Tube problems

[Checked]

Have I lost my mind are is there a difference.
Making bullet pens and thought I would get smart and order
long tubes from PSI, was really going to speed things up. Have always used BB's slimeline kits.
Lucky that I only did 6 cartridges ahead, but went to assemble and the twist mechanism will not go in, or shall I say it will not go in without buckling. Finally just put these aside, to think about it.
Any experience with different tube and inside diameter.
Thanks

 

[Fisherman]

First check to see if you have any glue still in the tube. Second see if you crimped the tube any when cutting. I have learned to swab out the tube with acetone before assembly. Hope it helps you. George

 

[ctEaglesc]

recently I had a problem in the other direction,tube was too large to engage the transmissiion in the top.
Pastor Bill experienced the same troubles.
Of the 3 suppliers I have SL components from I believe 2 of the 3 are interchangeable.
Not sure which is whic though.
FWIW.
I don't know which casings you are using, I came to the conclusion it was easier to order extra tubes for 7 mm euro stlye pens than to cut the 10" tubes down.
I still keep the 10" on hand, but the pre cut length works well.2&3/8ths I believe.

 

[Fred in NC]

It is easy to bend or crimp the tubes when cutting to size. I use a razor saw to cut them. They can be found at any hobby shop. The blade looks like a miniature back saw, and fits in a handle. Cuts brass just like butter. Link to this type of saw:

http://www.widgetsupply.com/page/WS/CTGY/X-ACTO-razor-saw-blade

To avoid crushing the tube, I made a jig, sorry I don't have a pic handy. What I did is use a piece of soft pine and cut it about the size of a pen blank. I drilled the hole as straight as I could. Then I slit the blank longways with a hacksaw on one side only. I put the tube inside, and put it in my vise. That compresses the wood enough to hold the tube securely. Then I cut the tube with the razor saw.

To clean the inside of the tubes I use a letter "D" size drill bit. It is .246" or just about the size of a mandrel. I just made a wood handle and epoxied the end of the bit in.

Hope this helps.

 

[knottyharry]

I have had this happen to me a couple of times. And each time it has ended up being glue as the culprit. I think the acetone is a good idea. I haven't tried that. But now I have a brass brush used for cleaning rifle barrels that I run through the inside of the brass tube. Then I taper the opening a little, and swab it with some 3in1 oil before I try pressing the transmission into the tube.
Harry

 

[Checked]

Thanks for the thoughts.
Rex

 

[RussFairfield]

You have just discovered why you always read the recommendation to NOT interchange parts from the various manufacturers. There are no dimensional standards among the kit manufacturers. All things that look alike aren't. All 7mm tubes are not the same diameter, and it isn't just the 7mm tubes. 1 or 2 thousandths of an inch can be a lot for a press fit. It follows that the manufacturers have adjusted the diameters of their fittings to fit the tubes that they use, but sometimes they miss it themselves.

These differences are also a problem when interchanging the tubes on the mandrels, because all mandrels are not the same diameter. Each manufacturer has adjusted their mandrel to fit the tubes that they are using.

 

[timdaleiden]

Russ,

I was surprised to find out recently that even 7mm drill bits from CSU and PSI are different. I would have thought something like that would be more standardized, but they are different.