your just needing 9" and not any more, you should be okay. Just check out your dimensions beforehand.

I usually drill 10" to 13" deep holes in the vases I make and have gotten away from using extenders. Something always ended up spinning. Either the extender shaft spun in the chuck or the MT2 taper wanted to spin in the tailstock. Went to the Carter Strongbore system and never had a problem since. My pilot holes are 1 3/4" because I need that diameter to get the hollowing bar & cutter inside and have a little slop to manipulate the cutters. YMMV but works for me.
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[Kyle Iwamoto]

Does it have to be exactly in the center? A trick I learned is to drill the hole in the blank before turning to final thickness. Make a jam chuck to drive the piece, and put the other end back on the tail center. Centers the piece every time.
Irwin makes a ship auger bit that is real long. Start the hole with a sturdy bit and you have pretty good chance that the auger will be relatively straight.

[Marvin Hasenak]

Drill one end as deep as possible. Then take a 2x2x12 scrap blank and drill and tap for your lathe spindle, turn it to the diameter of the hole in the blank. This has to be an almost perfect fit, as close as possible. The blank with half the hole should fit on the shaft of the scrap spindle you made, then drill from the opposite end. If the bit length is too short, MLCS has a 5" extension that is reasonable.

[John K Jordan]

Drill one end as deep as possible. Then take a 2x2x12 scrap blank and drill and tap for your lathe spindle, turn it to the diameter of the hole in the blank. ...

I use that method a lot but instead of tapping I hold the wood with a chuck then turn it to fit.

I make jam chucks like that to use on the tailstock end too, but tap that 3/4"x10tpi. I fasten that piece on a live center, lock it with a piece of wire to keep it from spinning, and use it as a drive center to turn the jam piece. As Kyle mentioned, if you hold both ends this way then finish turn the outside, it will insure the outside is precisely concentric with the thru hole even if the hole was bored off axis. Good for kaleidoscopes!

JKJ

[Joe Meirhaeghe]

I us the Colt Maxi cut bit you mentioned mounted in my 1" diameter Advanced Lathe Tools boring bar to regularly drill 1 1/4" dia. end grain holes often 16" or so deep. Great drill bits, expensive yes but the best bit's I've ever used I often recommend them.

[robert baccus]

I guess I really am a cheapie. I do a lot of vases and urns in the 10" to 18" height and commonly use a Artisan 10" extension shaft and a 2" HF forstner bit for a pilot hole. Don't you just hate name droppers.

[Kyle Iwamoto]

I guess I really am a cheapie. I do a lot of vases and urns in the 10" to 18" height and commonly use a Artisan 10" extension shaft and a 2" HF forstner bit for a pilot hole. Don't you just hate name droppers.

Well, I use that aforementioned (not wanting to drop the name brand) Irwin ship auger bit to drill a deep pilot....... Gotta be cheaper than an extension shaft and a forstner. AND I have a 3 pack of them. I'm REALLY cheap. IF you do decide to use that auger bit, start with a cheap (1 buck for a clearance Home Depot set) spade bit the same size. If you start very slowly, even a spade bit can start fairly straight. In case you guys didn't already know, spade bits are really easy to sharpen.

[Thom Sturgill]

One tool not mentioned is a gun drill. While I doubt you find one that size, they drill a straight hole and might make a great starter hole to keep the bore straight.

[William C Rogers]

One tool not mentioned is a gun drill. While I doubt you find one that size, they drill a straight hole and might make a great starter hole to keep the bore straight.

Trent Bosch used a gun drill in his hollowing presentation at the symposium. He just used a 3/8"