Why WONT my Parker Vac Imp's cap line up? The pattern doesn't seem to match, and fully screwed down, the edge catches on my nails. How do I correct this?

Avoiding this problem one should always mark the initial radial position of the aluminum screw insert in the barrel, prior to its removal.
Doing so one has a reference to tighten the insert exactly to its initial radial position.
But even doing so sometimes one can still feel radial offset of the seam edge with the fingernail.
This can be triggered by thickness variations between the old & new diafragm & small particles of the old diafragm remaining in the conical barrel seat.
In this case one has to equalize & smoothen the seam with a smooth nail file , followed by extra fine 6000 grit sanding paper & (Semichrome) polish.

So I should send it in for a complete overhaul before doing anything drastic?

If you vac filling system is fully functional - i.e. fills well- & the diafragm was recently replaced , you could leave it as is.
In this situation you could equalize & smoothen the seam with a smooth nail file , followed by extra fine 6000 grit sanding paper & (Semichrome) polish.
If you insist on having a perfect aligned pattern you can only gradually remove material from the blind cap end - using a smooth file - till the pattern matches.
When the pattern is only slightly offset, i.e when the blind cap should radially just go 5 or 10 angle degrees further to match, you could carefully try to screw the aluminum enclosure a little further in. Be careful, one can crack the barrel wall by applying an excessive locking torque;
Only my 2 cents, I'm sure real Parker specialists will zoom in & correct me if I would be wrong

On a pen like this? Definitely send it to a pro. I wouldn't risk screwing up an Imperial Vac.
If the blind cap lined up once, I can line up again. Might take some tweaking, but should be able to be done.
And I certainly wouldn't go sanding down the blind cap to match. A junky user vac, sure. An Imperial? No way.

Please do not sand it to correct the misalignment. If it was recently overhauled by a Pro send it back and request that they align the blind cap. If you have done the repair yourself, then you should be capable of aligning it yourself.

Marking the filler rotational orientation will get you close, but not always. Ensure that the tapered seat is free from any residue of the old diaphragm and then reinstall the filler unit. Turn it until it is snug, check the alignment of the blind cap. If it is not aligned slightly unscrew the blind cap until you feel that it would be aligned. There will be a gap now between the barrel and the blind cap. Note how much of a turn backwards was required to align the blind cap. That is the difference that you need to further install the filler by. This should not be any more than about 3/4 of a turn, or you will risk cracking the barrel or buldging it. If it is any more than this, there is something else the matter. The blind cap could be a replacement, or something is awry in the barrel's tapered seat (remaining old diaphragm) or the new diaphragm has slipped over the stop on the fillers tapered seat.

Remove the blind cap, tighten the filler by whatever slight amount was needed. Retry the alignment and you should be alot closer. It really is a feel thing though as well. On the Pearl colors the shading of the blind cap can give you an indication of where it should be aligned (if the blind cap is original). The barrel and blind cap were originally made from one piece, so the laminations should line up at some rotational alignment.

Cheers,
Sean

Whoops, It looks I've given bad advice,very sorry for that, and thanks Nick !
I thought we were talking about a normal vac, unfortunately I'm not familiar with an "Imperial" vac, in fact I've never seen one
I wonder how these look, I've Googled a little on "Vintage Parker imperial" but found nothing on it.

Gold filled cap, double jewels
I'll get it tuned by a restorer.

As far as I can see and was aware, the only real differance with an imperial vac is the cap. Of course I will be correctd by the more knowledgable sources here hopefully. Nice item BTW, you are one lucky, lucky person to have one of them.

et

Are we talking the blind cap here or the pen cap, I'm confused, please elaborate on the problem, at present I can't see what it is.

Vacs are generally fairly simple to sort out, and proffesional help, should only be required when manual dexterity and patience are wanting.

et

*re-read, and it is assumed that it it is the blind cap that is the problem*

There are two significant differences between the typical Vac and the Imperial vac. One is that the contour of the section is longer and thinner, and has the threads at the end of the section near the nib, instead of the barrel. The cap is metal, with the threads just behind the inner cap. The contour is also longer and thinner than the typical Vac. (I guess that makes it 3 differences).

The filler is the sub-deb, either streamlined or "disposable" found in the later vacs and 51s. Installation of the filler is the same, but the front end may be a little more fragile than the typical vac section. Getting the blind cap to fit properly would be pretty much the same as with any other vac fill pen.

Whatever the case, they're beautiful, elegant pens, and they're on my list of pens to look for.

Sean,

I've heard this before and wondered if it were true for two reasons:

1) The cut to sever the blind cap removes some material (the width of the saw blade). The filler threads are quite fine. Seems you might be off by half a rotation or so.

2) If the pen was shaped before the cut, the material removed would remove a bit of the slope meaning the diameters of the meeting planes would be slightly off. This could be defeated by doing the final shaping after the cut & remating, but problem #1 remains.

Any help? I'm obviously over my head, but obsessed Vac fans want to know!

John

This principle would only apply if the blind cap/filler threads and the filler/barrel threads were the same pitch -- which they are not.


I hadn't heard that before -- do you have a reference for this, or is it just an inference based on observation?

--Daniel

Daniel, I do not have concrete proof, which I know irks you. I do recall reading it here on FPN once from someone who has much more experience in these matters than I. Casual observation though on a few of the examples which I have does seem to bear the point out. There are distinct similarities in the pattern between the barrel and blind cap on several of the pens I have. When oriented correctly one can follow the same lamination around the barrel and the pattern matches across the joint.

I do not assert that I am 100% correct in this, and am quite willing to be proven wrong. Again the statement I made was based on corollary. I observed it on more than one pen, and made an assumption as well as repeating what I am sure I had read here somewhere once before.

Also, you are correct in your interpretation of my statment regarding the gap that I described. As the pitch is not the same but rather radically different this cannot work as I described. My intended message is hard for me to put into words, what I do seems to work for me. Then again I have never sat down and figured out the math of it, which while I am capable of doing it, would prefer not to as it usually ends up with me having a rather large headache. I do have success though in aligning the blind cap when it is out of alignment by visualizing where the cap is out and where it needs to be rotationally to get back into alignment. I then adjust the filler units rotation until it lines up when the blind cap is installed. I guess this is just one of those "seeing with your fingers" things that Ron talks about.

And Buzz, if the blind cap were cut prior to the final shaping and finish polish, would there be a step??

Cheers,
Sean

Thinking about you thinking about this gives ME a headache.


Let me ask this... so if there is no documentation that the Vacs were made from one piece, is there documentation that the pens were made from two? Or is the assumption that the pens are made from two pieces, so evidence is required to counter that? If the latter is the case, how did this become the assumption?

You must have seen me doing math at some point. It isn't pretty.

Good point though about proof of production method.

Cheers,
Sean

I am not aware of documentation one way or another, which is of little import given my lack of expertise in this area. I do not know whether there is a prevailing assumption among Vacumatic collectors regarding which method of construction was used (or whether both were used, for that matter).

I should note that whether there is any prevailing assumption (and what it might be) is irrelevant to the issue of evidence raised here. Evidence is required to support any assertion, whether in line with a prevailing assumption or contrary to it.

--Daniel

True. I guess I was referring to your statement that you "hadn't heard that before." I suppose now I understand that you had not heard the contrary either.

Exactly right.

--Daniel

Thanks guys! I'll be sending this to Ron Zorn or Binder, once I rack up the cash to restore it, plus a 51 demi with incorrect sac

Take an aspirin before continuing...

The barrel threads are 48 tpi. The blind cap threads are 36 tpi. (tpi = threads per inch)

The lead is the axial movement of the threaded part rotated one turn.

Thus, the leads are 0.0208 (1/48) and 0.0278 (1/36).

One revolution of the filler nut moves the stop point of the blind cap 0.0208 inches.
0.0208" of travel on 36 tpi results in a 0.75 turn of the blind cap. (Or more simply 36/48 = 3/4)

So, if you need to rotate the blind cap by 1/4 of a turn, you rotate the filler nut 1/3 of a turn. (Or 1/4 X 1/36 X 48 = 1/3) Now the tricky part. When you advance the filler nut 1/3 of a turn in (tighter-be careful) the blind cap stops 1/4 of a turn sooner.

Clear as mud right?

Todd

To my knowlege the Vac blind cap and barrel were NOT made from the same piece of plastic. Sometimes the pattern of the laminations will match, often it will not. What do you do with the Shadowave Vacs that have black blind caps? Or the bin full of blind cap for jr/major and maxima that I have?

What I do know from talking with Ernesto is that the 51 was finished with the filler installed, so that you have a perfect alignment. Parker repair manuals also say that shaving the barrel and blind cap to get them lined up is an acceptable last resort when they won't line up.

I find that changing the filler can cause things to fit differently, but not always. You should be able to get them pretty darn close, and most often perfectly matched. Once in a while though......