homemade cole jaws

[Daddy3x]

So I finally got some longer m4 screws and broke down and bought some "buttons" from the company. I made 12" dia disk from scrap from 5/8" mdf. I finish tested and turned the bottoms on three bowls that had been sitting waiting for me take a "sick" day. Well, the first two went well, the thirrd one was a charm, it really exploded off, 3 of the 4 wings snapped off, but hey, i was able to save the bowl ! it will now be more of a contempporary peice, with some hand carved details and a whole lot of sanding

any suggestions on a new material to make my next set? Slow lathe down using same material? I am just too cheap to buy that aluminum set.

[DavidG]

[Sawdust Maker]

[robutacion]

Hi Daddy3x,

Yeah, you and another thousand of us went through the same. A simple search on our library will give more ideas than you can poke a stick on...!, seriously!.

Good luck

PS: Are you good and quick at "ducking"?

Cheers
RBTCO

[Mulgabill]

G'day Daddy3x
As with all types of Cole jaw chucks, it should be used at slow speed. The centrifugal force of such a type of chuck is greater when "loaded" with a bowl.

[joe greiner]

Material might not be the culprit. More likely inadequate edge distance to the holes, or between holes. If your MDF pattern is cloned from a stronger material, bad news.

Cheers,
Joe

[Mobil Man]

Go with 1/2 or 3/4 inch plywood. You'll never blow it apart.

[Daddy3x]

Thanks everyone. I did take some pics, however I need to consult my nine year old on how to reduce it to 800 x 600 pixel size for uploading, it is at 3024 x ? right now and I don't have time to research that up right now. I am good at ducking, and even better at being certain I am listening to what is happening, it gave me my first clue that something was about to hit the fan (literally too). I used common sense and stayed out of the line of fire, had on a faceshield, but had no shirt on at the time (just tinkering for a minute while waiting for the clothes to get out of the drier). Usually I wear a leather apron. Thanks again, I will be working of pic issues.

[QC Inspector]

Thanks everyone. I did take some pics, however I need to consult my nine year old on how to reduce it to 800 x 600 pixel size for uploading, it is at 3024 x ? right now and I don't have time to research that up right now.

You could just re-shoot the pictures at the lowest resolution setting on you camera. I suppose you'll need to ask your 7 year old daughter how to reset the camera though.

[Daddy3x]

The easiest directions I have ever been given, thanks I wish some of my colleagues would give such brief answers. I only know what I need to know about computers, will try to post pics later.

[Daddy3x]

Here the mess is. My daughter just told me to get the directions out, I hate doing that.

[Alastair]

Haven't tried it myself yet, but have heard of HDPE or nylon sheet, (eg cutting board) being used successfullly for this.

regards

[powderpost]

Made a set some time back. Went to the local machine shop and bought a square of aluminium and cut it round on the bandsaw. I have a nonferrous metal cutting blade in the saw. The buttons are made from a nylon cutting board bought from a Salvo's Store. I have used it many times without failures. Lots of hole boring and thread cutting, but it was worth it.
Jim

[Skew ChiDAMN!!]

MDF!?!?

PLY!

Or perspex or ally or... almost anything 'cept MDF or chipboard or particleboard! [shudder]

Don't forget that there's not only centripetal/inertial forces at play (there's no such bogeyman as "centrifugal force" ) but there's also lateral forces pushing the jaws towards towards the headstock. eg. any tailstock pressure on the bowl or any lateral pressure you're applying to the tool, etc.

And with cole jaws being as "long" as they are, that's a lot of leverage. It doesn't take much to snap a 1" wide strip of MDF and the jaws aren't that much wider at the chuck end...

[QC Inspector]

The easiest directions I have ever been given, thanks I wish some of my colleagues would give such brief answers. I only know what I need to know about computers, will try to post pics later.

Glad to help and surprised to see that someone actually followed my advice.

Can't add too much to what the others have said about materials except. Don't use Plexiglas / perspex! It is brittle and may break like the MDF did. If you want your bowl to appear to be spinning in midair to the amazement of onlookers, then use a polycarbonate like Lexan. It's what they use in safety glasses and face shields because it is tough and flexible.