Crawford Collets ? – huge manufacturer of collets.

Norman

Edited By NJH on 03/06/2016 17:25:11

They don't look like the Burnerd multisize collets I've got, however they are from Crawford Collet. Of course I can't load the apposite PDF so here's a link to a relevant page:

**LINK**

And click on the line that says 'Plain Bore Multibore Collets'.

Andrew

Edit: I don't think any bits are missing!

Edited By Andrew Johnston on 03/06/2016 17:43:46

Useful photo on this page

**LINK**

I'm still not certain, but it looks like there are rubber inserts in the side holes.

MichaelG.

Looks like it is meant to have rubber inserts in the holes, but I can't tell if they are there or not.

Neil

It is a Crawford multisize collet. it is complete as is since these didn't have the "leaves" that Bernard (and others) used.

If the correct collet chuck is with it then no problem it can be used, that particular one will hold between 1/4 and 3/8 as indicated. From the photo it is difficult to say which series of collets it is from since there were five different series, B going through to F the largest went up to 3 1/8 inches but the B series stopped at 1 1/8. All were available in light duty with plain bores (as sample) or heavy duty with serrated bores. They are not interchangeable with Bernard collets since they have a different included angle on the body and various other dimensional differences.

They do turn up occasionally on a certain auction site in round, hexagonal and square bores and I own a full set of all the "B" range however I seldom use them because I find the Bernard type to be superior for my applications and also because my Bernard set has a lever operated chuck rather than the scroll type which I find too slow for repetition work.

.

Thanks for the clarification, Max

MichaelG.

Crawford Multibore C-series W850 collets in a Burnerd LC15 lever chuck (normaly working with Multisize EC collets)?

I (still learning a lot 5 years autodidact home CNC guy) add my little findings, for reference of those who, like me, where not able to find this bit of information. …and also to be corrected if I'm wrong:

When shopping for Multisize collets, I found from time to time collet sets containing a mix of Burnerd Multisize and something looking to me as Crawford Multibore collets. Before reading in detail this discussion, I ordered some Multibore collets for my new old L15 lever chuck (besides a set of real Multisize EC collets).

After reading this discussion, I searched the Internet for the angles of the collets: 15 degrees for the Multibores (30 degrees included angle) and nothing found for the Multisize collets.

I was not sure if they where really incompatible, and having bought the material I had to try. When the material arrived, I was more careful, when putting the first Multibore collet in the chuck:

– The far end touches of the Multibore collet touches first the cone of the chuck, but with the spring mechanism and pushing very slightly, this looks rather good.

I decided to test to clamp 25 mm bar stock:

– The far end touches first

– Screwing the front nut a bit further and pushing the pivoting ring not very hard by hand, even without the lever of the lever chuck, the collet is able to grip the stock firmly.

Still not beeing sure about any difference in angle between the two collet systems, put a Multibore collet in the Multisize chuck. Leaving the collet empty, I closed the nut enough to make the lowest collet segment adhere to the chuck'ss cone. I put a lever indicator on the carriage to measure the angle difference (using the tangent function).

– There is a difference of about 2 degrees (4 degrees included angle). The Multisize EC collets must have an angle of about 13 degrees (26 include angle).

My temporary conclusion:

– Using Crawford Multibore W850 C-series collets in a Burnerd Multisize chuck (at least the LCxx models) is possible, but probably a bad idea because something bends, possibly badly.

Are there any other collets looking like Multibore collets and matching perfectly the Multisize chucks?

It would be nice to get feedback with your insights.