Looking for a 1inchx8tpi to 1-1/2x8tpi spindle adapter

Dave Kartzman · Dec 26, 2009

I'm very new to woodturning, so I apologize for this question in advance.

I found a Glaser Screw Chuck online for purchase but it is a 1 1/2inch screw diameter(fits conover lathe). I have looked for a 1 inch to 1 1/2 inch headstock spindle adapter but can seem to find everything but. Is there anyone out there that may know where I can get an adapter with those dimensions (also 8tpi)? I looked at the PSI international but they don't have an adapter that size.

Thanks in advance....Dave

Grant Wilkinson · Dec 26, 2009

Try here

http://bestwoodtools.com/

Look under Woodturning tools and accessories, then under precision steel spindle adaptors.

loberg · Jan 1, 2010

Woodcrafter 146798. $5.99. Screws to the inside of the chuck and over your spindle.

Kevin Kelly · Jan 29, 2010

Be careful about the adapter. I think it's a Powermatic that also has 1-1/2x8 spindle, but its threads are different than a Conover's. So for instance, a screw chuck threaded for a Conover would work on the Powermatic, but the Powermatic chuck would not fit the Conover.

Joe Greiner · Jan 30, 2010

Kevin Kelly said:
Be careful about the adapter. I think it's a Powermatic that also has 1-1/2x8 spindle, but its threads are different than a Conover's. So for instance, a screw chuck threaded for a Conover would work on the Powermatic, but the Powermatic chuck would not fit the Conover.

Can you elaborate on this?

Thread form itself? Class of fit? Quality of machining? Length of thread to shoulder? Some other factor?

Kevin Kelly · Jan 30, 2010

Joe, If i remember correctly, it has something to do with the thread form itself. I want to say that it's the thread spacing - maybe one is slightly wider than the other. With the scarcity of Conover lathes, i can't put my hands on where i read about this, but if you look at Oneway's website, where they list the taper-lock adaptors, you'll see the make two different ones in that size - one for Powermatic, one for Conover. The only reason i know this is that i have a Conover, and i did a lot of research on it a few years ago. I'm certain i read that the Conover accessories will work on the Powermatic but not the other way around. It's one of two things i don't like about my lathe - thread size and Morse taper size (Conover has a #3 in the spindle, fortunately a #2 in the tailstock). Sorry i can't provide any more detail than that.

Joe Greiner · Jan 31, 2010

I'd never heard of the Conover until now. But Google came to the rescue. It looks like a very nice setup.

I'd have to guess that Conover is the odd man out. There are about half a dozen variables in thread forms in addition to diameter and TPI, generally related to shape at the tip. Add 55-degree Whitworth and Acme, and it's a zoo.

Regarding your complaint about the MT3 spindle socket, CSUSA and Grizzly both have adapter sleeves to receive a MT2 tool. They're not open at the spindle end, so you'd also need a drift wedge to remove the MT2 when/if.

Kevin Kelly · Jan 31, 2010

Thanks, Joe. I actually have a couple of the adaptor sleeves. They're handy. And yeah, i think you're right. The Conover is the odd man out. Still really like, though.

Kevin Kelly · Feb 6, 2010

For Joe or anybody else who might be interested, this is from the horse's mouth, Ernie Conover:

A Conover Spindle is copied from a South Bend 9" Lathe. It is a 1-1/2" DIA Spindle with 8 Threads Per Inch. The Spindle is 7/8" long to the shoulder, but only 11/16" is threaded. The remaining 3/16" is a centering band that is proud of the thread. The DIA is 1.509". All accessories have to be counterbored to 1.510" DIA for a little greater than 3/16". 7/32" is a good working figure and you can go 1/4" with no problem. This scheme ensures perfect centering of faceplates, chucks and such every time even though the thread is only a class III.

Joe Greiner · Feb 7, 2010

Excellent research effort, Kevin. You could be a news-hound or detective in your day job.

I did a little more digging, and I can't help repeating my praise for that lathe. Substantially adjustable swing and length with some DIY modifications, although moving the banjo and tailstock could be slightly improved. Sad to say, it wouldn't fit in my sliding-block puzzle of a shop. One owner wrote "Turning on this lathe is like driving a Cadillac."