Would this be possible?

[navycop]

At the MAPG I noticed the turn between center bushings. I know there are turners that don't use bushings between centers and use calibers. Then they turn the blank shy of "the bushings" to apply CA. Would there be a way for those of us that are caliber handicapped, to have bushings that are made under the "normal specs"? This way we can turn to bushings and still have room for a CA finish. Maybe even apply a decal and not worry about it being proud of the components...

 

[JTisher]

I never use centers, just harbor fright calipers, always on sale for around 10.00

Joe

 

[Rodnall]

Just turn or sand your bushings down slighty

 

[plantman]

Mike; Your bushings are always going to be the same size, it's your fittings that may change sizes from one kit to another, so even if you undersize your bushings they may not be correct for the finished size you want to obtain. If you are to the point of careing about the size of the buildup of your finish, you definitly need to purchase a calipers. Go to Harbor Freight and buy the Pittsburg digital readout caliper on sale for about $10, regular $24.95, it reads in both inches and MM with the press of a button, to get it for under $7.50 use the 25% off cupon. I just can't, for the life of me, see anyone turning anything that is based on finished diameter in MMs or thousands, without using a calipers. In answer to your question. Since I will often use my mini metal lathe, and I have extra sets of bushings, I will turn down or cone a set of bushings in order to get undersize. You have to remember that when you turn under size you are decreasing the thickness of your blank also. My solution to this is turn to size, sand to 1200, apply my finish, and resand to 1200. Now, before I polish my blank, I will run the lathe and take a metal file and just round over the ends of the blank down to the desired size, and polish. Or, after polishing the blank and squaring off the ends on the disk sander, I will take a file and camphor the sharp edge of the blanks and seal them with fingernail polish hardner. Don't buy a caliper with plastic jaws if you intend to take measurements with the lathe running, they will melt!! Just a wild guess !! In the end, I would never put my trust in bushings for exact measurements, unless you have measured both bushings and fittings !! Jim S

 

[Charlie_W]

Mike,
Go with Plantman on this. Yes to the Harbor Freight calipers.
I only use between center bushings or turn totally between centers if it is a pen I don't have tbc bushings for. I turn about 4 to 5 thousandths smaller than my finished size and then build back up with CA. I build the ca up larger than finish size and then turn the CA my final finished size. At this point I am ready for wet sanding, polish and buff.
I end up with a finished pen that is round and fits the hardware. The bushings are a guide to get close to the final size. They may or may not be exactly the same as the component pieces.
For me, it is not about how fast I can turn a pen but how good of a fit and finish I can possibly achieve.

Good luck!

 

[loydstuts]

OK guys, I'm gonna parade my ignorance here. What's a TBC bushing? I'm such a boon!

 

[Charlie_W]

OK guys, I'm gonna parade my ignorance here. What's a TBC bushing? I'm such a boon!

These are "turn between centers bushings". No mandrel is used. You will need a 60 degree dead center for the headstock and your 60live center in the tailstock.
The bushings have a 60 degree chamfer which the centers fit into. There is no play here as it is a conical fit between center and bushing.

These bushings are longer and extend into the tube farther as well as being machined to a closer tolerance to the ID of the tube. Both of these factors reduce play and the possibility of an out of round pen.

Mandrel flexing is eliminated, play between bushings and mandrel is eliminated and bushings fitting loose in the tube is eliminated........better fitting blank to hardware.

These are now available from The Classic Nib. They do not have these bushings for all kits yet but are working on receiving more as they are machined.
I think these are available in 60 degree only as well as 60 degree with a thru hole for a mandrel as well.
Laser Linez has some on their site as well. They are the company which machines these bushings.
Penturners Products used to machine these but does not have many available now. His day job keeps him too busy. Good problem in these days.

You can only turn one blank at a time but the increased accuracy is well worth it.
There are TBC bushings for the 7mm tube as well.

Hope this helps.

 

[The Penguin]

At the MAPG I noticed the turn between center bushings. I know there are turners that don't use bushings between centers and use calibers. Then they turn the blank shy of "the bushings" to apply CA. Would there be a way for those of us that are caliber handicapped, to have bushings that are made under the "normal specs"? This way we can turn to bushings and still have room for a CA finish. Maybe even apply a decal and not worry about it being proud of the components...

yes, JohnnyCNC makes them like this if you request it.

 

[kovalcik]

I use either TBC or regular bushings + calipers to turn my blanks down, then I put them on a mandrel with the cone type finishing bushings to apply CA. The cone bushings are beveled to work between centers, but I never seem to get everything turning straight without the mandrel.

 

[Charlie_W]

For applying CA, I just mount the blank between a dead drive center and a live tail center. Both are 60 degrees. No mandrel...one blank at a time...nice and true!