To my knowledge all pen turning mandrels are 7mm. Berea Hardwood has the thickest mandrels which are either A or B. Craft Supplies tad thicker than Penn State Ind mandrels.
I have never had trouble with Craft Supplies bushing fitting my Penn State mandrel.

Neither Craft Supplies nor Penn State bushing fit my Berea A mandrel without taking a round file to them. Would never attempt to make them fit my B mandrel.
Think Russ Fairfield gives diameter of mandrels at his web site. Could find those diameters at IAP several years ago.
If you are going to make Berea Hardwood kits recommend you buy either their A or B mandrel. Neither Crafts Suppiles nor Penn State Ind have an A or B mandrel.

 

To my knowledge all pen turning mandrels are 7mm. Berea Hardwood has the thickest mandrels which are either A or B. Craft Supplies tad thicker than Penn State Ind mandrels.
I have never had trouble with Craft Supplies bushing fitting my Penn State mandrel.

Neither Craft Supplies nor Penn State bushing fit my Berea A mandrel without taking a round file to them. Would never attempt to make them fit my B mandrel.
Think Russ Fairfield gives diameter of mandrels at his web site. Could find those diameters at IAP several years ago.
If you are going to make Berea Hardwood kits recommend you buy either their A or B mandrel. Neither Crafts Suppiles nor Penn State Ind have an A or B mandrel.

Thank you, wildwood.

So if if I wanted to give Cigar style pens a go, I wouldn't need a different mandrel, even though they use a 10mm tube? I was just assuming that since the tubes were thicker I'd need a thicker mandrel.

(I know these are really basic questions.)

 

I just turned my first "non-slimline" kit, the Mesa pen by Woodturningz.

The secret is you need bushings to match the pen kit you are making. The ones I got for Mesa are still a snug fit on the 7mm mandrel, but they have a step -- one diameter that fits into the end of the brass barrel tube, the larger diameter is your target size for the barrel.

HTH ...

 

Ohhhh. So bushings can be necessary for larger diameter copper tubes in addition to setting the width of the piece! That's the piece of the puzzle I was missing. Thanks, duncsuss! :smile:

 

Most pens can be turned on the standard A mandrel, you just need the correct bushings. Better yet forget the mandrel and turn between centers.
When I was still turning with a mandrel it was from Woodcraft and I had no problem with bushings from Berea or anyone else fitting it.

 

Berea A mandrel 0.247 and B mandrel is 0.291 list these diameters in catalog could not find at web site anymore. Not sure how old my catalog is, they stop sending yearly.

Assume Berea resellers the same, although price of mandrels change.
Woodcraft & Rockler once sold Berea kits exclusively, that might not be true today.
Depends upon franchisee as to what kits they sell.

Had to go back to 2004 post over at IAP to find these diameters, not sure if information still correct.

Craft Supplies 0.246 not in catalog or web site. They tell you do not guarantee their bushing or mandrel compatible with other vendors. Penn State .243 not in catalog or web site. Their mandrel saver tailstock center will fit any mandrel less than 0.245 or smaller.

Guys that use collet chuck often use ¼” D- drill rod as mandrels.

Yes, are talking thousands of an inch. You want bushings to fit snuggly on the mandrel, without forcing them onto the mandrel. Loose bushings on a mandrel will lead to problems like Out Of Round pen barrels.

Who makes the kits you buy does make a difference, also where you buy kits. Just about every vendor list 7mm mandrel only Berea uses the A & B mandrels at web-site they also us 7mm, but there is that silly thousands of a mm difference.

Do inspect you order when first get it. While never measure inside diameter of bushing do test fit on mandrel regardless if buying from Berea, CSUA, or PSI. Like many other turners do not use a mandrel anymore. I always measure outside diameter of bushings to insure have them oriented correctly. I always measure components so do not over or under turn pen barrels.

 

You just need bushings to fit the kit you want to turn. They should fit your present mandrel. You more than likely have an "A" mandrel since you were turning 7mm kits. Some bushings have a center hole to fit the thicker "B" mandrel & these are usually the lager pen kits. All your bushings that fit an "A" mandrel should have the same size center hole. Bushings made for each kit will fit the tubes for the kit. Bigger the tube bigger the bushing.

 

A and B Mandrels are typically the same length. "A as an 7mm and B" as an 8 mm. Pen kits come with many different tube (barrel) diameters, e.g. all the different bushings for each kit. Although the B mandrel had replaced the 10mm mandrel of the past, the A mandrel is becoming the leader. Bushings for this adaptation are called step-bushings.

 

There is a "Kit reference chart" at Hut Products that refers to the size and specs you may find helpful. Ameroclassic refers to the Berea "B" mandrel. General link is http://www.hutproducts.com/products.asp?dept=165
Kit Reference Chart link on top