What is a Self-locking Stub Arbor?

[Chips O'Toole]

I found out a guy named Duclos made his own air spindle and wrote it up in Home Shop Machinist magazine, so I bought a back issue and looked at it. It looks like a surprisingly simple project, which suggests there are things about it I don't understand. The article appears in two issues, and I don't have the second part yet. Maybe that's where the fun starts.

As part of the process, he tells the reader to make a self-locking stub arbor. He gives no details at all, like every hobbyist is born knowing how to do this. I don't even know what a self-locking stub arbor is. I know what an arbor is, and I guess "stub" means it's short, but that's about it.

Can someone tell me what he's talking about? I'll upload a photo of a photo. Sorry about the quality.

 

[mmcmdl]

Not sure how it relates to the air spindle , but there are many types of locking arbors . Think of how a Hardinge lathe chuck adapts to the spindle . Most only lock in one direction so be aware of CW or CCW rotation .

 

[Chips O'Toole]

Unfortunately, I do not know how a Hardinge chuck works.

 

[JimDawson]

Never seen or heard of that before, but it looks like a sprag clutch. I normally make stub arbors that are either threaded OD or ID as needed to secure the part. These are normally built as a temporary, single use, work holding device.

 

[mmcmdl]

OK , how about counterbore sets . It has one arbor and all of the different size c bores lock at 1/4 turn . Usually a pin with an angled cam which locks them on . Removed easily with channel locks , pliers etc .

 

[jmkasunich]

I found out a guy named Duclos made his own air spindle and wrote it up in Home Shop Machinist magazine, so I bought a back issue and looked at it. It looks like a surprisingly simple project, which suggests there are things about it I don't understand. The article appears in two issues, and I don't have the second part yet. Maybe that's where the fun starts.

As part of the process, he tells the reader to make a self-locking stub arbor. He gives no details at all, like every hobbyist is born knowing how to do this. I don't even know what a self-locking stub arbor is. I know what an arbor is, and I guess "stub" means it's short, but that's about it.

Can someone tell me what he's talking about? I'll upload a photo of a photo. Sorry about the quality.

View attachment 312116

From the photo, I'm guessing that then the cutter (not shown) tries to rotate on the arbor, that little pin rolls with it until it wedges between the ID of the cutter and the flat on the shaft.

 

[Cadillac]

From the photo, I'm guessing that then the cutter (not shown) tries to rotate on the arbor, that little pin rolls with it until it wedges between the ID of the cutter and the flat on the shaft.

That would do absolutely nothing. Assuming the cutter has a round hole for mounting to the arbor with the above situation the cutter would still spin. If the cutter had a keyway and the pin fit the keyway the cutter would have some movement until it rolled to the edges of the flat on that arbor. Guess will have to wait for vol.2 of the author to find out.

 

[mmcmdl]

Fun At Home Shop Projects ........commenly Known As " G " Or Government Jobs

Cheap mans boring head . Not a Criterion nor Walhopter but will get you thru non-critical jobs . Bore or drill a piece of stock in one end true to OD . Turn part around and turn an OD that is offset for your shank . Make another piece that fits your bore with an offset boring bar hole . You...

www.hobby-machinist.com

The boring head uses a cam type self locking mechanism .

 

[Chips O'Toole]

The arbor is for stock, not a cutter.

 

[Chips O'Toole]

It looks like no one here knows what "stub arbor" means in the context of the article, which confirms my suspicion that the reference was not adequately explained. The author of the article tossed it in there as if any machinist would know what he meant, but it appears that he was expecting a little too much.

Now I have to ask myself...do I care enough about this to venture over to Practical Machinist and deal with the flame masters?