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Large Drive Center

Huh?

What are you trying to do?

Spur drives and scroll chucks are incompatible, AFAICT. I find no scroll chuck specifications listing an internal MT capability, if that's your objective.
 
Sean,
Clay Johnson, choice woods has anew oneway center.
I'm not a big fan of two prong centers but this one looks like it is worth a try.
for $20. I fits all the oneway chucks. so It should fit anything with a center hole larger than the talon.
clay is close to your neighborhood
-al
 

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two prong drive

Keith/Troy
I use a two prong spur drive when I rough out natural edge bowls. I line the two prongs up with the grain. The two prong will bite the wood better than a four prong and you can tip the blank whichever way you need to to get it balanced right.
Dale Larson
 
bestwoodtools has two and four-prong drive centers for the VM120. Two-prong more secure for large bowl blanks.

It's ideal for starting roughout between centers if you use push cuts and chuck for shaping exterior.
 
Just be aware that if the MT slips in the socket you can get galling in it, and the bigger your blank the bigger the risk.

Muscular types who do big lumps on big lathes use a drive dog that screws onto the spindle.

There's a pic of one here that's made here in Australia. There must be US manufacturers. And I think I've seen two spur versions.
 
The Stubby spur drive works very well...

When roughing smaller blanks (10-12" or smaller), I usually begin by roughing the shape and forming the tenon between centers using a 1-1/4" diameter Steb Drive, chucked into my Vicmarc VM100 chuck. On larger blanks, I use the Stubby Drive Center, (the 1-1/4"-8tpi version) on which I have removed two of the spurs (resulting in a two-spur drive). This is sturdy, easily removed, and works very well. I much rather have a drive center that screws onto the spindle rather than one that uses a Morse taper.

I have toyed with the idea of trying the new "plate" center from Oneway, but decided that I don't really need it. A question raised at our last turner's meeting was whether this new spur drive will center properly, and if it will work with chucks other than Oneway's. Has anyone tried one of these on Vicmarc or on Nova chucks?

Turn safely,

Rob Wallace
 
I just called Vermec, in Australia, and ordered the ACC-200 50mm Drive Dog. All steel construction with a spindle adapter included. Been looking for a large, steel drive center that will screw onto the spindle for a while (thanks again, Ern). $100.63, which includes $27.22 Air Mail shipping, from OZ to GA.
http://www.vermec.com
Gil
 
Hope it works well for you Gil.

I had one for the Stubby. Particularly useful for large natural edge blanks - holds through the bark and allows you to reposition the tailstock end once you've done some outside roughing, so you can see whether your high points are going to line up.
 
Ern,
I reckon it will do quite well from the beefy look of it.
And I like the spindle adapter part of it too, if I ever change lathes.
Not excited about the week+ shipping time, but Georgia to Brisbane is a bit far to drive to.
Gil
 
rsser said:
Just be aware that if the MT slips in the socket you can get galling in it, and the bigger your blank the bigger the risk.

Muscular types who do big lumps on big lathes use a drive dog that screws onto the spindle.

There's a pic of one here that's made here in Australia. There must be US manufacturers. And I think I've seen two spur versions.
Click to expand...

If the MT slips, it might mean that everything was not properly cleaned before inserting the MT drive center into the socket, excessive vibration has rattled things loose, or that it already has been damaged and, as a result, doesn't provide adequate metal to metal molecular bonding to prevent slipping.

However, your point is well taken since most woodturners don't understand all the fine points about machinery. I have even heard demonstrators say that the drive center slipping in the socket is a safety feature. It's enough to make me want to pull out my hair ... if I still had any.
 
Exactly right. Why anyone would think an MT would hold without adequate pressure against it is beyond me, much less cleaning the thing. If you want a spur-type drive center, it really needs to be a thread-on. I've one of Bill Rubinstein's (http://stubbylatheusa.com/Convertible_Drive_Center.100.pdf) for my Stubby and he's now making them in both 1 1/4 x 8 and M33 x 3.5 sizes. The blades and point are removable for sharpening or going two or four point.
 
Bill Boehme said:
If the MT slips, it might mean that everything was not properly cleaned before inserting the MT drive center into the socket, excessive vibration has rattled things loose, or that it already has been damaged and, as a result, doesn't provide adequate metal to metal molecular bonding to prevent slipping.

However, your point is well taken since most woodturners don't understand all the fine points about machinery. I have even heard demonstrators say that the drive center slipping in the socket is a safety feature. It's enough to make me want to pull out my hair ... if I still had any.
Click to expand...

I agree about proper cleaning, but I'm skeptical about molecular bonding - manufacturing tolerances for the shank and socket just don't seem tight enough for that. Machinery's Handbook indicates frictional resistance as the holding mechanism, and surface elastic deformations in both elements could accommodate very slight mis-fits.

I have a Black & Decker hammer drill, circa early 1940s, patented by Alonzo Decker Jr., that uses MT for the drill bits - a hammer drill, of all things! It uses a wedge in slot for bit removal, instead of a knockout bar, and it still requires a lot of persuasion and foul language.

If it's loose enough to slip, it wasn't very safe in the first place.
 
Joe Greiner said:
I agree about proper cleaning, but I'm skeptical about molecular bonding - manufacturing tolerances for the shank and socket just don't seem tight enough for that. Machinery's Handbook indicates frictional resistance as the holding mechanism, and surface elastic deformations in both elements could accommodate very slight mis-fits.

I have a Black & Decker hammer drill, circa early 1940s, patented by Alonzo Decker Jr., that uses MT for the drill bits - a hammer drill, of all things! It uses a wedge in slot for bit removal, instead of a knockout bar, and it still requires a lot of persuasion and foul language.

If it's loose enough to slip, it wasn't very safe in the first place.
Click to expand...

Mornin' Joe.....

I'm not sure what "molecular bonding" is......what does that mean? To my way of thinking, a perfect fit is what's needed for good grip in the MT. If the mating surfaces are clean, and you get slip......then the only thing that can be concluded is the fit isn't right........

My Delta drill press uses the same MT and slot for removal of the chuck. I can sympathize about removal. A couple years ago, I used a large drill bit made for MT. I thought it would be an easy thing to remove the chuck, but it didn't turn out that way! :mad: I would assume if bits were constantly being removed and installed, it would have been easier.......!

ooc
 
Mark Warden said:
This is what you need for the slotted MT. http://www.highlandwoodworking.com/browseproducts/-1MT----2MT-Drift-Pin.HTML
Click to expand...

Hey Mark......

Yep, got one of those......didn't work very well for my chuck that stayed in place for about twenty years before I tried to remove it! Like I said, I believe the system works much better when it's used with some frequency.

We have had many freezing winters and hot summers.......so, I suspect that a little corrosion may have been a piece of the puzzle.....although, I don't recall it being in strong evidence.....

ooc
 
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Rob Wallace said:
I have toyed with the idea of trying the new "plate" center from Oneway, but decided that I don't really need it. A question raised at our last turner's meeting was whether this new spur drive will center properly, and if it will work with chucks other than Oneway's. Has anyone tried one of these on Vicmarc or on Nova chucks?
Click to expand...

Rob,

I just received the Oneway Big Bite plate center from Choice Woods, and the packaging says that it works on chucks with a 1-inch center hole. I just checked to make sure it would fit in my Nova G3 chuck, and it fits very nicely with no discernible play, so I suspect it should center quite well once I actually get a piece of wood on the lathe (I can't turn tonight). The tab at the back fits into the center hole of the chuck. By the way, this is one big center, measuring nearly 3-1/2 inches across. I hope to get a chance to play with it this weekend.

John
 
Mark Warden said:
My Dad had a steel fabrication shop i have seen 2 used from opposite sides with a C clamp.
Click to expand...

Good idea, Mark......nothing like a little creative thinking!

ooc
 
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