Why Is It Sticking?

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Spec Grade

Spec Grade

Member
Joined
Oct 14, 2009
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78
Location
Maryland
I tried to turn a pen today, using a 7MM PSI mandrel. The pen blank got stuck to the mandrel like fur to a cat.
I literally had to beat it off with a hammer.
What's going on here?
 
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CA glue sets when two objects come in contact with the glue between. If there is any wet glue inside the tube, it will set when you slide it on the mandrel. Don't ask me how I know this!
 
If you had no problems fitting the blank on the mandrel, you didn't have to force it on, glue in the tubes is probably the answer. Depending on the temperature in your shop the glue may have not set completely and the heat from turning finished the job. Have enough blanks left over to do it again?:rolleyes:
Mike
 
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A couple observations.

First, have you gotten it OFF the mandrel??
If not, be careful how you hit it, the material is just as likely to come off the brass tube as the brass tube is to come off of the mandrel (DAMHIKT)
Second, a cool shop will not help glue set firmly. A couple trips around the mandrel, however, will add enough heat to really set that sucker!! Of course the closest thing to the heat (the mandrel) will be get the best adhesion.
Third: Trickling acetone down the mandrel, while holding it near vertically will help "unglue" a stuck mandrel

Hope these little tidbits help!
 
Over tightening the mandrell nut can cause the bushins to crimp the ends of the 7mm brass tubes making the difficult to remove. Also, aggressive turning which caused the tubes to spin on the mandrel can crimp the ends of the tubes as well. However what you describe sound more like CA setting up.
 
I too suspect the glue situation but any chance you used the wrong mandrel "A" or "B" with the bushings?? I don't do slimlines so not sure if there is both sets of bushings for that kit.
 
Whenever that happens to me it's because some glue got inside the tube. I use epoxy glue so I have found a drill bit that just fits inside the tubes and use it (turning by hand) to get the glue cleared out of the tube...since I started doing that, no more problems.
 
There was no wet glue in the tubes. I made the blank up about 3-4 weeks ago. My guess is it seized up from heat build up from turning it. I literally had to beat it off with a hammer. I gouged the bottom half of the one blank, but I think I can fix it. I guess I'll spray some WD-40 on the mandrel shaft before I turn any more pens.
 
If it happens again, drill a 7mm hole in a large scrap of junk wood, thread your mandrel shaft through the hole in that and snug it up to the seized blank, and hit the scrap wood instead of your good blank. Careful with the mandrel also, as it is very easy to get a bend in it, which renders it useless...
 
toddlajoie said:
If it happens again, drill a 7mm hole in a large scrap of junk wood, thread your mandrel shaft through the hole in that and snug it up to the seized blank, and hit the scrap wood instead of your good blank. Careful with the mandrel also, as it is very easy to get a bend in it, which renders it useless...
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Man, now you tell me. And I have several made up blanks that I cut too short. I should have used one of those instead of a hammer & chisel. Oh well, live & learn. :frown:
 
I don't buy the heat thing and still cannot figure out what you are saying. Sometimes I am a little slow when it comes to what people are asking. From what it sounds like is the bushings froze to the mandrel. It is the holes in the bushings that are the only thing that comes in contact with the mandrel. There is no way you are going to heat the bushings up hot enough to expand them to stick to a mandrel. Now if you heated the blank and they did not come free of the bushings and it is not a glue issue then a simple twist will break them free. There should have been no hammering involved. Like I said sometimes I have a hard time with picturing things.
 
jttheclockman said:
I don't buy the heat thing and still cannot figure out what you are saying. Sometimes I am a little slow when it comes to what people are asking. From what it sounds like is the bushings froze to the mandrel. It is the holes in the bushings that are the only thing that comes in contact with the mandrel. There is no way you are going to heat the bushings up hot enough to expand them to stick to a mandrel. Now if you heated the blank and they did not come free of the bushings and it is not a glue issue then a simple twist will break them free. There should have been no hammering involved. Like I said sometimes I have a hard time with picturing things.
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I was thinking it was just me that couldn't follow what happened.
 
JimB said:
I was thinking it was just me that couldn't follow what happened.
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I must be getting old and all is not ging to the top floor any more because in another thread here someone is talking about things spinning and I am not following that either. One person things are sticking and another person things are spinning. :confused: I have to rest.
 
Rather then use WD-40, which can stain wood or mess with acrylic. Wax the mandrel with furniture every once in a while. This will also help to keep CA from sticking to it.
 
jttheclockman said:
I must be getting old and all is not ging to the top floor any more because in another thread here someone is talking about things spinning and I am not following that either. One person things are sticking and another person things are spinning. :confused: I have to rest.
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:tongue:It's a very complex world, isn't it?:tongue:
(Said in my best therapist's "lie down right here and we'll start the meter" tone of voice)
 
My hands are up..I did all that stuff and not just one time!:biggrin: I can only suggest you throw in the towel now. Toss the mandrel and bushings in the trash. Call Johnnycnc and get a dead center and a set of bushings for whatever pen you are making. You just slide the right bushing into each end of the tube, mount it directly between the centers and have at it. Much simpler this way..and more accurate pens. I have glued, screwed, beaten, smashed, tossed, cursed many a mandrel!
 
nava1uni said:
Rather then use WD-40, which can stain wood or mess with acrylic. Wax the mandrel with furniture every once in a while. This will also help to keep CA from sticking to it.
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You took the words right out of my mouth! Wax the mandrel.
:biggrin::biggrin::biggrin:
 
I just had a thought (look out) you said you had to beat it off with a hammer, is it possible that your mandrel is bent? After beating the blank off it with a hammer, I would check it anyways.
 
I got rid of it. I put a new spindle in the MT. I guess I'll sand it down with some 400 Grit paper & wax it, or put some Slip-It on there.
 
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