8mm closed end options?

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Dan Masshardt

Dan Masshardt

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Good morning.

I want to turn some closed end seam rippers. They take a 8mm tube.

I have a 7mm expanding mandrel. Any thoughts on how to bridge the gap? Particularly if you've done something like this before.

My thoughts are - try to put a couple. Cuts in a 7mm tube one use it between or try tape over the mandrel.
 
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Dan Masshardt said:
Good morning.

I want to turn some closed end seam rippers. They take a 8mm tube.

I have a 7mm expanding mandrel. Any thoughts on how to bridge the gap? Particularly if you've done something like this before.

My thoughts are - try to put a couple. Cuts in a 7mm tube one use it between or try tape over the mandrel.
Click to expand...

Hi Dan - A 7mm tube is too small a OD diameter to do what you need. If you don't want to buy a closed end mandrel for 8mm tubes, you can make your own bushing for your 7mm mandrel. I've made mine from aluminum and if you have a metal lathe you can easily do it. If you don't have a metal lathe then a dense hardwood or delrin can work.

Mount whatever you are going to use for a bushing on your 7mm mandrel. Turn the OD so you get a snug fit in the 8mm tube. Cut one slit the entire length of your bushing. You are good to go.

If you turned your bushing with a snug fit, a wood bushing should last a long time. If your fit is not so snug you'll eventually end up with bushing pieces. Just make a new one if you do.

Not the only way to go about it, but it worked for me.

Ed
 
Hi Dan,
That is what I have on the lathe right now! I used a piece of 3/8" aluminum stock from Home Depot. I turned the end down to fit the tube with a snug fit. It just took a while. I tried HSS, carbide and then files. I finally got there. I used tail stock support while turning the aluminum.
The turned section extends the full length of the 8mm tube. You will notice I did not leave a shoulder for the workpiece to butt against. I want to be able to turn and finish the open end as well.
After turning and finishing, I will then part off the small bit at the closed end and finish that without tail support.
I am now using the kits from Woodcraft with the o-rings instead of the metal sleeve insert version I bought several years ago from PSI.
 

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Hey Dan,
Here is another one I had laying in the shop. This closed end mandrel has a #2mt on one end and the other end is whatever size and length you need. You can use some blue tape if your blank fits a little loose.
I turned some of these when doing a whistle turning project with two dozen bible school kids last summer.
You can also check on a pin chuck for the job. If CSUSA doesn't have one, Rick Herrell can fix you up.
 

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Dan,

You could mount a blank between centers turn it round and then shape the closed end as desired, but don't part it off. Put the blank in a chuck (pin chuck/collet chuck) and drill it out. Put an appropriately sized transfer punch in a collet/Jacobs chuck in the head stock, slide the blank on, mic the business end and then part the other end off.

Or ...

Contact Rick Herrell and have him make an 8mm pin chuck for you. Just send him a tube and he would be able to make one up for you.
 
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Dan -- making your own "O-Ring" pin (or pen spelling) using the instructions from SkipRat is pretty direct -- an does not lock up overly tight as sometimes happens with the "nail in the flat" style.

Have a "B" mandrel??? Use it to do a closed in with the same process (but different size) as Don Ward shows in his tutorial.
 
Since you plan to make multiple, why not pick up the 8mm expanding mandrel? I used one late last year to make a closed-end seam ripper in TruStone. The mandrel was well worth the slight cost (though I would've sworn the mandrel I have came with the ability to do both 7mm and 8mm).

I definitely prefer the look of closed-end seam rippers.
 

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TimS124 said:
Since you plan to make multiple, why not pick up the 8mm expanding mandrel? I used one late last year to make a closed-end seam ripper in TruStone. The mandrel was well worth the slight cost (though I would've sworn the mandrel I have came with the ability to do both 7mm and 8mm). I definitely prefer the look of closed-end seam rippers.
Click to expand...

Who makes an 8mm expanding?

I have the 7mm. I haven't used it yet though.

I know I could get a pin chuck made. I just prefer the expanding.
 
If you have a Beall Collet Chuck with a set of collets, simply go to Home Depot (with an 8mm tube in your pocket). Buy a wall toggle bolt with the rubber and "spider legs" that will fit into the 8mm tube, unexpanded (I think it's either a 1/4 or 3/8). Then purchase a longer screw that fits the expanding wall toggle that is long enough to give mounting room on the collet.

I think the total price for both pieces is about $2.

Run the longer screw through the center hole of the right sized collet from the rear of the collet. Thread the screw into the wall toggle until it sufficiently tightens in the 8mm tube. When you finish turning and finishing, remove the collet and unscrew the bolt holding the wall toggle.

DAMHIKT:) - works great
 
PenMan1 said:
If you have a Beall Collet Chuck with a set of collets, simply go to Home Depot (with an 8mm tube in your pocket). Buy a wall toggle bolt with the rubber and "spider legs" that will fit into the 8mm tube, unexpanded (I think it's either a 1/4 or 3/8). Then purchase a longer screw that fits the expanding wall toggle that is long enough to give mounting room on the collet. I think the total price for both pieces is about $2. Run the longer screw through the center hole of the right sized collet from the rear of the collet. Thread the screw into the wall toggle until it sufficiently tightens in the 8mm tube. When you finish turning and finishing, remove the collet and unscrew the bolt holding the wall toggle. DAMHIKT:) - works great
Click to expand...

I do have the collet chuck. I'm not totally picturing what the hardware is. Like a plastic anchor to hold screws in the wall?

Thanks.
 
No Dan, it is a long metal "bolt" thingy. As you turn the screw, the legs start to stick out, like a claw. I'll try to go to the shop in a few minutes and shoot a photo of one.
 
Dan Masshardt said:
TimS124 said:
Since you plan to make multiple, why not pick up the 8mm expanding mandrel? I used one late last year to make a closed-end seam ripper in TruStone. The mandrel was well worth the slight cost (though I would've sworn the mandrel I have came with the ability to do both 7mm and 8mm). I definitely prefer the look of closed-end seam rippers.
Click to expand...

Who makes an 8mm expanding?

I have the 7mm. I haven't used it yet though.

I know I could get a pin chuck made. I just prefer the expanding.
Click to expand...

John nailed it - the one I use is Penn State's "Grabber"....handles 7mm as well as 8mm...
 
TimS124 said:
John nailed it - the one I use is Penn State's "Grabber"....handles 7mm as well as 8mm...
Click to expand...

Do you like it? I thought I remember somebody say it wasn't so good.

If anyone reading has a 'grabber' they don't use, let me know. :-)

I'm planning on checking out Andy's method as well as turning a spacer sleeve for my 7mm mandrel.
 
If you have a set of transfer punches one of them is a perfect fit for the 8mm tube. File a flat near one end and make a pin chuck out of it. It can still be used as a transfer punch or diss-assembly tool.
 
walshjp17 said:
Dan Masshardt said:
Who makes an 8mm expanding?

I have the 7mm. I haven't used it yet though.

I know I could get a pin chuck made. I just prefer the expanding.
Click to expand...

According to the description on PSI's web site, the "Grabber" does both 7mm and 8mm.
Click to expand...

Have used the PSI Grabber and it works OK for 7 and 8mm. It has an expanding sleeve on it. They send an extra sleeve with it and I think I know why - it tends to bunch up after a few uses.
I found it very handy in making the modified slimlines as closed end per Don Ward. I've made several baseball bat pens using it which requires both 7mm and 8mm tubes.
The Grabber is a little pricey but works for me.
gordon
 
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Dan Masshardt said:
TimS124 said:
John nailed it - the one I use is Penn State's "Grabber"....handles 7mm as well as 8mm...
Click to expand...

Do you like it? I thought I remember somebody say it wasn't so good.

If anyone reading has a 'grabber' they don't use, let me know. :-)

I'm planning on checking out Andy's method as well as turning a spacer sleeve for my 7mm mandrel.
Click to expand...

It worked fine for me. Took a lot more tightening to get it to grip than I expected, but I was turning TruStone so no doubt that was a bit of a torture test.

Ultimately, it worked fine. It did what I wanted and let me easily create the closed-end seam ripper I posted earlier. I kept the tailstock engaged until the handle was shaped (except for a tiny bit holding towards the tailstock that was mostly turned away, then I removed the tail stock and only had to turn that little bit away without tailstock support).

I believe I sanded, polished all but that last bit that was connecting to the tailstock before cutting away that bit. I only had to sand/polish the very top without tailstock support.

That's pretty much what I expected so none of it seemed odd, bad, or unusual.

If you go with another option, I'd love to hear how it works out. Since you've used the 7mm expanding mandrel, you'll be able to compare both approaches first hand.
 
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