PDA

View Full Version : Pratt Burnerd Multisize Collet System



Stuart Br
05-17-2010, 02:30 PM
Hi,

Anyone have any experience of the above system? Is it any good for the home shop? I am still relatively new to this game. Everyone talks about collets being the ultimate in work holding for round stuff in the lathe. Multisize looks good for its stepless flexibility.

Thanks in advance for any advice.

Regards

Stuart

djc
05-17-2010, 03:27 PM
Anyone have any experience of the above system?

Very good system. Very accurate. Somewhat expensive. Make sure you get a full set of collets as individual replacements are hard to find. Make sure you get a chuck key as it's inconvenient to operate without. EC or MC seem the most common size. Holds round or hexagon in the same collet.

Not good at holding short pieces or pieces with a larger diameter at the end inside the spindle unless they are longer than the collet. Compare this with, say, the ER system where the gripping length of smaller diameters is less than the length of the collet. Quite a long overhang from spindle nose.

jugs
05-17-2010, 03:57 PM
Yes, they are excellent, my set ranges from 1/16 1.5mm - 1 1/2 38mm. with good holding, I think the runout is about 0,0004" but my mounting system is such that the work is 7" forward of the front bearing (must change it).

But for accurate work, a collet directly up the spindle nose is always best, as the work is almost surrounded by the bearing.

gmatov
05-18-2010, 02:07 AM
I actually have one that I would like to sell. Problem is, to send it to you would be prohibitive, shipping wise.

I do believe that when I found their site, the price is astronomical.

Mounting is a clamp on the bedway with a butt with a pivot hole in it, similar to the clamp that holds your tailstock where it should be.

You don't drill holes and tap them in the bedway. You clamp it in place, if it is wrong, you loose it and move it either in or out from the spindle to make it correct.

Of course, you have to have a clamp that fits your lathe. My SB9 has a given height above the bed. Your Monarch will be different, so the fulcrom will have to be either higher or lower than mine.

THAT part will have to be customized to your brand/model of lathe.

If you weigh the sumbitch, the original cost, as on their website, is about equal to the daily price of Silver. ie, THEY want about 2500 bucks for a unit that weighs mebbe 12 to 15 pounds.. Well MADE, but, goddamn, that is a hell of a lot for a machine attachment.

Cheers,

George

Ian B
05-18-2010, 02:53 AM
My lathe came with an EC collet chuck integral with a D1-8 flange, range up to 1 3/8", no collets. I've since found pretty much all the round collets for it - 17 to 20 quid each on Ebay.

Lovely piece of kit!

Ian

EVguru
05-18-2010, 04:28 AM
I got an L00 mount version with a full set of collets when I bought my Harrison L5. The dealer charged 250, which I thought was quite reasonable. Most of the collets were still in their bags and packing grease, but there were a couple of duplicates. One the dealer was able to swap, the other I bought off ebay, selling the spare for more.

I find it very useful, but as has been said, it's not normally good for short stuff. There is a backstop system available, and I've sometimes knocked up something to fit there and provide a back support for the jaw blades so I can grip short pieces.

oldtiffie
05-18-2010, 06:38 AM
They look very similar to the "rubber-mounted" collet that I used on a brand new Dean Smith & Grace fulled accessorised lathe in my younger days.

The collet assembly did stick out a bit but was very good.

Try these:
http://www.toolingsolutions.com/catalogs/pba_6.pdf

http://www.google.com.au/#hl=en&ei=AW3yS-TPB4rk7AOEtfmPDA&sa=X&oi=spell&resnum=0&ct=result&cd=1&ved=0CBkQBSgA&q=Pratt+Burnerd+Multi+Size+Collet+System&spell=1&fp=320605b1f06788f9

Ian B
05-18-2010, 09:53 AM
Paul,

Have you seen a pic of the backstop assembly? I can make my own,. but before doing so it's always good to see the "proper" version.

Thanks,

Ian

gnm109
05-18-2010, 11:14 AM
Those specialty collet systems for lathes and mills are very nice if you can get the entire system reasonably. When I got my new to me Webb Mill last year, it was fitted with a "Snap Change" collet changer. This is the type that will release the collet from the spindle by simply raising the spindle handle to the top of it's stroke. It was really a neat unit. Unfortunately, I got no collets with it. When I contacted the company in Southern California, I was shocked to hear that the collets were over $100 apiece depending upon size. That was a non-starter.

I bid on two complete sets of Snap-Change collets on eBay over a period of a week and someone beat me out each time. So, I removed the special changer up top with the special drawbar and sold the parts on eBay and made a new stock drawbar. So much for Snap-Change. LOL. ;)

EVguru
05-18-2010, 11:41 AM
Paul,

Have you seen a pic of the backstop assembly? I can make my own,. but before doing so it's always good to see the "proper" version.

Thanks,

Ian

I've never seen one, but the website does say

'Collets may be fitted with end stops or ejectors for short components.'

The part number for an 'End Stop Location Disc' is apparently; 3151-30082

Malc-Y
05-19-2010, 06:38 AM
I have two Pratt-Burnerd Multisize Collet chucks, a KC15 that takes EC and MC series collets and a KC20 that takes the ED and MD series collets. The MC and MD range of collets have more gripping blades (usually 10) than the EC and ED range, which have six gripping blades. The MC and MD range are now no longer made but are often available on ebay.
The EC range covers sizes from 1/16" up to 1 1/2" in 12 collets and the ED range covers sizes from 1/4" up to 2" in 14 collets.
Both of my chucks have D1-6 mountings and I use them on my Colchester Triumph 2000 lathe and they are very accurate and repeatable.
All this equipment has been bought on ebay at what I regard as bargain prices! :D

Malc. :cool:

P.S. If anyone in the UK has an ED5 collet that they wish to sell, I need one to make up a full set!