• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
  • PLEASE: Read the FORUM RULES BEFORE registering!

Need Advice About Lathe Collets

mikey

Active User
H-M Supporter-Premium Member
Joined
Dec 20, 2012
Messages
3,025
Likes
2,939
#31
This is a good place to remind folks, especially those who have never used a collet chuck, that there is nothing magic about a collet chuck. It has the potential to hold a work piece accurately, yes, but the contact surface of any collet is rather small compared to a jawed chuck. The collet will hold the work solidly enough to resist cutting forces up close to the chuck but the farther you are from the chuck, the more the potential for deflection. This is especially true if you are using a carbide tool, which will deflect the work piece all by itself. (EDIT: Not fair; a HSS tool will deflect the work piece, too, but not as much as a carbide insert will.)

It is wise to extend the work piece only as far as you need to, and if that extension is greater than 1-1/2 to 2 times the diameter of the work piece then consider using a live center to support the work. This matters when the work must be held to close tolerances but it is also good workmanship if that is important to you. In fact, this advice also applies to a jawed chuck as well.

Deflection is a real thing and it has several sources, primarily the size and material of the work, cutting tool and the way we support the work piece. By supporting the work piece properly we eliminate one factor and minimize the effect of the other. When accuracy matters and tolerances are tight, do all you can to minimize deflection.
 

Wreck™Wreck

Active User
H-M Supporter-Premium Member
Joined
Sep 29, 2014
Messages
1,918
Likes
1,461
#32
This is a good place to remind folks, especially those who have never used a collet chuck, that there is nothing magic about a collet chuck. It has the potential to hold a work piece accurately, yes, but the contact surface of any collet is rather small compared to a jawed chuck. The collet will hold the work solidly enough to resist cutting forces up close to the chuck but the farther you are from the chuck, the more the potential for deflection. This is especially true if you are using a carbide tool, which will deflect the work piece all by itself. (EDIT: Not fair; a HSS tool will deflect the work piece, too, but not as much as a carbide insert will.)

It is wise to extend the work piece only as far as you need to, and if that extension is greater than 1-1/2 to 2 times the diameter of the work piece then consider using a live center to support the work. This matters when the work must be held to close tolerances but it is also good workmanship if that is important to you. In fact, this advice also applies to a jawed chuck as well.

Deflection is a real thing and it has several sources, primarily the size and material of the work, cutting tool and the way we support the work piece. By supporting the work piece properly we eliminate one factor and minimize the effect of the other. When accuracy matters and tolerances are tight, do all you can to minimize deflection.
Many collet designs will hold the part better then a scroll chuck while not damaging it in the process, I have spun a good deal of drills and taps in turret lathes yet have never spun a part in a 5C collet machine, Warner & Swasey push collets are bullet proof for the most part.

Also Swiss style lathes do the cutting far from the actual chuck through a bushing that rotates with the spindle with no clamping force, the bushing must have enough clearance to pass the stock without hanging up, it works. This of course requires round stock that has already been ground to size. A basic explination of how Swiss lathes differ from conventional machines may be found here.

http://todaysmachiningworld.com/magazine/how-it-works-why-swiss/
 

The_Apprentice

Active Member
Active Member
Joined
Jun 14, 2017
Messages
45
Likes
7
#34
When I was in my young teens and working in my father's shop, 99% of the time the work was being carried out on collets. I will definitely pick some up in the near future, long before I get a 4-jaw chuck I think.
 

mikey

Active User
H-M Supporter-Premium Member
Joined
Dec 20, 2012
Messages
3,025
Likes
2,939
#35
I would get the independent 4 jaw chuck first if I were you. Far more useful and accurate.
 

wrmiller

Chief Tinkerer
H-M Supporter-Premium Member
Joined
Mar 21, 2013
Messages
3,076
Likes
1,073
#36
Depends on what you use your lathe for I guess. Can't remember the last time I used a 4-jaw chuck. It's been decades though.

Haven't even bothered to unpack the one I got with the 1340. YMMV... :)
 

wrmiller

Chief Tinkerer
H-M Supporter-Premium Member
Joined
Mar 21, 2013
Messages
3,076
Likes
1,073
#38
Says the guy with an Adjust-tru chuck! :D
Your right Mike. I do sometimes look at things from my perspective only.

If I DIDN'T have my PBA I would have to use my 4-jaw for barrel work, and any other operation that requires re-chucking a piece. Which is why I bought the set-tru. Hate using a 4-jaw... ;)
 

mikey

Active User
H-M Supporter-Premium Member
Joined
Dec 20, 2012
Messages
3,025
Likes
2,939
#39
Your right Mike. I do sometimes look at things from my perspective only.

If I DIDN'T have my PBA I would have to use my 4-jaw for barrel work, and any other operation that requires re-chucking a piece. Which is why I bought the set-tru. Hate using a 4-jaw... ;)
I hear you, Bill. I keep saying that my Adjust-tru just happens to have 4 jaws but I'm just kidding myself. One day I will own one, too. I tell you, you and Will (@darkzero) are really bad for my budget!!
 

wrmiller

Chief Tinkerer
H-M Supporter-Premium Member
Joined
Mar 21, 2013
Messages
3,076
Likes
1,073
#40
Budget?!? What budget?

The nice folks here on the forums (darkzero being one...) blew my so-called 'budget' into the weeds years ago. :confused:

Truth be told, I'm actually glad they did. Now that the money tree is gone (early 'retirement') I can no longer afford any major purchases. The one machine I didn't get was a small surface grinder. Oh well, such is life.

With any luck, my PM machines will last longer than I. :)
 

brino

Active User
H-M Supporter-Premium Member
Joined
Jan 2, 2014
Messages
2,842
Likes
2,615
#41
A basic explination of how Swiss lathes differ from conventional machines may be found here.
Okay, for the hobby machinists with Swiss lathes, please ignore my comments.
From the link provided by @Wreck™Wreck:

Expect to pay around $170,000 for a mid-range 20 mm (about 3/4″) unit.​

<whistle> I'm out! :frown:

But that was a great link Wreck, I never had the difference explained before.
Thanks!

-brino
 

benmychree

John York
H-M Supporter-Premium Member
Joined
Jun 7, 2013
Messages
993
Likes
559
#42
Have you seen a Jacobs Rubberflex Collet Chuck system? When I need to use a collet on my lathe this is my go to tooling. They were made with various back-plates to mount to your lathe, but I don't know if they have a size to fit your 8-1/2" machine

There is a Jacobs collet chuck that is smaller than the one pictured, it is the Model 50, and uses series 500 collets with a max capacity of 1" and an O.D. of about 6" on the handwheel
 

Zathros

Active Member
Active Member
Joined
May 9, 2017
Messages
106
Likes
127
#45
Thanks very much for the information. The LMS ER-40 4 inch diameter chuck will fit my lathe and is exactly what I was looking for. As Tom mentioned I would not be able to use the largest size collets as through hole but could hold shorter pieces of stock with them.
Thanks Brino for the welcome to Hobby-Machinist. The help and information has been exactly what I was looking for.
With my admittedly limited knowledge collets seem like a much more accurate way to hold round bar stock than a 3 jaw chuck and almost as easy to use (requiring at most a quick collet change). However on almost all of the youtube videos and blogs that I have seen 3 jaw chucks are used all the time and collets are very rarely if ever used. Am I missing something obvious?
You're welcome, I rather use à collet because it is better centered. Any workpiece round and max size of my lathe collet holder I prefer to use collets instead of the 3 or 4 jaw Chucks.
As one mentioned à good but mostly expensive Chuck Ok but collets are quicker removing worpieces and better centered for lot less money.
Just My 2 ct
Grts
T


Verzonden vanaf mijn iPhone met Tapatalk Pro
 

Zathros

Active Member
Active Member
Joined
May 9, 2017
Messages
106
Likes
127
#46
Brino even à cheap 3jaw Chuck is more expensive here than à complete er25 collet set with holder. It depends where you buy off course and were you live off course but What is keeping you from searching outside the borders. I bought à few sets of the cheapest er series from 11 up to 35 and they deliver more satisfying results than default chuck from the lathe that cost me the same as the whole collet range I have. I guess Chuck are more expensive here in europe.



Verzonden vanaf mijn iPhone met Tapatalk Pro
 

Zathros

Active Member
Active Member
Joined
May 9, 2017
Messages
106
Likes
127
#47
Okay, for the hobby machinists with Swiss lathes, please ignore my comments. :)
I have à made in swiss lathe milling combi set. And their chucks are not that good as I like them to be. So therefor I use collets where I can. Even so I found out that à lot of their acesories are just imported from Some of the better Chinese factories. Which is cheaper to buy directly from the Oriënt side of this 3rd rock from the sun.



Verzonden vanaf mijn iPhone met Tapatalk Pro
 

Zathros

Active Member
Active Member
Joined
May 9, 2017
Messages
106
Likes
127
#49
Have never been to Rotterdam but have seen pictures that some friends took of your beautiful city - it is just stunning, especially at night.
That's why I love to ride My bicycle at night also. And make those parts myself often. And off course in lathe and milling forums.
For My other hobby astronomy it is less suited by light polution tho.


Verzonden vanaf mijn iPhone met Tapatalk Pro
 

darkzero

Global Moderator
Staff member
H-M Supporter-Premium Member
Joined
Nov 27, 2012
Messages
2,995
Likes
1,713
#50
Says the guy with an Adjust-tru chuck! :D
I've got 2 Set-Tru chucks & a cheap chuck that I turned into a Tap-Tru but I still use the 4-jaw indy for times I have to dial something in where my Set-Trus won't work.

That and my 4-jaw is bigger than my Set-Tru chucks so it has a larger capacity & it grips much harder. I like my most used chucks to be one size smaller than my 4 jaw. I don't like cranking down on my scroll chucks hard so when I need to really hold something tight I'm happy to use the 4-jaw, plus it's fun dialing in. :)

I adapted a collet chuck to my lathe but honestly I never use it. I only use it when I'm working on really small stuff, 6-jaws hitting my knuckles is not fun, I don't want anymore of that pain. I have an ER chuck & it's slow to use. Maybe if I had a 5C collet closer setup I would use them more but I doubt I will ever go that route.
 

Wreck™Wreck

Active User
H-M Supporter-Premium Member
Joined
Sep 29, 2014
Messages
1,918
Likes
1,461
#51
One of the advantages of collets is that they do not vaporize coolant as a jawed chuck will, turn an 8" 3 jaw at 3000 RPM's with flood coolant and it creates a fog that will get everywhere.

Was turning 8-32 threads .225" long to a shoulder today in a 3 jaw, started at 1500 RPM's but the coolant was getting out of hand and backed it down to 1000. With a collet chuck I would have run it at 3000 without issue.
Pesky little buggers to run in a 15 X 40 lathe, only 40 parts however.

 
Container Above bottom breadcrumb