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Col Mckee
05-02-2006, 09:08 PM
I need to turn about 2 or 3 thou off the OD of an off the shelf bronze bushing with a 3/4" bore. Seems like an adjustable lathe mandrel would do the job, but I'm having trouble finding anything but a 'no-name' import. Now I don't want to spend 40 or 50 bucks on a cheap import that won't get the job done, but neither do I want to postpone the project for a long (unknown) while waiting to trip on one. Anyone know of a source for a quality adjustable mandrel? Thanks...John

jimmstruk
05-02-2006, 09:26 PM
Col Mc,,Check enco sale flyer or online for a whole set of expanding mandrels. Look to be agood buy IMO JIM

topct
05-02-2006, 09:39 PM
For those I make a simple spigot.

Chuck a piece of cold roll in the three jaw. Turn to fit inside diameter.

A small tapped hole in the end with a screw and washer to hold the bushing on, turn to size.

Yes I turn the washer down along with it.

jimmstruk
05-02-2006, 09:49 PM
Col My mistake, the mandrels I was thinking of must have been in an older sale flyer. Just found them! Catalog#dt262-5110 8pieces 1/4thru1 1/4 for$29.95 price good thru 5/31/06 JIM

JRouche
05-02-2006, 10:19 PM
Jimm has the right idea, enco has good prices and decent quality. I prefer the mandrels to the arbors. The mandrel can be used with, and should be used with a center rest. JRouche

Really though. Mandrels should be a do it yer self project for the lathe, this is HSM....

http://www.use-enco.com/CGI/INLMK3?PMK0NO=716956

cruzinonline
05-02-2006, 10:32 PM
For something that size just make a simple mandrel. Rough machine it to size the split it down the center axis with a band saw or porta band or heck, use a hack saw for this size. Chuck it back up, drill and tap, oh about 3/8-16 and then countersink the heck out of it. Turn to final size less about .002 then use a flat head screw to expand it. In time you will have a complete set so make it nice.Make sure you leave a shoulder on the back side so that you will have something nice to indicate in next time unless you are putting in a collet.

Forrest Addy
05-02-2006, 10:49 PM
Expanidng mandrels are always tempting and simple looking. Their use seems intuitive but they also have their limitations. Fact is they don't hold well: meaning they slip, and their grip diameter turns hour glass shaped if not used at the diameter they were designed for.

Mount your bushing on a spud as topct and others suggest. It's the work of 20 minutes and far cheaper, more trouble free, and accurate than the purchase of an expanding mandrel making the purchase seem an unjustified expense.

wierdscience
05-02-2006, 11:12 PM
If it's a sintered bronze bearing use a spiggot or a mandrel.If it's a machined cast bronze bearing chuck up a piece of scrap round bar large enough so you can turn up a quick 40-50* taper ,use it along with a live center to hold the bushing between centers.2-3 thou doesn't take much torque and it will be just as concentric as if you had used a spiggot or mandrel.

big-dipper
05-03-2006, 05:13 AM
For something that size just make a simple mandrel. Rough machine it to size the split it down the center axis with a band saw or porta band or heck, use a hack saw for this size. Chuck it back up, drill and tap, oh about 3/8-16 and then countersink the heck out of it. Turn to final size less about .002 then use a flat head screw to expand it. In time you will have a complete set so make it nice.Make sure you leave a shoulder on the back side so that you will have something nice to indicate in next time unless you are putting in a collet.

Or tap for tapered pipe plug.