Burnerd Multisize collets vs Crawford Multibore collets

[Adam HarrisParticipant @adamharris13683]

Just an update after more investigation – apparently the Burnerd Multisize collets are slightly more accurate than the Crawford Multibore, but less robust than the Multibore. It is not uncommon to find the fingers chipped on smaller capacity Multisize collets (usually due to trying in error to hold a workpiece that is too short) . Multisize collets are no longer made and nor are replacement fingers, whereas Multibore are still made. Both systems can handle Hex workpieces but Multibore have the additional advantage of being available for square workpieces unlike the Multisize. Chucks for the Burnerd system were made predominantly for manual machines available with a wide variety of fittings so they are more common amongst hobbyists whereas Multibore are more common amongst professional CNC shops. The possible weakness of using perishable neoprene rubber in Multibore is not really an issue as the material is specifically designed to resist coolant of all types. It is not completely unknown for a user to complain that coolant could have damaged them, but replacement neoprene inserts are very rarely requested. Hope this is of some use.

[NealebParticipant @nealeb]

My lathe has both a 5C collet nose (with lever release – such luxury!) and also came with a Multisize collet chuck with a full set of collets – in their original box and everything! As an aside, the box has some surface rust from its past life but the collets are spotless from being kept in it.

With those choices, pretty obvious that I use the 5C when I can but you are restricted to fairly close-tolerance stock. Otherwise, it's on with the Multisize but the thing I notice most – especially relevant to small diameters where you want minimum projection – is that the collet nose is quite a long way inside the closer. Having to pull the work out a bit further aggravates the "can't hold short work" problem, of course. The larger capacity is sometimes very useful, though.

[Adam HarrisParticipant @adamharris13683]

Interesting. I have recently acquired the more conventional Multisize that is operated with the drill chuck style key which doesn't suffer that problem, however of course I would prefer the lever closer for a D1-5 if I could find one.

Edited By Adam Harris on 17/11/2020 11:37:43

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