Question about Grizzly's 25mm banjo post hole

[Bill Jobe]

I know many, if not most, ream out the post hole on the Grizzly banjo to 1" so it will accept most other tool supports.
Some have reported using a 1" drill or core drill, others a reamer, still others simply opening it up with some kind of abrasive.
Do you continue to use the Grizzly supports as is or do you aquire a .020 sleeve of some sort?
If you use a sleeve do you make it with brass or do know where I can buy one?

[Tim Passmore]

Bill, I've just continued to use the Grizzly tool rest without any adaptations. It works just fine.

[Roger Chandler]

No adapters needed to continue using the original tool rest.

[Joe Shanaphy]

Roger and Tim ... am I correct that you're both saying that using a 25mm post in a 1" drilled banjo won't affect the performance of a 25mm post tool rest? I am asking since I bought a few Robust rests in 25 mm but am now re-thinking keeping that dimension and going to 1" in order to fit other aftermarket accessories ... without giving up my Robusts!

[Roger Chandler]

Roger and Tim ... am I correct that you're both saying that using a 25mm post in a 1" drilled banjo won't affect the performance of a 25mm post tool rest? I am asking since I bought a few Robust rests in 25 mm but am now re-thinking keeping that dimension and going to 1" in order to fit other aftermarket accessories ... without giving up my Robusts!Your handle will just thread in a little further- about 1/64th”. Which might be one more revolution of the screw, if that much. My original 25mm post tightens solidly down in my modified 1” hole. No problems!

[Brice Rogers]

I never really liked the big 14" wide 25mm tool rest that came with my lathe. So I bored it out by about 0.016 to a full 1.000". That's only about 0.008 on each side. Not much. You have a choice of drilling it, reaming it or abrasively widening it. All work. Your preference depending on what you have to work with.

My lathe has three or four holes in the banjo. I personally think that using two bolts on the 25mm shaft holds it better. At one time I tried putting in an 0.006 or so shim wrapped around the shaft. It works. May not be necessary. But I seldom use the 25 mm tool rest.

[Joe Shanaphy]

Thanks guys! ... Any preferences/tips for widening it at home? My current (new) shop is very limited in tooling ... went from a hugely oversized 2-1/2 car extra deep garage to a tight 1 car standard depth one so a LOT of my tools "went away" ...including virtually all of the metalworking items. I guess I'll be focusing on just turning from now on!

[Roger Chandler]

Thanks guys! ... Any preferences/tips for widening it at home? My current (new) shop is very limited in tooling ... went from a hugely oversized 2-1/2 car extra deep garage to a tight 1 car standard depth one so a LOT of my tools "went away" ...including virtually all of the metalworking items. I guess I'll be focusing on just turning from now on!My preference is to use a 1” twist drill bit, and some cutting oil. Best if you have a drill press, but can be done with a hand drill. Snug it down to the lathe bed, lubricate the bit and hole with a little oil, and have the bit spinning slowly as you enter the cut. Too fast and you could break your wrist. I did my former G0698 with a hand drill, and my current G0766 with my drill press.

[Brice Rogers]

If all you have is a hand drill, then Roger's suggestion would work. If you have a drill press, or have a friend with a drill press, then I'd advise that you use it. Center the 1" bit as well as you can over the hill (rotate it by hand to check) and clamp the banjo. That will eliminate the chance that you get a 3 sided hole. If you use a hand drill, do as Roger said to keep the speed slow but I'd also suggest if your drill has a torque setting that you set it low enough that you don't twist your wrist if it catches.

Keep in mind that when remove such a small amount of material that the twist drill essentially acts as a reamer - - it is doing most of its cutting on the outer edge of the drill - - much like a reamer. And most drill bits are manufactured a few thou undersize (sounds strange but is typically true - - too many words to explain here). So you may end up needing to still sand the hole a few thou. I turned a dowel to around 7/8" and slotted one and turn the other end to 1/2" so that I could chuck it up. Then I slid in a piece of 150 grit sand paper into the slit and ran it up and down until the opening accepted a 1" tool post. I also used a caliper. Didn't want to remove too much.

[Bill Jobe]

If you have a 1" reamer or a core drill I think it would be best to use one of them. A regular drill will try to pull itself through too fast for hand drilling.

[Roger Chandler]

If you have a 1" reamer or a core drill I think it would be best to use one of them. A regular drill will try to pull itself through too fast for hand drilling.Nope, the regular twist drill bit will work fine....I know this from personal experience, but the drill needs to be spinning slowly. That is why its best to use a drill press. Whichever is done the banjo needs to be clamped down securely so it doesn’t move. Very little material being taken off.

[Joe Shanaphy]

My thanks to everyone who added their thoughts to this issue. I actually DID keep my drill press and so will use that. I am assuming that I can use any bit, regardless of what it's made of since it will simply be reaming cast iron.

[Roger Chandler]

My thanks to everyone who added their thoughts to this issue. I actually DID keep my drill press and so will use that. I am assuming that I can use any bit, regardless of what it's made of since it will simply be reaming cast iron.Not a spade bit!!!:eek:A twist bit! I used a silver & deming bit from Dewalt.

[Bill Jobe]

Isn't using a standard drill the reason it grabs when drilling the hole by hand?
I was addressing that issue.

[Roger Chandler]

Isn't using a standard drill the reason it grabs when drilling the hole by hand?
I was addressing that issue.Bill, I was just making the job simple without having to disassemble the banjo and removing the lock down bar. Using a reamer, which is tapered, one would have to plunge the bit all the way through the hole, to get the entire girth of the taper through, necessitating the disassembly of the banjo prior to drilling, and still needs to be clamped securely to the bed if using a hand drill.

Perhaps I am missing something that you are referencing? I’m always open to a better/safer way, so perhaps a pic of the reamer bit you have in mind would be helpful?

[Brice Rogers]

I think that if someone has a 1" reamer, then use it. If you have a Silver and Deming 1" drill bit, then use it. If you have both? Then I'd go for the reamer. If you don't have either then you have the choice between perhaps a $12 S&D drill or a $50 reamer.

Personally, I've wondered how a 1" brake hone would work.... It certainly wouldn't grab, but I wonder how long it would take to remove 0.008" x 2.

[Bill Jobe]

Bill, I was just making the job simple without having to disassemble the banjo and removing the lock down bar. Using a reamer, which is tapered, one would have to plunge the bit all the way through the hole, to get the entire girth of the taper through, necessitating the disassembly of the banjo prior to drilling, and still needs to be clamped securely to the bed if using a hand drill.

Perhaps I am missing something that you are referencing? I’m always open to a better/safer way, so perhaps a pic of the reamer bit you have in mind would be helpful?

My post read "If you have a 1" reamer or core drill".
Neither will grab like a standard drill....particularly when using in a cordless drill.
Sorry for the confusion, Roger.

We used a lot of core drills in the shop. Most machining I did, though, was cast or nodular when a tool like this was require.
Or, maybe I've just been retired too long.:D