Coring question

[Stoney]

In practical terms what is the maximum length piece you can core with a gun drill? Most of the cored forearms I see are 12" plus the core material and I would like to end up with a cored piece somewhat longer than that. Chris's gun drills are approx 14"-15" but is that a maximum length, optimal length or an arbitrary length based on a 12" cored piece? I would be using a Cue Smith Deluxe lathe for the project if that makes a difference.

Thanks,
Stoney

 

[aphelps1]

I have both of Chris's gun drill bits, I think a core of 14 inches could be done by either diameter bit at one pass. As accurate as these bits are, I would think the wood could be flipped and cored from the other side to provide more length, although I have not tried this. 13-14 inches is about all I need when coring. I am using a Deluxe with no problems at all using these gun drills. Use a 1 inch starter hole as per the instructions and everything works great.

Hope this helps,
Alan

 

[BHQ]

In practical terms what is the maximum length piece you can core with a gun drill? Most of the cored forearms I see are 12" plus the core material and I would like to end up with a cored piece somewhat longer than that. Chris's gun drills are approx 14"-15" but is that a maximum length, optimal length or an arbitrary length based on a 12" cored piece? I would be using a Cue Smith Deluxe lathe for the project if that makes a difference.

Thanks,
Stoney

i dont know if the gun drill bit i use will fit in your lathe or not
i got it from sterling, it's 22" long and can drill 18"
it has a 3/4" shank, but they offer other sizes & styles

 

[QMAKER]

Coring Drill

In practical terms what is the maximum length piece you can core with a gun drill? Most of the cored forearms I see are 12" plus the core material and I would like to end up with a cored piece somewhat longer than that. Chris's gun drills are approx 14"-15" but is that a maximum length, optimal length or an arbitrary length based on a 12" cored piece? I would be using a Cue Smith Deluxe lathe for the project if that makes a difference.

Thanks,
Stoney

14 to 15" gun drills are fine for 12" pieces although mine are 18". The set-up,
which must be dead nuts on is the critical element. The 1" entry hole is essential, however I also make a 1" exit hole as well to eliminate break out.
I will give you one more tip: make sure the air you are using to blow the chips out of the drill is DRY. If it is not dry steam will build up in the hole and blow out the sides of some woods as well as injecting moisture into the wood. This is the reason snakewood is tough to core. Good luck.

 

[rhncue]

Gun drills can be special made to any length. When I got mine, 16 inch was the shortest but that included the mounting part and they went all the way to 48 inch as standard stocking lengths. My 16 inch will bore about 13 inch deep. If I had known that I wood have got one a little longer but the one I have has always sufficed. The base price for the 16 inch was around 120.00 and the price increased about 2.00 for each additional 4 inch. A buddy of mine bought one 36 inch but can't use it as his lathe isn't long enough. In a pinch you can always bore from both ends.

Dick

 

[Tony Zinzola]

I believe mine are both 18 inches. My forearms are 12" when finished, but I usually start wtih a 14 inch piece. If I have a really nice piece that is only around 11 inches, I can make it work too by coring the entire thing and using plain maple at either end. When the cue is done, the joint collar and ring take 1.1 inches on most of my cues and there is a .350" ring in the back.

How long of a piece are you looking to end up with?

 

[JoeyInCali]

Mine can drill up to 16 inches only.
So I'm thinking about this machine.

 

[patrickcues]

You can use Chris's drill bit to core with. All you do is core it from both ends. Then you can get at least 18"-20" easily.

 

[cueman]

14 to 15" gun drills are fine for 12" pieces although mine are 18". The set-up,
which must be dead nuts on is the critical element. The 1" entry hole is essential, however I also make a 1" exit hole as well to eliminate break out.
I will give you one more tip: make sure the air you are using to blow the chips out of the drill is DRY. If it is not dry steam will build up in the hole and blow out the sides of some woods as well as injecting moisture into the wood. This is the reason snakewood is tough to core. Good luck.

The pre-boring of the exit hole is some of the best advice I have seen about coring lately. My bits are made to core a little over 14 inches.

 

[Stoney]

How long of a piece are you looking to end up with?

Thanks to everyone for some good information and tips. I had considered "flipping" my workpiece for some extra length but did not know if it was realistic to expect good results from this method. From what some have said it doesn't seem to pose any particular concerns with setup being the key to a successful job.

I want to end up with a cored piece of approximately 14" which would give me the option of a forearm from 12" to 14". I can see a longer cored piece being usefull in some situations but will not cross that bridge until I come to it. For now, coring forearms and handles will provide all the new territory I care to explore at one time.

Regards,
Stoney

 

[QMAKER]

Coring

Thanks to everyone for some good information and tips. I had considered "flipping" my workpiece for some extra length but did not know if it was realistic to expect good results from this method. From what some have said it doesn't seem to pose any particular concerns with setup being the key to a successful job.

One benefit from boring from both ends is that you will find out if your set-up
is dead-on. If you feel a ridge where the holes meet your tailstock is off or
your headstock is not in true alignment with the center line of your bed.
I had covered alignment of both in a previous post. Assuming you are using
a .758 coring bit get yourself a piece of 3/4 test rod to check for wood movement (also covered in a previous post). Good luck.

 

[Grumpy]

In practical terms what is the maximum length piece you can core with a gun drill? Most of the cored forearms I see are 12" plus the core material and I would like to end up with a cored piece somewhat longer than that. Chris's gun drills are approx 14"-15" but is that a maximum length, optimal length or an arbitrary length based on a 12" cored piece? I would be using a Cue Smith Deluxe lathe for the project if that makes a difference.

Thanks,
Stoney

We use a Sterling brand gun drill & by flipping the wood we can drill 30 inches and we have not missed yet.

 

[Dave38]

Gun drills can be special made to any length. When I got mine, 16 inch was the shortest but that included the mounting part and they went all the way to 48 inch as standard stocking lengths. My 16 inch will bore about 13 inch deep. If I had known that I wood have got one a little longer but the one I have has always sufficed. The base price for the 16 inch was around 120.00 and the price increased about 2.00 for each additional 4 inch. A buddy of mine bought one 36 inch but can't use it as his lathe isn't long enough. In a pinch you can always bore from both ends.

Dick

I just ordered a new one from Sterling on Friday, 22" OAL, 3/4" shank, ground to work on wood, at .680 for $116 plus shipping. Give them a call, their real easy to work with. You just ask for Doug Holly, and he'll set you right. They can make it for your carrage holder, or for your tailstock. I went with the carrage, as it would be a pain to keep loosening and moving the tailstock every 1-2 minutes. It even comes tapped in the back for the air connection. I have 2 that were made for metal, and got them on ebay for cheap, but have had to modify the shanks from 1-1/4" down to 3/4" and ream and epoxy in an air connector, to much work. Now 1 got bent(don't recall doing it), and the other is a flat nose that needs a pilot hole all the way thru. It works, and got my feet wet, but I wish I would have just bought the right one the first time.
http://www.sterlinggundrills.com/product_prices_drills_2.shtml
There is about a 3 week lead time as they will make it just the way you want it. I have cored from both ends, as the 3/4" one is only about 12" depth and I usually core a little longer piece than that, and have had no problems.
Good luck and enjoy making sawdust with you weapon of choice:thumbup:
Dave