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turning between centers
Posted: Tue Apr 09, 2013 8:57 pm
by eagleta2
Hi all...
I am considering "losing" my pen mandrel and bushings and turn pens between centers. I've read that it will produce 'rounder' barrels and also more accurately sized barrels...since I'll be measuring them with a calipers. Keep in mind I still have to figure out what dimension to turn them to because sanding will reduce the diameter...and the CA finish I use will build up the diameter. Will have to fiddle around with it some
But in order to start I need to figure out the problem with the centers. I know I can get a 60 degree live tail stock center from the pen making supply store... but what about the drive center? Does someone make one for the as that mounts right to the quill? Or does it get mounted in the drill chuck.
All I have is the spur center... no lathe chuck (and would rather not buy one) and no screw center...
I appreciate your help.
Thanks
Geo
Posted: Tue Apr 09, 2013 9:43 pm
by eagleta2
Geez... I should really learn how to search better
This came up recently (late last year) and at that point it was discovered that the gizmo I want just doesn't exist.
So it appears I will have to commission the guys at work to make one...or buy a router chuck and use the router center thing that was mentioned the last time this came up.
I definitely want one that is made from material that is harder than the brass tube...I don't want to have to resurface it after just 3 or 4 pens.
Appreciate your ideas... I apologize for bringing up a recently dead question
Thanks
Geo
Posted: Tue Apr 09, 2013 9:49 pm
by WmZiggy
I think you are going to need a 4-jaw chuck if you are using square stock, or 3-jaw if you are starting with round. Drill chucks are not designed for laterial thrust so I don't recommend using them. I've turned a few pens and always used a mandrel, so I am having trouble envisioning making pens without using one.
Posted: Tue Apr 09, 2013 10:45 pm
by wa2crk
I think that you can do what you want with the SS screw chuck
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I think that I posted about a year ago. Hope it will work for you.
Bill V
Posted: Tue Apr 09, 2013 11:03 pm
by wa2crk
Here are a few additional pics that show the chuck mounted on a mini lathe.
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Hope they help
Bill V
Posted: Wed Apr 10, 2013 12:44 am
by eagleta2
Thanks bill... that is exactly what I want to do...well, sort of.
I was hoping to use a material that is harder than the brass tube, so I would have a durable surface that I wouldn't have to refresh.
I also do not have a screw chuck...
I'm thinking of making one that can chuck into the drill chuck...
Thanks for the help
Geo
Posted: Wed Apr 10, 2013 6:50 am
by Culprit
I only turn between centers if it's a one barrel pen such as a long clicker, bolt action, or an artist sketch pencil. I made a cone drive very similar to wa2crk out of oak except I dedicated my ShopSmith screw drive to it so I didn't index it like he did for repeatability when putting it back on.
The burnished oak is pretty durable and I have only had to resurface it once, but that was because my gouge wasn't sharp and I over tightened things so the blank wouldn't slip on the cone drive. As long as I keep my tools sharp and don't over tighten, then it works great. I also camfer the inside edge the brass tube with an X-Acto knife to remove burrs and ease insertion of the pen components.
I tried the steel router centering bit held in a ShopSmith router chuck and found it had more runout than my oak cone drive.
When I use a mandrel, I hold it in my Jacobs drill chuck. I haven't had any problems with side loading the drill chuck, but I've only used it for 30-35 pens so far. But now that I learned the importance of sharp tools and a light hand when sanding, it doesn't see much side load.
Posted: Wed Apr 10, 2013 8:03 am
by wa2crk
Here isa screw center on E-Bay 190822375938
It's in the Philly Pa area
BIll V
Posted: Wed Apr 10, 2013 11:23 am
by terrydowning
You can also use your drill chuck.
A set up similiar to Bill Vs above
1/2 bolt filed down
1/2 in brass or aluminum stock can be turned and filed as well. For best results index the chuck and dead center. I would not go smaller than 1/2 stock on the dead center though. Some of the tubes can get rather large.
I have one I made of 5/8" aluminum stock. I hold it with my collet chuck.
TBC tends to lead to Custom pens. I know you mentioned not wanting to purchase a chuck but If you are serious about turning pens, I do recommend an ER 32 collet chuck.
Beall collet chuck (A bit spendy but worth it from what I have heard)
Penn State Industries
Craft Supplies USA apprentice line
I believe the CSUSA and PSI are essentially the same chuck. for about the same price (about $90 the last time I looked.)
I have the PSI collet chuck and 5/8" arbor to 1" x 8 TPI adapter for mounting on the SS. I do recommend this combo for SS users.
You can also make bushings for TBC. On the sides that mate to the centers use a 60 degree bit to make the seat for the centers to ride in, cut a tenon the final diameter of your pen kit, cut a tenon the to match the ID of the tube you're using. I recommend using Delrin (acetal plastic) or UHMW, as the CA does not stick to this as easily during the finishing process. Tight grained hardwoods can also be used, but these are less stable and should only be used a few times as expansion and contraction will affect how concentric they are.
I have stopped purchasing bushings altogether, I have a lathe, sharp tools, measuring devices and decent skills so why buy what I can make??
Posted: Wed Apr 10, 2013 1:15 pm
by MikeG
I made a drive center from a shoulder bolt to get a good 1/2" diameter to put in my SS router chuck. Did the rough grind with a bench grinder and finished the angle with a file while it was mounted in the router chuck.
If you want to buy a drive "dead" center ready made here is a source:
http://www.penturners.org/forum/f172/custom-made-penturning-tools-accessories-92501/
Look at the bottom of the page. He has basically what I made for myself, only he has hardened his. Note I have no connection to him, only offering a possible source.
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