Closed End mandrel idea

Signed-In Members Don't See This Ad

davinci27

Member
Joined
Sep 5, 2008
Messages
511
Location
Franklin, GA
Closed End mandrel idea - Photos Added

I may not be the first to post this, but I haven't seen it so I thought I would put it up here.

So I wanted to make a closed end pen, but I didn't want to buy a bunch of closed end mandrels, so I had an idea to make some shims. I purchased a 7mm mandrel from Arizona Silhouette, then I glued up a scrap piece of wood to a standard 7mm tube. I then turned the blank down to the same diameter as the pen kit I wanted to use. My first one was a Jr Gent. After I had the blank turned down to fit inside the tube, I split it in half with the band saw. I then had a set of shims I could use with the 7mm mandrel.

--Edit For More Details--

So I added some more pictures. Basically you start buy gluing up and turning a blank into a sleeve so that it just fits inside the tube you are using for the closed end. I turned until I was close, then finished the sleeve to size with sand paper. You also want to trim the sleeve so it is shorter than the actual tube you will be using for the closed end pen.

Next you split the sleeve in half. I used a bandsaw to do this, but be careful you've got to get those fingers pretty close to the blade. It would be much safer to use a scrap of wood and make a jig to hold the sleeve.

Now you should have 2 shims. You are ready to put everything together. first take your standard bushing, flip it around and slide it on the mandrel. Next put the shims on the mandrel. Make sure the shims are put together so they match the split in the mandrel. When the mandrel expands, you want the shims to be able to spread apart. Then you just slide it all together.

If this still isn't clear, let me know. These shims were just my initial test. I'm going to make new set sometime in the next few days, and I can take pictures along the way to put together a more complete tutorial.


--End Edit For More Details--

The nice thing about using the shims and the 7mm mandrel is I can flip my bushings around and continue to use them as well. So now I have one mandrel that i can use with any kit. You can see my first closed end using this idea in the show off your pens section.

http://www.penturners.org/forum/showthread.php?t=40198
 

Attachments

Last edited:
Signed-In Members Don't See This Ad

alphageek

Former Moderator
Joined
Jul 19, 2007
Messages
5,083
Location
Green Bay, WI, USA.
That is a COOL idea! I have that mandrel and now have something new to try!!!!

COOL.. Looking forward to the pictures too, though.
 

VisExp

Member
Joined
Oct 1, 2007
Messages
2,739
Location
Palm Coast, FL, USA.
That's a great idea Ben. I have a closed end mandrel for Baron/Sedona. I might see if I can adapt it for the cap end, and also for both ends of a Jr. Gent.

I was thinking, instead of cutting the shim in half, of building a jig to allow me to cut only one side of it on my table saw. The advantage would be not having two halves of a shim to mess with and possibly lose.
 

davinci27

Member
Joined
Sep 5, 2008
Messages
511
Location
Franklin, GA
Originally I was going to leave about 1/2 an inch not split so I wouldn't have 2 pieces. Unfortunately with this one the brass tube was a little jagged and I didn't have a file I could get down into the tube. I had to split it so I could file off the burrs. I've come up with a pretty good idea for a safe way to split the sleeve, I'll probably try that this weekend to see if it works.
 

davinci27

Member
Joined
Sep 5, 2008
Messages
511
Location
Franklin, GA
Just a quick update. I changed my shims just a bit. Instead of completely splitting the tube, I split it from each end and leave a little space uncut in the middle. This seems to work even better. Here are a couple of pictures of the new shims and the shims on the mandrel with the bushing.
 

Attachments

cnirenberg

Member
Joined
Jan 26, 2004
Messages
2,700
Location
Fort Myers, Fl
Ben,
I like the new shim design. It looks like you will get a better grip on the inside of the tube. I did try your idea with a larger CE Mandrel and it worked great, I'm in for the 7mm size it is more versatile. Great idea thanks for sharing.
 

Ligget

Member
Joined
Jan 13, 2005
Messages
13,463
Location
Bonnybridge, SCOTLAND
Thanks Ben for taking the time to share your idea with us, it is an excellent one and I am sure it will be used by many members of this group including myself!
 

davinci27

Member
Joined
Sep 5, 2008
Messages
511
Location
Franklin, GA
the biggest benefit for me was the fact that I can use the bushings from the standard mandrel on the 7mm closed end mandrel. This new sleeve is much easier to use then the completely separate shims. I wish somebody with a metal lathe would make some of these.
Ben
 

Skye

Member
Joined
Jan 3, 2006
Messages
3,489
Location
Rock Hill, SC
I wonder if you couldn't whip this into a tutorial and squeeze it into the birthday bash somehow. "Best New Tutorial"? Is that a contest? If not, it should be.
 

davinci27

Member
Joined
Sep 5, 2008
Messages
511
Location
Franklin, GA
Yeah, I've got another tutorial I've been meaning to write and just haven't gotten it done. Didn't I hear we were going to a 25 hour day sometime in the future :biggrin:
 

workinforwood

Member
Joined
Mar 1, 2007
Messages
8,158
Location
Eaton Rapids, Michigan, USA.
I found a small flaw in this whole set-up. I built it and it worked fine. But..there was a small fisure in the burl I was spinning. I put a couple dabs of CA over the fisure to seal it up. Can anyone guess the result? If you guessed that the wood insert became glued to the inside of the tube and could not be removed without destroying the blank..then you are a winner! So...if you use the method proposed in this thread, and even if you just use the proper mandrel...wax it really good so no CA can stick to it or else remove the blank and fix any problems!!!
 

davinci27

Member
Joined
Sep 5, 2008
Messages
511
Location
Franklin, GA
That sucks sorry man. Did the blank have a tube glued in it? I haven't tried this on a blank that didn't have a brass tube in it. I also make the shim short enough so they don't extend beyond the brass tube. I might try making some shims out of Derlin to see how that works.
 

workinforwood

Member
Joined
Mar 1, 2007
Messages
8,158
Location
Eaton Rapids, Michigan, USA.
yes, the blank had a tube in it. But it's a closed end and the wood is all fizured. thin CA can really travel..I'm sure it found a path between the blank and the tube then came through the closed end portion and back to the shim. It's like water..the leak in your roof can be on the opposite side of the house as the damage. I wasn't thinking..I could have prevented it in the first place.
 

Darley

Member
Joined
Sep 3, 2004
Messages
2,131
Location
Melbourne, Victoria, Australia.
Sorry by that Jeff, you should wrap the shime with glad wrap before inserting it ( I thin you guys call this sarran, any way is food plastic wrap )


I found a small flaw in this whole set-up. I built it and it worked fine. But..there was a small fisure in the burl I was spinning. I put a couple dabs of CA over the fisure to seal it up. Can anyone guess the result? If you guessed that the wood insert became glued to the inside of the tube and could not be removed without destroying the blank..then you are a winner! So...if you use the method proposed in this thread, and even if you just use the proper mandrel...wax it really good so no CA can stick to it or else remove the blank and fix any problems!!!
 
Top Bottom