Question about work holding on metal mini lathe

Signed-In Members Don't See This Ad

FGarbrecht

Member
Joined
Aug 22, 2019
Messages
188
Location
NY
Need some advice on work holding methods for small parts on minilathe. I have a HF 7x10 with the standard 3 jaw chuck. The chuck has a little too much slop in the way it seats the workpiece (I can put in a cylinder pretty straight by eye but its not reproducible, always out by a few thou if I take the work out and rechuck it). The chuck jaws also make too much of the blank inaccessible to the tool, so I'd like to turn between centers. If I understand things correctly (I'm very new to this), I need to get a faceplate and lathe dog set, and either buy a 3MT dead center or machine a straight sided dead center to be held by the chuck jaws. Is this correct? Does anyone use a collett chuck on the mini-lathe?
 
Signed-In Members Don't See This Ad

bmachin

Member
Joined
Jul 28, 2013
Messages
443
Location
Owensboro, KY
You should be able to find lots of posts on turning between centers (for kit pens) on this site. For that, you don't need (or want) drive dogs etc.

You are right about 3 jaw chucks. They do not offer repeatability. If you want to take a part out and put it back with the same alignment back you need either an independent 4 jaw chuck (fussy) or a collet chuck. However, John Albert (Jalbert) turned for years using only a 3jaw chuck and only bought a collet chuck a year or so ago.

There are lots of tricks that you can do with a 4 jaw, but as I said they are slow because you need to indicate them in each time you put a part in.

I terms of collets, the MT3 collets that Bruce uses are inexpensive but are shallow as are the ER32 collet chucks that fit an MT3 taper. Little Machine Shop sells an ER32 chuck that bolts to the spindle of your lathe and allows you to hold parts of infinite length up to the ID of you spindle. Once you put it on, you will probably never take it off. You can probably find the same of similar at Amazon.


As far as ER collets ar concerned, I know that many here are satisfied with Chinese imports, but there are also horror stories ou there. Depending on your budget you might want to look here:


Hope this helps,

Bill
 

jalbert

Member
Joined
May 17, 2015
Messages
419
Location
Louisville, KY
You should be able to find lots of posts on turning between centers (for kit pens) on this site. For that, you don't need (or want) drive dogs etc.

You are right about 3 jaw chucks. They do not offer repeatability. If you want to take a part out and put it back with the same alignment back you need either an independent 4 jaw chuck (fussy) or a collet chuck. However, John Albert (Jalbert) turned for years using only a 3jaw chuck and only bought a collet chuck a year or so ago.
I’ve still never used it for turning. All my operations are done in the 3 jaw, and it gives me more than acceptable accuracy.
 

Mikeyt

Member
Joined
Jul 17, 2013
Messages
42
I use the mini lathe from harbor freight for turning between centers. I use collet chucks er 32 on my lathe I turned a 5/8 metal rod for a drive center. For me it was worth the expense for the collet chuck and the different size collets. I got them from little machine shop and on amazon. I love it and with the sizes of the collets I can turn everything I need and works great.
Before I tried to turn between centers or just try to turn straight with the 3 jaw chuck but always had issues. Now I know it is true and have no issues turning. It was expensive for me at the time but am so glad I did it and time and materials saved has paid for it many times over.


Sent from my iPhone using Penturners.org mobile app
 

JessePens

Member
Joined
Jan 10, 2019
Messages
85
Location
La Crescent, MN
I also use the Harbor Freight metal mini lathe and do all my penturning with a morse-taper mandrel with a mandrel saving on the tail side.

Rick Herrell made me an awesome tool rest that bolts down onto the machine that I would highly recommend. I'll have to take some pictures.
 

1shootist

Member
Joined
Dec 2, 2018
Messages
356
Location
Ennis/Waxahachie Texas
I use a Mt3 - ER32 collet chuck on my mini metal lathe...you can get the collet chuck and 11 orso collets as a set that are very reasonably priced in many places..and very easy to get repeat setups.
Turn between centers works very good too...Mt3 dead center and Mt2 live in tailstock.
I hate using a dog on it..too much of a pain.
 

More4dan

Member
Joined
Mar 17, 2016
Messages
1,489
Location
Katy, TX
I went a slightly different route on my 7 x 10 mini metal lathe. I started with a straight shafted dead center in my 3 jaw chuck. No dogs needed. The standard 3 jaw chuck limits the maximum diameter you can pass through the chuck to about 5/8”. I did bore my 3” 3 jaw chuck to 0.730”.

I turned my blanks round between centers to just under 0.730” and I could chuck all the way into my chuck so I could drill on the short lathe bed.

I have since removed my 3 jaw chuck and added a ER32 collet chuck that bolts to the same location as the standard chuck. This allows you to pass the maximum diameter through the head stock. A Morse Taper chuck doesn’t allow material to pass through. Its a major advantage of the metal lathe you might not want to lose when using collets.

I really like using collets much more than the 3 jaw chuck. Material doesn’t get “marked” and is more secure and more accurate. It takes a little more time but worth it.

Here is what I use and where I found the best price.

The Collet Chuck $50




The Collets set of 19 from 2mm-20mm $50:

IMG_0629.JPG

I’ve placed 19 orders here and received everything. Quality has been very good especially for the price. Let me know if you have any questions.

You will gain room on the lathe using the shorter collet chuck. I had to remove the clear chuck guard to take advantage of the space.

Danny


Sent from my iPad using Penturners.org mobile app
 

magpens

Member
Joined
Feb 2, 2011
Messages
10,585
Location
Coquitlam, BC, Canada
@FGarbrecht

If you want to go ahead with turning between centers, here is what I use on a mini metal working lathe ....

1) in the tailstock, a 60 degree pointed cone live center (integral with an MT2 in my case)

2) in the headstock, a diamond dust coated sharpening point that I bought from Lee Valley (but there must be other sources) ... here is URL:


Lee Valley used to sell a larger size diamond cone with a sharper point (I prefer that one) but I don't see it listed anymore. . The smaller one is adequate but I'd like the point to be sharper. . You have to drill small diameter, shallow holes in the (nicely squared) ends of your blank, unless you are turning a tubed blank, in which case you already have larger size holes (brass tube).

I use this arrangement with the 3-jaw chuck or 4-jaw chuck (NOT the independent jaws). . Reproducibility is OK because, for any particular work sequence, you have no need to open and close the jaws. . Removing and replacing between the cone centers has good reproducibility, in my experience.

You can, of course, use a parallel-sided dead center in your chuck jaws. . Or you can use a MT3 dead center in your headstock (after removing the chuck) and that will give you best accuracy and reproducibility.

Hope this helps you get started.
 

randyrls

Member
Joined
Feb 2, 2006
Messages
4,237
Location
Harrisburg, PA 17112
Frederick and ALL; If you decide to go with ER32 Collet chucks, buy the Metric set of 18 collets. They will hold any size stock. Fractional collets have "gaps" usually above 1/2" where none of them will hold the stock. Also there is a definite "order" to how to load the collet. See this article in the library.
 

frank123

Member
Joined
Feb 5, 2012
Messages
591
Location
Colorado
If you are trying for absolute concentric turning around a bore or axis, between centers using a lathe dog to drive the piece is the way to go.

If that is not your goal, you might consider getting a four jaw chuck for your lathe to adjust any material or odd shaped materials to run precisely with the axis you want to be concentric with (you can turn cams and such this way, or perfectly center square stock and other shapes as well). Four jaw chucks give a much greater precision than any three jaw chuck can over a wide range of sizes.
 

More4dan

Member
Joined
Mar 17, 2016
Messages
1,489
Location
Katy, TX
I’ve been able to turn pen blanks of all materials without dogs, just between 60 degree centers. I’ve even turned aluminum between centers w/o dogs. If it starts to slip, tighten the tail stock and/or take less aggressive cuts. An independently adjustable 4 jaw chuck will be the most accurate way to go if necessary, that degree of precision isn’t necessary for pens. As soon as you sand or coat you will have changed the precision of the piece.

Danny


Sent from my iPad using Penturners.org mobile app
 

bmachin

Member
Joined
Jul 28, 2013
Messages
443
Location
Owensboro, KY
What Danny said.

If you're interested, here are a couple of good videos on lathe chucks, turning between centers and concentricity from Blondihacks and This Old Tony:



For pens, the few thou of runout is immaterial; for other work, maybe or maybe not.

Bill
 

Penultimate

Member
Joined
Aug 22, 2010
Messages
662
Location
Bartlett, IL 60103
Like Danny I turn between centers with an MT3 dead center in the spindle and a live center in the rail stock. I have a 4 jaw chuck with independent jaws.

When I set up my lathe I mounted the chuck in each of three positions based on the screw position and measured runout. I found one position had the least runout. Mark that position on the back plate and the chuck so it goes on the same way each time. Also, try tightening the jaws using each chuck key location. I found the one of the locations consistently tightened the stock with the least runout.


Sent from my iPhone using Penturners.org mobile app
 

FGarbrecht

Member
Joined
Aug 22, 2019
Messages
188
Location
NY
Like Danny I turn between centers with an MT3 dead center in the spindle and a live center in the rail stock. I have a 4 jaw chuck with independent jaws.

When I set up my lathe I mounted the chuck in each of three positions based on the screw position and measured runout. I found one position had the least runout. Mark that position on the back plate and the chuck so it goes on the same way each time. Also, try tightening the jaws using each chuck key location. I found the one of the locations consistently tightened the stock with the least runout.


Sent from my iPhone using Penturners.org mobile app
I ordered a collet chuck for the minilathe, but I like the idea of using a dead center. Maybe I'll take some of that drill rod I have and make one :)
 
Top Bottom