Forum sponsored by:

Tightening collets

Search for: in Thread Title in

David Clark 1	02/02/2010 09:49:40
3357 forum posts 112 photos 10 articles	Hi There I have a question from a reader who would like to know how to tighten the 2 Morse taper collets, the ones with 3 slots, so he can turn bar down. At the moment, they tighten up so far then rotate when he puts on a cut. I have used them for back stops but never turned or held cutters in them. Can anyone help? regards David
Circlip	02/02/2010 10:15:17
1723 forum posts	Trying to clamp too small dia.?? Worn bore?? Collets seem to have taken over as the universal "must have" clamping system, (bit like DRO's make super machinists) The clamping "Range" is a misnomer, as the collet can only Truely grip its "Bored" diameter and the only near universal collet is the "Rubberflex" (No affiliation). Regards Ian
Ian S C	02/02/2010 10:39:44
7468 forum posts 230 photos	I'v got one 1/4" collet,it will grip +0.005" and - 0.010". it rarely gets any use, but Davids idea of using it for a back stop sounds good. Ian S C
KWIL	02/02/2010 15:13:54
3681 forum posts 70 photos	I have a full set of Imperial and Metric 2MT collets for my Myfords. They work without any problem for the designated size. As Ian SC says the tolerance to tight.. I also use drawbar 2MT and 3MT collets to hold a spigot for for centering on a faceplate. ER series collets will hold a wider range of diameters quite succesfully. Personally I would never hold a cutter in any of them.
chris stephens	02/02/2010 17:54:59
1049 forum posts 1 photos	Hi Kwil, Do I take you to say you would not hold a cutter in an ER collet. If so, you have it slightly back to front, ER collets were made, and are only recommended by the makers, to hold cutters, not work. Or do you mean not to hold cutters in Morse collets? chriStephens
Robbo	02/02/2010 22:25:50
1504 forum posts 142 photos	Hi David, I may have missed the point here, but surely the simple answer to how to tighten a 2MT plain collet is to use a drawbar and tighten it up. As others have said, the collet bore must match the OD of what's being put in it. Robbo
Robbo	02/02/2010 22:26:03
1504 forum posts 142 photos	Hi David, I may have missed the point here, but surely the simple answer to how to tighten a 2MT plain collet is to use a drawbar and tighten it up. As others have said, the collet bore must match the OD of what's being put in it. Robbo
KWIL	03/02/2010 08:59:45
3681 forum posts 70 photos	Chris, I would not hold cutters in MT collets, I do use ER for cutters on small jobs.
Jim Whetren	03/02/2010 11:11:10
50 forum posts 1 photos	Hello David, To return to the original query, I would have thought that if the work was spinning, then either the MT socket was too short and the collet was bottoming before it fully closed, or the drawbar thread was too short; and binding before the nut was fully tightened. I would fit an empty collet and see if the slits start to close up if the drawbar is tightened. Jim
Clive Foster	03/02/2010 13:22:40
3630 forum posts 128 photos	Further to the comment from Jim W Due to the small taper angle MT collets need a lot of drawback to grip. Taper angle is near enough 50 thou per inch so a 10 thou contraction needs getting on for 1/4" drawback hence the need to keep close to the designated size. I'm amazed by the + 5 to -10 thou range reported by Ian. The small taper also means they are very inefficient at gripping things. Much of the draw bar effort goes in overcoming friction as the collet draws back into the socket. Be worth checking that the bore behind the collet is a bit larger than the standard small end MT 2 diameter of 0.572" so the collet can pull back into it. Something like 0.59" to 0.6" would be desirable. Clive
Hugh Gilhespie	03/02/2010 19:01:14
130 forum posts 45 photos	A slight variation on the collet tightening theme. I checked the runout on a piece of silver steel held in an ER32 collet on my mill today. The collet was a 7-8 mm size and I used 8mm silver steel in it so that the minimum tightening was needed. i tightened to my usual extent and was shocked that the TIR was 8 thou. The mill spindle TIR is about 0.2 thou and the collet holder was also around 0.2 thou, so it was all from the collet itself. I had to tighten much harder than I normally do to reduce the TIR to under 2 thou. OK, it's an Asian collet but even so I am surprised that it needs to be bullied so much. Lesson learned and I will take more care in future. Hugh
chris stephens	03/02/2010 23:59:15
1049 forum posts 1 photos	Hi Hugh, Welcome to the cynical "world of disappointment club". Regrettably just because it is a nicely ground collet, it does not mean it is a nicely ground accurate collet. Luckily for our end of the market, if you use a slightly naff collet in your mill you will not notice it. The odd thou or two run out of a cutter will not show up because you will almost certainly measure what you are making and alter the cut accordingly. CNC machining folks might have a different idea, but if they can afford CNC machinery they can easily afford top quality collets to match. (if you detect a note of jealousy, you are clearly quite perceptive) Where cheap and nasty collets are a real pain, is when you use them to hold work in your lathe. If the collet is not concentric it defeats the object in having one. The only exception to this is if you want a firmer grip than a 3 jaw can give. Even a dickey collet will hold work more firmly than a chuck, great if you want to cut a large and coarse thread with a die. The voice of experience has spoken. chriStephens

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Latest Forum Posts

*Oct 2023: FORUM MIGRATION TIMELINE*
05/10/2023 07:57:11
Making ER11 collet chuck
05/10/2023 07:56:24
What did you do today? 2023
05/10/2023 07:25:01
Orrery
05/10/2023 06:00:41
Wera hand-tools
05/10/2023 05:47:07
New member
05/10/2023 04:40:11
Problems with external pot on at1 vfd
05/10/2023 00:06:32
Drain plug
04/10/2023 23:36:17
digi phase converter for 10 machines.....
04/10/2023 23:13:48
Winter Storage Of Locomotives
04/10/2023 21:02:11
More Latest Posts...
View All Topics

Support Our Partners

Shopping Partners

Subscription Offer

Latest "For Sale" Ads

Reeves** - Rebuilt Royal Scot by Martin Evans
by John Broughton
£300.00
BRITANNIA 5" GAUGE James Perrier
by Jon Seabright 1
£2,500.00
Drill Grinder - for restoration
by Nigel Graham 2
£0.00
WARCO WM18 MILLING MACHINE
by Alex Chudley
£1,200.00
MYFORD SUPER 7 LATHE
by Alex Chudley
£2,000.00
More "For Sale" Ads...

Latest "Wanted" Ads

D1-3 backplate
by Michael Horley
Price Not Specified
fixed steady for a Colchester bantam mark1 800
by George Jervis
Price Not Specified
lbsc pansy
by JACK SIDEBOTHAM
Price Not Specified
Pratt Burnerd multifit chuck key.
by Tim Riome
Price Not Specified
BANDSAW BLADE WELDER
by HUGH
Price Not Specified
More "Wanted" Ads...

Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues