Can someone identify this chcuk

[Swallowtail]

I very recently bought a super7 along with a load of stuff. one of the items is a small chuck, but which is very well made and smooth as silk in operation. Just wondered if anyone can identify it and what it's use is as I don't want to damage it. I have attached a few pics.

Thanks in advance.

[simplyloco]

Judging from the jaw lips it doesn't appear to have had much use. Burnerd is a quality name and those self centering chucks are very useful - just turn the knurled wheel at the rear- as there is no key to leave in the chuck!  Unless you are an apprentice that is. Ask me how I know...

[GordonL]

It looks like it may have the jaws in the wrong slots. The slot has a 2 on it and the jaw has a 3 on it.

[derekwarner]

A second hand Super7 [in good condition] will be a good buy 

I have not heard of Burnerd Machine Accessories, however is obviously a larger version of a Keyless drill chuck

This example appears to correctively have jaw No 3  in the correct chuck scroll position No 3

If either jaw was installed in the incorrect scroll position would result in a grossly eccentric  offset

Derek

[Jasonb]

Is there still not a risk of a tightening pin doing the same damage as a chuck key, I assume that is what the hole in the knurled ring is for. Or is there enough grip from these chucks when just done up hand tight (dependant on individuals hand strength)

[Jo]

I have not heard of Burnerd Machine Accessories,

Burnerd made chucks independently before they joined with another company to form Pratt-Burnerd.

Small lever tightening chucks (with that knurled bit for faster turning ) are very common especially in the smaller sizes. It is important to use a good fitting levers that are not very long so you do not damage the scroll, you will probably find they came with the lathe.

Jo

[Chipswitheverything]

Here is an example of the Pratt -Burnerd version, bought c 1985.  On this version, the jaws can be taken off via the screws and reversed on the carrier blocks beneath them, rather than having a seperate set of other jaws.  Lever scroll chucks like this are for fairly light use.  Dave

[Jasonb]

It's interesting that both the Burnerd ones shown don't appear to have pin/lever holes in the main body just the knurled ring. This is why I was asking about how tight they hold as the one I have for the Unimat like a lot of the small ones also have holes in the body, usually 3. Or is it a case of locking the spindle some otherway or using back gear when using the pin/lever in the Burnerd ones?

The Unimat ones also have reversible jaws with the teeth on the back being convex on both faces so only one set needed () rather than (((

[Chipswitheverything]

Hi Jason, yes, back gear would do it, though bothersome, unless there is a spindle lock as on a Myford. In fact, though not easily seen in my picture, there are two  ( just two, as per the ring as well )  holes in the main body as well.   I have been known to hold a jaw in an adjustable spanner for a bit more purchase...  Dave

[Jasonb]

Thanks Dave, much as I thought they need some form of levers or pins to do them up not just the knurled ring. Only ones I can think of that don't are the 5C ones with the much larger dia ring at the back which gives a lot more leverage