Blanks now don't fit on mandrel......

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Ray-CA

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Nov 14, 2020
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Okay, so now the brass inserts no longer fit on the mandrel. I've got the mandrel in the freezer now and have also sanded it lightly just in case I got some finish on it. Checked fit after 90-minutes and still no go. Anyone have any other ideas?

Thanks,

Ray
 
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ed4copies

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If I am understanding you correctly, the bushings (which are NOT brass) are not fitting into the brass tubes.

If this is correct, the highest probability is that you have glue in your brass tubes. When glue dries, it is clear, so you can't see it.
Use a penknife or a round file and rough up the inside of the tube, you will then SEE the glue--remove it. The bushings will, once again,
fit.

If, instead, you are saying the hole in your bushings is too small, try other bushings or "7mm" tubes. IF they also don't fit, sand down the mandrel some--not all mandrels are exactly the same diameter and "7mm" refers to the size of the hole you drilled, not the size of the tube.

Hope this helps,
Ed
 

Ray-CA

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The bushings fit fine. It's the brass tubes that don't fit. Same mandrel and kits I've been using all along. If the freezing doesn't work I'll try a more aggressive sanding on the mandrel.

Thanks to all......

Ray
 

qquake

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The bushings fit fine. It's the brass tubes that don't fit. Same mandrel and kits I've been using all along. If the freezing doesn't work I'll try a more aggressive sanding on the mandrel.

Thanks to all......

Ray
I'm confused. You say, "The bushings fit fine. It's the brass tubes that don't fit." That sounds to me like the bushings fit on the mandrel, but the brass tubes in the bodies don't fit on the bushing shoulders. If that's the case, why are you freezing the mandrel? You should try cleaning the inside of the brass tubes like Ed suggested. It might help if we knew which pen kit this is.
 

jttheclockman

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I think we all want to help but you need to give us more info because we are guessing out here. If the bushings go on mandrel then that is out. If you drilled a hole in a blank and glued in tubes and now they do not fit the bushings that you are sure the ones for the kit you are using then one of two things happened. Glue got inside the tubes and you need to clean it out using a knife or as Ed said a round file. a good light source will help seeing this. The second suggestion is the tube is out of round and this can easily happen because they are so thin. Could have something sit on them in package and caused this or you could have dropped them and they hit on edge. Freezing will do nothing to solve this. We need more help so we can help you.
 

magpens

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As John T. said, more info would be helpful. . You're probably talking about a slimline or other kit with 7 mm tubes, but we don't know for sure.

You say that the bushings fit on the mandrel with no problem ..... so does this mean there is no hardened glue on the mandrel ? . Perhaps.
Feel it with your fingers .... ( do you feel any glue lumps ? ) .... before you treat the mandrel with disrespect.

Abusing the mandrel is the last thing you want to do. . Sanding the mandrel is a bad thing to do becuz it will make the mandrel smaller in diameter.
The diameter of the mandrel (and the size of the bushings, both OD and ID) is important to get good accuracy when you turn the pen blank.
Treat them all with care and respect.

My strong suspicion is that there is glue inside the brass tubes. . This would require carefully cleaning out the brass tubes.

Or possibly, the tubes are not round, as John T. suggested might be the case. . Then the remedy is to get new tubes ... they can't be fixed easily.

To clean out the brass tubes you can use a "barrel trimmer", which you can purchase from PSI or other companies.
Make sure you get the right size for your particular tubes .... are yours 7 mm tubes ?
The internal bore of the 7 mm tube is about 0.245" ..... a 1/4" drill will probably not fit in there.
A drill of size 15/64" = 0.234" will .... a bit sloppily, but it might tell you if there is indeed glue inside, and it MIGHT help you clean the glue out.
You should be able to buy such a drill quite cheaply from a hardware store or even a big box building supply store like Home Depot, maybe even Walmart.
 
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tomas

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What are your constants and variables? I would consider the mandrel and bushings as constants since they don't change of their own accord between uses. The tubes on the other hand come included in each kit. I am sure at least a few of us here have received the occasional odd size tube in a kit. After checking for glue on the mandrel, bushings, and tubes, I would check the inner and outer diameters of the tubes and compare these measurements against what is listed on the kit spec sheet. Please, save the wild mandrel!

Tomas
 

BURLMAN

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If your “naked” brass tube slides on your mandrel before gluing, but not afterwards, you have glue in the tube as others have said. Hold your glued blank with some pliers, and slowly drill out the brass tube with a quarter inch or letter E drill bit. I have done this numerous times with 7mm pens with no loss of structural integrity to the finished pen. Only drill in about 3/4 inch on each end.
 

sbwertz

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I suspect he is talking about slimlines, which do not fit over the bushings, but butt up against them. do the brass tubes fit on the mandrel before you glue them into the blanks? If they do not, it sounds like you may have got some faulty tubes...I had some like that a couple of years ago. They were cheap chinese kits and the tubes were undersized.
 

egnald

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Greetings from Nebraska.

Most of the Mandrel Saver type mandrels are simply a collet chuck that holds a piece of "D" Drill Rod (0.246 inches in diameter). On several occasions I have had problems with 7mm tubes fitting too tight on my standard 0.246 inch mandrel, so I swap it out for a piece of "C" Drill Rod (0.242 inches in Diameter). The 4 thousandths difference isn't much but it has always done the trick for these tight 7mm tubes.

I buy both "C" and "D" Drill Rods from Granger and they only cost $6 each for 3 foot lengths, so my actual mandrels only cost about $2 each, so if they start running out of true or get galled up by tight bushings, etc. I simply swap them out for a new piece of drill rod. I cut them to length using an angle grinder but a Dremel with a metal cutting disc should work as well. Then I dress the ends and put a very small chamfer on them (essentially deburring them) using my disc sander.

Regards,
Dave
 
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I always, very lightly, chamfer my tubes after they've been glued into the blanks and trimmed to size. I've had this same problem in the past and found that the tube ends sometimes have a slight bit of brass scrap after being cut. I picked up this habit after starting to reload my own ammo. Had the same problem while trying to seat the bullet into the brass case after sizing the case.
 

Ray-CA

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"What happened to the OP? Did we scare him away?"

Nope, I don't scare.

Apparently I had some undersized tubes which fit when I turned the blanks but I tried to put them back on would not fit. Mandrel is straight (checked it on some 1/2" plate glass. Same way to check lifter rods by the way.) Did have a tiny, tiny burr on it but it cleared off with some 5000-grit paper.

I appreciate all the advise and help. Got it figured out and have turned a couple more pens without any trouble.

Thanks,

Ray
 
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PreacherJon

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Okay, so now the brass inserts no longer fit on the mandrel. I've got the mandrel in the freezer now and have also sanded it lightly just in case I got some finish on it. Checked fit after 90-minutes and still no go. Anyone have any other ideas?

Thanks,

Ray
Pictures would help
 

jttheclockman

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"What happened to the OP? Did we scare him away?"

Nope, I don't scare.

Apparently I had some undersized tubes which fit when I turned the blanks but I tried to put them back on would not fit. Mandrel is straight (checked it on some 1/2" plate glass. Same way to check lifter rods by the way.) Did have a tiny, tiny burr on it but it cleared off with some 5000-grit paper.

I appreciate all the advise and help. Got it figured out and have turned a couple more pens without any trouble.

Thanks,

Ray
So what was the problem and do not tell us a burr. You were sticking mandrel in freezer and things. What was the kit that was in question. Do not leave us hanging.
 

Ray-CA

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The mandrel came in a beginners pen turning kit from Rockler. The only thing that I found was, after measuring the tubes, was that that the ID was the tiniest bit undersized. No idea why they fit when I turned them but couldn't slide them back on.....

One of the worlds mysteries I guess.

I will be upgrading my equipment soon now that I've discovered how much fun I'm having.

Ray
 
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