Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: Why were collets invented?  (Read 1333 times)

TCC

  • Guest
Why were collets invented?
« on: January 19, 2009, 11:22:56 AM »

When I first bought a hobby drill and was looking round, the collet type chuck seemed to be the item of choice for the better quality type of drill so I looked upon them whistfully and thought 'One day' :-).

Now I've got one, I'm not so sure...They just seem such a PITA compared to a chuck. When modelling, to change bits sometimes necessitates changing the collet and thus rooting round to find the correct one, unscewing the old, inserting the new fitting the collar and tightening, fitting the new bit and a final tighten. A chuck you just adjust either way, simple.

Is it price? As in it's cheaper for the maker to make 2 collets and a collar rather than them making a chuck?

Or is it accuracy? as in  a chuck may aquire grit that will throw out a 'claw' and thus off-centre what could be a .3mm bit?
Logged

Shipmate60

  • Global Moderator
  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,276
  • You bark - I will bite!!!
  • Location: Fareham
Re: Why were collets invented?
« Reply #1 on: January 19, 2009, 11:37:16 AM »

TCC,
For small mandrill sizes the collets are far more accurate for gripping and centering.
The grip of the chuck as the thread wears allows minor variations which isn't a real issue with larger sizes, but is in small sizes.
Another issue is cost, for the chuck to grip very small drills etc the "tongues" have to be very accurately ground.

Bob
Logged
Officially a GOG.

TCC

  • Guest
Re: Why were collets invented?
« Reply #2 on: January 19, 2009, 12:14:26 PM »

Cheers Bob, so even though collets are a 'cheaper' design, they are 'better'.

I wouldn't mind them so much but some of my mandrills? are different diameters and it gets a bit wearing (excuse the pun) swapping the collets everytime you go from cutting to grinding to sanding. I guess the (expensive) answer is multiple drills with 1 bit in each and no swapping.
Logged

pneumatician

  • Guest
Re: Why were collets invented?
« Reply #3 on: January 19, 2009, 08:55:30 PM »

If you want to hold accurately and securely collets are the only answer.  Far more grip than 3 jaws in a chuck remember its the friction between the tool and collet that transmits the drive.  All Machine Tools, Aerospace Drills etc use collets.  Tool shanks must also be precision manufactured however.
Chucks are inaccurate wether it be on a Lathe or Hand drill, to many moving parts with little surface contact. 
These points are not usually of concern when building models tho! unless of course you are machining the steam plant or prop shaft.

Steve
Logged

MikeK

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 986
  • Utter Bloody Chaos !!
  • Location: Fareham, Hants
Re: Why were collets invented?
« Reply #4 on: January 20, 2009, 09:19:59 AM »

I bought a three jaw chuck as an extra for my Dremel for the same reason ie collet swapping. Made life a lot easier/quicker  :D

Mike
Logged

dave301bounty

  • Guest
Re: Why were collets invented?
« Reply #5 on: January 20, 2009, 11:05:29 AM »

Collet,s are the stem and only way ,i have a watchmakers ,Boley 8 mm, and the collets i have for this ,a lot ,but you need them to get the precision that,s need in this work ,,the Swiss and British clockmakers were ,without doubt the finest,,  question answered..
Logged

Bartapuss

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 262
  • Deltic's Rule OK!
  • Location: Somewhere up North
Re: Why were collets invented?
« Reply #6 on: January 20, 2009, 11:16:36 AM »

As collets collets grip the stem of the tool fully they're ideal for machine tools in milling etc and as a drill type chuck only grips on 3 points only,and as such will probably come loose due to vibration or the tool may slide further up into the chuck thus causing defects in the work or a dangerous situation to accur.
Logged
Every time I learn something new, it pushes something old out of my brain - I says wot I likes and I likes wot I say!!!
Pages: [1]   Go Up