Fuzzy math?

[Joe L]

I need some guidance. I turned a Big Ben pen using gemstone. Unfortunately my (now former) method of measure/cut the blanks resulted in both blanks being too short.

Specifically, the required 1 15/16" upper (cap) barrel digitally measures 1 29/32". According to my math, it is 1/32" short.

The required 2 1/16" lower (nib) barrel digitally measures 1 14/16". According to my math, it is 3/16" short.

Together the pen is 7/32" short. The result is the nib will not retract fully into the lower barrel.

How did this happen? HISTORY... Concerned about "blank blowout", I cut the blanks 1/4" longer than the tube length. That eliminated the blowout option. Unfortunately I was "sloppy" cutting the access off. A "smidgen" too much from each blank was the result.

I'm thinking if I can accurately incorporate 7/32" to the required length of the upper barrel (cap) and lower barrel (nib) I should have the correct assembled length for 2 modified pens.

One pen will have a 7/32" longer cap barrel and the other pen will have a 7/32" longer nib barrel.

To produce a visually pleasing pen. I'll put the "original" barrel on the lathe with the "new blank" to be turned.

Thus far, all "work" is in my head..... is my math correct...or what are some alternatives?

-joe L

 

[hewunch]

Joe, the only part you really need to worry about is the nib end. And there is no way to extend it. But you can shorten the refill by sanding off part of the plastic at the top. Or you can put something on the threads to stop the transmission higher (not fully seated) so it works.

 

[wdcav1952]

Joe, perhaps I am a bit lazy, which I have been accused of being a few/many times over the years.

To me, the best idea is to mutter, "Damn, I wasted a nice blank and a couple of brass tubes." Order another blank and some spare tubes which I believer turners should have in their tool chests anyway, and do the pen right this time.

 

[Fred]

Follow Cav's recommendations and you can't go wrong ... more broke maybe, but wrong ... NO!

Maybe now would be a great time for you to invest in a set of digital calipers? Try to get a set with the larger display as it makes reading through the dust a bit easier. Keep the caliper on or near your lathe and use them religiously.

I also fins that metric measurements are far more accurate than "our' measurement system by a long shot. At least division is easier since I don't have a ten figure decimal amount to contend with. Real quick what is 1/5 of 15/16" ...

 

[Joe L]

Yes, sanding off the top will help a bit... I understand about filling in a bit of the threads to shorten how far in the transmission will tighten... I'll have to see how to do that... probably with lock tight on the end of a paperclip....

Thanks.
-joe L

 

[Joe L]

I did order (and received) another blank... Regarding the digital calipers... I recently received those....and that is how I was able to accurately<?> measure the tiny differences and isolate the problem. Tools aside, now it's up to me to be able to use them correctly<grin>...

-joe L

 

[ldb2000]

Joe , you could take the lower barrel apart and put in 2 1/16" slices of some kind of veneer or filler in between the nib coupler and the tube and the same at the transmission coupler and the tube . Drill the veneer to fit the coupler not the tube then glue them to the ends of your blank . The 1/16" veneer won't affect strength of the joints and will make the barrel 1/8" longer . The extra 1/16" that's missing won't make much of a difference and the refill should retract below the end of the nib

 

[altaciii]

I'm with cav on this one. It really ticks me off when I waste a beautiful blank because I measured wrong. (only happened once...ok twice..) When I do I look at my options then see where I learned a mistake and start over.

 

[Joe L]

I like the veneer idea.... Except for my measurements, the actual pen turned out fine... so if I don't have to do a major turning modification... I'd like to keep it that way.

Regarding the "frustration factor" (I'm getting pretty good at that<sigh>), the good part is that I am refining how I approach the entire process. I appreciate the tips... keeps me from thinking there is only tool (the hammer) to fix the problem<grin>
-joe L

 

[ed4copies]

Definition of OOOPppppss rings

Joe , you could take the lower barrel apart and put in 2 1/16" slices of some kind of veneer or filler in between the nib coupler and the tube and the same at the transmission coupler and the tube . Drill the veneer to fit the coupler not the tube then glue them to the ends of your blank . The 1/16" veneer won't affect strength of the joints and will make the barrel 1/8" longer . The extra 1/16" that's missing won't make much of a difference and the refill should retract below the end of the nib

As far as I know (liar) Butch is the only one who ever came up with THIS solution. I routinely add embellishments to the end of my blanks -- but it's ALWAYS PLANNED!!!!

My method, however, drills the oops rings to normal size and a brass tube is inserted in the rings for the hardware. Either method will work, but Butch is smarter than me, so he does it more technically correctly.

Good luck, and add a few bucks to the pens selling price - embellishments ARE extra cost.

 

[ldb2000]

As far as I know (liar) Butch is the only one who ever came up with THIS solution. I routinely add embellishments to the end of my blanks -- but it's ALWAYS PLANNED!!!!

My method, however, drills the oops rings to normal size and a brass tube is inserted in the rings for the hardware. Either method will work, but Butch is smarter than me, so he does it more technically correctly.

Good luck, and add a few bucks to the pens selling price - embellishments ARE extra cost.

Yes , I am sorry to say it but I'm the only one here who ever screwed up and cut a tube too short . I know this solution works because I have had to use it many times :redface:
Had I been a smart as Ed I would have used a brass tube but it just never entered what's left of my mind :hypnotized: besides I'm too lazy to go through the trouble of cutting a 1/16" piece of brass tubing and gluing it into the veneer pieces :bulgy-eyes:
Never let it be said that I didn't do the least I could do
I don't call them embellishments because that sounds like I forgot something and had to embellish the blank to make up for it , I call them "Custom Made Blanks" so I can get even more money then Ed for them :tongue::biggrin:

 

[ed4copies]

You're fun, Butch!!