Another way to mount a bowl blank.

[Skew ChiDAMN!!]

A while back, when Dingo was having troubles mounting bowls, I was going to post a few pix of various chucking techniques but, for various reasons, didn't get around to it and, I think, others have shown him how to mount a bowl blank since.

However today I had a bit of time to kill so I started playing with an oddment which is an awkward shape to mount normally (either by chuck or faceplate) and perfect for mounting on an odd li'l jigger I have (and have no idea what 'tis called... I call it a "wedgie chuck." :o) I'd just made a start when thought "I should take pix of this so Dingo can see another way of doing it..." (Photos of this "wedgie chuck" are in this post. (http://www.woodworkforums.com/showpost.php?p=364246&postcount=27))

So 'ere ya go, Ding! :)

Pic 1 shows the odd-shaped log I was mounting, as ya can see I've simply drilled a hole in it with a spade-bit to fit the attachment into. 'Tis just under 1" diameter by around 3" deep.

The attachment is simply fitted in, the socket spanner used to tighten it up until it don't tighten no more, (Pic 2) then the whole kit'n'kaboodle mounted on the lathe. (Pic 3) It's turnable from hereon in, however I brought up the tailstock for safety's sake and roughed the outside first. I don't have to mention that it's all well'n'truly out of balance so it should be turned with the lathe on it's slowest speed setting, do I? ;) Or that the lathe will shake, rattle and roll until some blank has been removed?

Because it wouldn't be possible to remount the piece like this later so I could remove a stub and, or turn the foot (not easily, anyway) I decided to turn the foot now, using a mortise instead of a stub so it can be mounted on the chuck in expansion mode. (Pics 4 & 5)

[Skew ChiDAMN!!]

Don't know what I mean by "expansion mode?" Here's how I reverse mounted it. (Pic 1)

The mortise was cut so the chuck fits nicely inside the hole, then "opened up" instead of "tightening in." You follow? The sides of the mortise were tapered slightly to match the angle on my chuck jaws for better locking power. I've actually used my old spigot jaws, which are longer than an ordinary set of jaws as this helps move the base of the blank away from the chuck so there's less chance of skinning knuckles You can see that I also sanded and finished the parts closest to the chuck while it was still mounted on the wedgie....

I like my knuckles just as they are, thankyouverymuch! ;)

I brought the tailstock up with a large conical centre, so it'd sit nicely in the bottom of the wedgie to ensure that the blank was mounted both squarely and to hold the blank tightly in position while I tightened the chuck. Then, with the wedgie & tailstock still in plac4e, I spun up the lathe at it's slowest speed just to make sure 'twas mounted properly.

All went well, stopped the lathe, removed the tailstock and wedgie and started hollowing. (Pic 2) As ya can see, the edges of this piece chipped out, (my own fault... be very, very, very careful when you move the tool-rest in! :o) so I won't be leaving it edged with the original bark as I'd planned. [shrug] 'Tis OK, before making the finishing cuts I'll strip the rest of the bark, wire brush the edges and then char them with a blow-torch.

After final cuts, sanding & finishing I hope no-one'll know the difference. 'Cept you and me... and I ain't telling. ;)

[joe greiner]

Odd-shaped, indeed. Chain saw broken?

JOe

[powderpost]

Not too sure if these methods have been mentioned before, but here goes anyway. Two other simple methods I have used in the past for this situation, are a pin chuck and a male version of the screw cup chuck. The first one is a 50mm length of 25mm diameter steel bar screwed onto the nose thread. The bar had a flat filed on one side, big enough to accomodate a 25mm length of 8# wire or cut 75mm nail, and fitted into a 25mm hole. The other was the male version of a screw cup chuck that actually cut a thread in the wood. I prefered this method as it allowed me to remove the job and rechuck it accurately. It needed a hole about 28mm. Both methods should be supported be a tail stock untill the job behaves itself.
Jim

[Slow6]

patent office?

Skew Chuck?

I'd buy one.

[Gil Jones]

This way is rather simple, but it works well enough. Made a flat on opposing sides of the log with a 38mm Forstner bit, and just turned it between centers until it was in balance enough to mount the tenon in a scroll chuck. It would have been interesting if the log had come off the centers, but it did not.
Thanks for sharing your "Wedgie Chuck", I like it enough to make one.
The Pin Chuck that Jim mentioned is a fine idea too.

[joe greiner]

Gil's technique is hard to beat, but I like the idea of the wedgie chuck too. Here's a thought on a variation based on off-the-shelf components.

Threaded concrete expansion anchor with threads to match the headstock spindle. Definitely available in 1"-8, most likely in 3/4"-10, probably not in finer threads. Also probably not available in "hardware" stores, need to get through contractor supply channels, or such as McMaster-Carr ($$). Most of them have nubs on the expansion sleeve at 180 degrees; align these with cross grain to reduce splitting. Add wood or metal shims to reduce stud cantilever as needed. Tighten nut to secure. Add a coupler nut to join the stud to the spindle. Set this on the top side of the bowl to form bottom with recess or tenon, as taught by Skew. After flipping to cut inside (might still need a cone center on tailstock), remove the insert by chopping up the center stub. If not too yielded, the sleeve can be squished for re-use.

Joe

[Jackson]

Skewie

I like the idea of your chuck but because we're a bit slow up here in the north I don't quite follow. I assume there's a thread mounted beneath the hexagonal part that screws into the hole. Any chance of a photo and some design tips?

Cheers

[TTIT]

Any chance of a photo and some design tips?

Follow the link in Skews first post for a pic of the device - it's from a pushbike head-stem.:)

[Jackson]

I told you we were a bit slow up here! Thanks TTIT

[Cliff Rogers]

I have a Forster bit to suit each of my shark jaws & my long nose pin jaws.
I drill a hole about 20 or 30mm deep in the blank with s suitable sized bit & then slap it on the corresponding set of jaws.

[TTIT]

I have a Forster bit to suit each of my shark jaws & my long nose pin jaws.
I drill a hole about 20 or 30mm deep in the blank with s suitable sized bit & then slap it on the corresponding set of jaws.Ditto.


Worked out why you bother with Mango last night Cliff!!!;) Longest 'noodles' I've ever produced - awesome fun!:D

[Skew ChiDAMN!!]

Odd-shaped, indeed. Chain saw broken?

Sheer laziness, mate, sheer laziness. :D I leave as much meat on the logs as I can while they dry, so that if they crack I'm still left with something usable. Normally I'd rough shape 'em with a chainsaw or bandsaw before mounting, but in this case... [shrug]


patent office?

Skew Chuck?

I can't take credit. This one came with a few other oddments when I bought one of my second-hand lathes. I believe the chuck was made & sold by a bloke in Geelong... I'll have to ask around to find out if that's right and if he's still in business.


I have a Forster bit to suit each of my shark jaws & my long nose pin jaws.

As do I. :) But sometimes the "trough" of the wood is deep enough to hit the chuck body, preventing the pin-jaws from seating deep enough. This little beasty does away with the problem and it also means more tool access to the blank's mounting face, if needed. It also has amazing "rotational grip," I've yet to have a piece spin on the chuck on a dig-in. Stall out the lathe, yes; slip on the chuck, no.