Method of rapidly centering regular shaped stock for turning

Somehow I got lost there. Do you have a picture?

"Gerald Ross" wrote: Somehow I got lost there. Do you have a picture? ^^^^^^^^^^^^^^^^^^^^ I got everything except how you center the work.

Sounds to me like he's talking about a dowel center:

...or something similar. Drop one into the center hole in the chuck, then let the chuck jaws center the workpiece over the point. Tap on the opposite end of the workpiece to mark the center. Reverse the workpiece and repeat. B.

Buddy, you've got it. (Saves my having to work out how to send a picture for Gerald) The 'dowel centre' that I made on my metal-working lathe is the same design as the dowel centres shown in your link, but the body is threaded (1/2" BSP) to fit into the chuck mounting hole. The sharp nipple is conically shaped, about 1/8" across at its base. By giving the workpiece a good tap the conical dent made in the workpiece is quite sufficient to easily mount the workpiece between the forked centre in the head stock and the tail stock centre. If you don't have access to a metal lathe then a bung/plug turned out of hardwood with a masonary nail in the centre would do. Make the plug long enough to rest on the work bench (i.e. flush with the chuck backplate) so it doesn't get knocked through when you hit the workpiece. To prevent your workpiece pulling the plug out, put a small shoulder on the bottom of the plug (as opposed to the top as is the case with the dowel centres mentioned) and insert it via the back of the chuck. (That's why I threaded my plug). As I mentioned, I'm not up to speed on posting pictures but I would be happy to email one should it still be thought useful.

Thanks for your interest in my post.

Exbrat

Hi Exbrat, Thanks for offering your method of centering regular shaped stock. I hope your post will stimulate us to post (and repost because we often get in a technique rut, plus we forget previous suggestions and seldom use the archives) our ideas and try other's variations on common turning methods. Rote is good, but thinking is better. :)

I thought to try your method to make the tail dimple in small slightly irregular square stock for centering in a scroll chuck (I'm making lots of Darrell's icicles). I haven't tried it, but from my armchair I'd think your method wouldn't work for spindles smaller than the hole in the chuck body because there would be nothing to set the dowel pin against. right/wrong?

Thanks again for posting your suggestion. Keep em coming!

Turn to Safety, Arch Fortiter

Sorry Exbrat, I forgot about turning an adapter to fit inside the hole to fix and center the pin. I have a metal lathe and plan to try making one.

Turn to Safety, Arch Fortiter

hth Exbrat

Or, they could just buy one of these.. lol

mac

Please remove splinters before emailing

Mac, if you know of a supplier/manufacturer who stocks/makes such chuck accessories covering the most common headstock spindle threads please share your source. I personally haven't seen such an accessory on the market. Of course one can get one's local machinist to knock the accessory up at a price. All I was offering was the idea.

Exbrat

As I understood it, you wanted something to fit in your chuck, have a point and tap stock to mark it, right? I still like the link I gave you for a wall mounted one, but how about this:

I have one ordered, but just because I'm tired of taking the chuck off the spindle just to do a few minutes of work between centers... mac

Please remove splinters before emailing

Regardiong the center in this link, it looks to me like it must be held by the closed jaws, so it would mark the work, but not center it. Am I seeing it right?

this:

> I have one ordered, but just because I'm tired of taking the chuck off the > spindle just to do a few minutes of work between centers... > > mac

No mac. A misunderstanding. I wanted something that centers the workpieces quickly and accurately over a sharp spiggot, poised to be hammered down onto it. The workpiece can be any dimension that the four jaw chuck can take. The chuck does not need to be mounted on the lathe. It is best lying it on its back on the work bench. The technique shown in your link is one I have used for many years using countersink bits for small workpieces and homemade parallel shaft forked center for large workpieces.

Exbrat

A pic to ABPW would REALLY be helpful. I'm a newby but I'm having trouble visualizing what you did here. Thanks for the contribution.

Looks like a modification of the Robert Sorby steb centre.

Hi Tom, No it's not like the Robert Sorby steb centre. That, as I see it, is just another drive center with a parallel shaft that can be fitted into a chuck as opposed to a morse taper shanked drive center fitting into the headstock direct. It has its uses of course as it obviates the need for swapping out the chuck all the time. As I mentioned in my post to Mac, I use a countersink bit for small workpieces and a home made (modified old Forstner bit) for larger work. So, back to my idea. It is not another drive center! It's a way of accurately and rapidly marking and indenting regular sectioned workpieces ready for mounting between centers.

Hi Patrick and Gerald Ross, We must have reached a thousand words so I think a picture(s) is right. I'll do that. Just have to buff up on how. The pointer to ABPW has put me on the right path. Watch that space. May take me a few hours.

Exbrat

Yep.. from Lee Valley, of course..

Ok for spindle work, but sort of useless for bowls, IMO.. >

yep.. I probably misunderstood the OP.. Sounded like he wanted a pointy thing in his chuck, with the chuck lying flat on a bench, so he could mark center??

I've been using the same $3 plastic center finder for years, with a spring punch..

mac

Please remove splinters before emailing

IMO, it's just a way to have a drive center mount where my chuck screw goes, so I can leave the chuck in the spindle.. just lazy.. ;-]

mac

Please remove splinters before emailing

Hi again Patrick and Gerald

I have uploaded some pictures onto group

It seemed to be the easiest to get to. My first attempt to upload pics to a Google Group. Hope it worked. Exbrat

Mac, Here's a link to some pics I've just uploaded

Hope that gives you a better idea of what I was posting about. I too have been using a plastic center marking tool for years. I hope you'll agree that I've improved on that a little. Cost me nothing, not even $3.00.

Exbrat