2 inch 2MT 4 prong drive

I think that you should think about replacing it with a large drive center which screws on to your spindle rather than being driven by the taper. We all are really misusing that taper by using it to drive large loads. There are several suppliers who sell these things -- maybe somebody else can come up with the names because the one I own is no longer on the market. If you can't find one in UK, I'm sure one of the US companies would ship and with the relative weakness of the USD, you might not come out too badly.

Bill

Gregory Moret> I have for a year or so been using a 2 inch 2MT 4 prong drive to hold

Time to consider a pin chuck. They have them here, as well as screw-on "Texas-Size" 2 and 4 fanged spur centers.

Check the pocket in my wife's pants. She lost her car key two weeks ago--thought she had thrown them out along with empty bags from the grocery store. Yesterday I came within a hair's breadth of buying her a new one (not just a simple key: it's electronic with a remote opener and alarm switch). I didn't because the line was too long at the dealer, and after I came home she announced she had found the key in the pocket of her pants, which she apparently hadn't worn since that day (or laundered, I pointed out to her). Who knows...

"George" wrote in news:42f20767 snipped-for-privacy@newspeer2.tds.net:

George,

I only looked for a couple of minutes, but where are the pin chucks on that site? I found the big spur centers...

You keep recommending these, and I keep not finding them. ;-)

Patriarch

Those you have to call for. They just started making them recently. Know a couple of guys who have 'em, including me, and they're good items. It's a mom-and-pop outfit, and they get a bit more involved in the work than the documentation sometimes.

Greg

Have you tried Planet. I think they are based in Newtown, Wales. I seem to recall they had a large drive in their catalogue

Mark Hancock

LRod

Oh for a universal English Languange.

Nothing Personal but I had to re read your post a couple of times to get things straight in my mind. In England pants are obviously not what they are in the US :-0

Greg

George

I really like the look of the Texas spur drives on the Bestwood site. Unfortunately they as you say are the screw in type and for my purposes I need a MT drive.

Let me explain....The pieces I am making are from Monkey Puzzle (Araucaria auracana), which is similar to Norfolk Island Pine (Araucaria heterophylla), though the monkey is a broad leaved conifer and the Norfolk a needle leaved one. Botany lesson aside the lumps I'm putting on the lathe are about 16 inches long and 20 inches or more in diameter. To say they are heavy is an understatement with some weighing in at as much as a 100 lbs.

Now what I try to do, in order to get the finished form I am after, is balance up the natural edge once the wood is on the lathe. Because of the size and the whorl of knots it takes a bit of maneuvering to get it right. I could not do this before mounting as I need to revolve the piece 360 degrees after each adjustment to see if it is right. I use the tool rest as a reference point as to where the edge will be. Too see what I am aiming at there is a picture of a good one of my bowls on our clubs web site

Back to the problem with screw in drives. This wood is relatively soft on the end grain and the centre needs to be well seated to get a good driving hold. I can't mark where the drive will be before I mount the piece and to take the piece off to mark it then put it back is trickier than it sounds. So what I do once every thing is positioned exactly as I want it is to knock the drive through the hollow of the tail stock in to the wood. The alignment will obviously be perfect as the force is exactly in the centre. (A hammer blow before the piece is mounted can some times leave the indent for one or more of the prongs deeper on one side than the other, thus giving a slightly looser grip.) There is no stress on the head stock as the taper allows the drive to move freely in that direction and there is no excess force on the tail stock due to a foot or more of wooden shock absorber. Once seated a few turns on the tailstock hand wheel will bring the Morse taper up tight again.

Another advantage of an MT is that with such a heavy bit of timber in the equation it is far better to have a few points of slippage. At a one to three ratio with a 1 inch bowl gouge a bit of slip is far better than a shredded mounting point which will never quite line up again.

Greg

George

I really like the look of the Texas spur drives on the Bestwood site. Unfortunately they as you say are the screw in type and for my purposes I need a MT drive.

Let me explain....The pieces I am making are from Monkey Puzzle (Araucaria auracana), which is similar to Norfolk Island Pine (Araucaria heterophylla), though the monkey is a broad leaved conifer and the Norfolk a needle leaved one. Botany lesson aside the lumps I'm putting on the lathe are about 16 inches long and 20 inches or more in diameter. To say they are heavy is an understatement with some weighing in at as much as a 100 lbs.

Now what I try to do, in order to get the finished form I am after, is balance up the natural edge once the wood is on the lathe. Because of the size and the whorl of knots it takes a bit of maneuvering to get it right. I could not do this before mounting as I need to revolve the piece 360 degrees after each adjustment to see if it is right. I use the tool rest as a reference point as to where the edge will be. Too see what I am aiming at there is a picture of a good one of my bowls on our clubs web site

Back to the problem with screw in drives. This wood is relatively soft on the end grain and the centre needs to be well seated to get a good driving hold. I can't mark where the drive will be before I mount the piece and to take the piece off to mark it then put it back is trickier than it sounds. So what I do once every thing is positioned exactly as I want it is to knock the drive through the hollow of the tail stock in to the wood. The alignment will obviously be perfect as the force is exactly in the centre. (A hammer blow before the piece is mounted can some times leave the indent for one or more of the prongs deeper on one side than the other, thus giving a slightly looser grip.) There is no stress on the head stock as the taper allows the drive to move freely in that direction and there is no excess force on the tail stock due to a foot or more of wooden shock absorber. Once seated a few turns on the tailstock hand wheel will bring the Morse taper up tight again.

Another advantage of an MT is that with such a heavy bit of timber in the equation it is far better to have a few points of slippage. At a one to three ratio with a 1 inch bowl gouge a bit of slip is far better than a shredded mounting point which will never quite line up again.

Greg

Maybe, but I'll bet they don't have pockets...

Robert Sorbey - STEB Center 1/2" x #2MT at Woodcraft, catalog number 145519

Matt

Thanks but unfortunately it is only 1 1/2 inches not the 2 that I would like. Axminster used to do a 2 inch one but found the market too small and they no longer do one offs in the way they used to either.

Greg

They will make you one, of course, being a mom-and-pop machining outfit. Distance is your enemy. Or, you could do a double-shuffle and get the fangs and one of their MT-to-Thread adapters. Some folks use them to mount in the tailstock for reverse centering.

I just find geographic center or clearance on odd-shaped pieces and bore a hole before mounting, using a bit of chisel or drill bit to remove weight in areas where I will be removing stock anyway to balance up.

"Gregory Moreton" wrote: (clip) So what I do once every thing is positioned exactly as I want it is to knock the drive through the hollow of the tail stock in to the wood. (clip) ^^^^^^^^^^^^^^^ I guess everyone is so intent on helping you find the Morse taper spur drive, that no one noticed this unusual and very clever idea. Let me be the first to compliment you on a neat technique, and direct everyone else's attention to it.

Hi Leo

Yes I did notice the way Gregory said he was seating his spur center, however the thought of regularly driving a spur into the wood that way I didn't think was such a good idea, flaring the morse taper and damaging the head stock spindle's inner taper, also a good chance of dirt falling in between the spur drive taper and spindle when the spur drive is driven out of the spindle and into the wood, however he seems to have done this for a while and maybe I'm just "seeing" things, however I think a center pin in combination with a small face plate that has some sharpened bolts or pins in it, (would drive the wood like a dog on a metal lathe), would probably do as well or better than a spur drive. Anyway I could not help him with his 2" Morse taper and I'm not about to tell Gregory that the way he is doing things is not the way to do it, after all as they say there is more than one way to ..... a Cat.

Just the way I see things, and yes sometimes I need glasses to.

Have fun and take care Leo Van Der Loo

Leo Lichtman wrote:

"Leo Van Der Loo" wrote: (clip) the thought of regularly driving a spur into the wood that way I didn't think was such a good idea, flaring the morse taper and damaging the head stock spindle's inner taper, (clip) ^^^^^^^^^^^^^^^^ Yes, Leo the Other, I think your concern is valid, but let me tell you why I think he hasn't had a problem. He is using a knockout bar to deliver the impact. From years working as a mechanical technician, I learned that a long slender drift punch cannot deliver a really hard blow (as when knocking out a taper pin.) What happens is that the drift punch, or knockout bar tends to spring sideways, limiting the intensity of the impact.

My main concern, when I read Bill's description was that he might have a hard time hitting it hard enough to really seat the drive in the wood. Evidently the combination he is using goes right down the middle, between both our "pitfalls."

Leo and Leo

Sorry to take my time replying to your posts but I have been at the AWGB seminar at Loughbourgh this weekend. (The UK equivilent to the AAW symposium but not quite as big.) In fact I had one of my peices in the instant gallery selected in the top 50 so I am quite chuffed.

Most good MT drives have a wasted area at the end of the taper, which is where my bar impacts. The bar I use is rounded at its end. These two factors coupled with the fact that the bar is the right size to fit within the hollow mean there is very little burring over on the MT. If it does seem to be burred it is an easy job to grind it back as this will invariable occure in the wasted section at the end and not contact the taper of the spindle.

I don't use a hammer so the force is minimal and I have never needed to grind the end of the taper back. I do this very regularly and have been doing so for years so I reacon from that point of view it is fairly safe. In my opinion and from my experience this practice has caused no noticeable damage to either the spindle or MT or my drives.

I asked around at the seminar and I am not the only turner doing this but it seems to be an idea that not many have picked up on. All I can say is that on large peices of wet end grain held between centres it makes a real difference. Give it a try.

Gregory