Sheaffer touchdown question

[MartinTenbones]

I have a wonderful sterling silver Sheaffer touchdown. 

 

It is missing the sac protector and it appears the screw holding the pump on to the end cap seems to be degraded to nothing.   It's still attached but I can't see the screwhead any longer.   Just shiny metal.

 

I had though maybe the sac protector was shoved right up there however I would expect to see the hole at the end down there.   There also is a hole in the pump from corrosion.   (Picture attached)

 

I think what I'll have to do is cut the metal pump sleeve to get it out since it will have to be replaced.   (Once that hole comes past the internal seal itn would lose the vacuum.) 

 

Then once it is out I'll cut the pump close to the screw head and make a slot in it to back the screw out.

 

I will then need to get a screw, pump sleeve, sac protector and a touchdown sack an seal kit to put it all back together.

 

Does this plan sound right or is there some other advice that I should follow?

 

Its a pen well worth saving

[Ron Z]

Well no - to a number of items.

 

First, these do not fill on a vacuum.  They are pneumatic fillers. Pushing the touchdown tube down into the barrel compresses the air, which squeezes the sac.  The notch at the top slips past the 0-ring and the pressure in the barrel is released.  The sac expands and ink flows into the sac.  That hole in the forward end of the TD tube is supposed to be there.  It releases the vacuum created when you pull back on the TD tube.  The sac guard keeps the sac from hitting the TD tube, but it also prevents the sac from expanding when you pull the tube back.

 

If the TD tube is stuck in the barrel, you should be able to pull it out. 

 

I do find some cases where the screw in the end is so badly rusted that the notch in essence disappears.  In cases like that I have to cut the TD tube off, and cut a new slot in the screw head.  The screw goes into plastic in the blind cap on these pens, so once you have a new slot, the screw should come out.  You'll need a replacement TD tube and sac guard.  A piece of bicycle inner tube makes a great rubber washer to go between the TD tube and the blind cap.  You should replace the 0-ring in the barrel while it's apart.  They're the same 0-ring used in a snorkel as is the screw.

[es9]

32 minutes ago, Ron Z said:

The notch at the top slips past the 0-ring and the pressure in the barrel is released.  The sac expands and ink flows into the sac.  That hole in the forward end of the TD tube is supposed to be there.  It releases the vacuum created when you pull back on the TD tube.

One thing I’ve always wondered—anyone know why it’s a groove at the end and not a hole? I assume there’s a good reason. 

[MartinTenbones]

Thanks for correcting me on how that works.  I had not noticed the hole in the tube on others pens.   Because this one isn't round anymore I mistook it for a flaw.

 

I still think I'll have to cut it off though. 

 

I appreciate you weighing in on this Ron

 

All the best

[Ron Z]

 

1 hour ago, es9 said:

One thing I’ve always wondered—anyone know why it’s a groove at the end and not a hole? I assume there’s a good reason. 

 

Because you want the pressure in the barrel to release before the stroke is finished.  It's releasing the pressure in the barrel, not just the tube.  The release is what creates the "chiff" that you hear near the end of the stroke.  It's an ingenious system, and about the most simple  and reliable pneumatic filler that I've encountered.  BTW, you can harvest parts from any of the Touchdown pens with the exception of the first year AKA  "fat" Touchdown pens. TD tube and sac guards are all the same.

[MartinTenbones]

OK I have a dolphin touchdown desk pen with a cracked barrel at the treads.  I think I'll harvest that one.