Tapping an ebonite section - manually?

[jmkeuning]

Can I hand-tap an ebonite section?

 

I have some ebonite sections that I would like to fit with some Pelikan nibs. The nibs almost fit, leading me to believe that the ID of the sections are just about perfect and that if I can cut some threads I will be good to go.

 

So, if I get the right sized tap, can I do this by hand?

[FarmBoy]

Can I hand-tap an ebonite section?

 

I have some ebonite sections that I would like to fit with some Pelikan nibs. The nibs almost fit, leading me to believe that the ID of the sections are just about perfect and that if I can cut some threads I will be good to go.

 

So, if I get the right sized tap, can I do this by hand?

Easily done by hand if you have the correct tap and a tap wrench. Each tap will have a correct drill bit that it pairs with. I recommend getting the bit as well and running it through the section first to clean up the hole before cutting the threads.

 

I can't help you with the tap size, Pelicans and I have never seen eye to eye.

 

Todd

[BKJ]

Can I hand-tap an ebonite section?

 

I have some ebonite sections that I would like to fit with some Pelikan nibs. The nibs almost fit, leading me to believe that the ID of the sections are just about perfect and that if I can cut some threads I will be good to go.

 

So, if I get the right sized tap, can I do this by hand?

 

 

Ebonite should be way easier to tap than steel or any other metals. As was already stated, drill to correct size then tap with the right thread tap. Be careful to tap as straight as possible if doing it by hand.

 

Please let us see pictures of the project, as I find this an interesting concept.

 

What pen are you modifying?

 

Good Luck,

 

Bruce

[Clydesdave]

Carefully examine the threads to make sure they are not "multiple lead threads". Multiple lead threads are those that start (intersect with the lead edge) more than once per revolution. Many pens use multi lead threads. They don't look any different to the casual observer. Be careful here!

 

 

[bgray]

This would definitely be easier to do before shaping and threading the exterior.

 

Also much easier to do with a lathe.

 

But you can do it, I'm sure. The problem is that the dimension is probably a strange diameter and TPI.

 

Which means probably around $100 for a custom tap.

 

If you own a lathe, you can make your own tap.

 

But the real obstacle will be finding a tap of the correct dimensions....not actually doing it.

[BKJ]

This would definitely be easier to do before shaping and threading the exterior.

 

Also much easier to do with a lathe.

 

But you can do it, I'm sure. The problem is that the dimension is probably a strange diameter and TPI.

 

Which means probably around $100 for a custom tap.

 

If you own a lathe, you can make your own tap.

 

But the real obstacle will be finding a tap of the correct dimensions....not actually doing it.

 

Do we know for sure if it is indeed, a strange size?

[fountainbel]

According my experience the tap specifications for the Pelikan nib assemblies are :

9/32"- 36TPI M400/600 Pelikan nib unit

11/32"-36TPI- M800 Pelikan nib unit.

3/8"-36TPI- M1000 Pelikan nib unit

Taps are all single lead.

As far as I know these taps are not standard, so they have to be made on special order in the "bottoming" version.

As Brian mentioned cost for a tap is around $110.00/tap.

I ordered a few more of the 9/32 & 11/32versions at the time, allowing me to sell a few for $80.00/piece.

Please contact me by PM when interested.

Francis

[jmkeuning]

Francis:

 

What is a bottoming version required for tapping a section?

[fountainbel]

A bottoming tap is used to tap as deep as possible in "blind" or "stepped" holes.

Such a tap has only a short fluted entry cone.

Since the extending feed on the Pelikan nib units normally fit in a smaller bore behind the screw thread, using a standard "fluted" tap would not cut the treads deep enough due to the long fluted entry.

Consequently a bottoming tap is not "centering" itself in the bore as easily compared to a standard tap, so manual tapping is surely possible although more critical as with a standard tap.

Francis

 

 

Francis:

 

What is a bottoming version required for tapping a section?

[Namo]

Amazing, the information one can find on this site! This is something I wanted to do for some time, fiting a vintage Peli 400 nib in a bigger ebonite body.

 

Today came the opportunity: the piston of my 400nn started leaking. Not much, but this is not the first time, and I guess it will need special care. So, well, why not? Let's try it!

 

The idea to tap the section was the first that came to my mind. But, well, seemed a little complicated; and this thread just proved that to be true. So, I tried.

 

I put the ebonite section into boiling water for about 10 minutes. And tried to put the 400 nib unit into it again, screw the unit like there actually was a screw inside the section... and it worked! the nib unit made its way into the section. It is not a perfect work, sure, and I don't know if any dammage occured to the nib unit once the ebonite cooled down. But the pen write. Nice size, wonderful nib... this might be heaven!

 

Now, I will have to write with the pen to see how the vintage feed behave with an ED filler... right now, the pen is very wet, of course. If the feed can't take the volume of the pen as it is now, I plan to fill part of the barrel with some material. It will still hold a lot of ink, and the feed should be able to manage the volume, since it was design to manage he volume of a piston filler.

[Splat]

This is indeed interesting, maybe vital information for a possible safety pen helix repair. I’ll try to be very precise.

 

I have a damaged safety pen with a nib to die for… tragically its helix is broken at the rear pin fixture point. However, on the opposite side the pin hole is intact and serviceable. The pin itself is intact, is made of steel, also intact and utterly stuck.

 

The tail cork needs to be replaced, (which explains everything).  My idea is to file the pin away on the broken side, (thus allowing me to remove the helix and cork cover and replace the cork with either a silicone ring or cut a new “cork” from a plastic wine “cork”)

Then, having silicone greased it, put the pen helix mechanism back together, (locating the Helix onto the unfiled pin side. And on the broken side, leaving a small gap.

 

The new idea is to drill and tap one of two holes into each of the remaining helix ends and so attaching the helix to the end cap stud rod by three points - the original pin and opposing it two newly fitted grub screws. 
 

As far as you can see does this possible broken ebonite fix seem to fly?

[Ron Z]

A picture of the broken part would be helpful.

 

Don't use a plastic "cork,"  (far too hard) and you can't use silicone grease with silicone o-rings.   Stacked Viton o-rings often work better than cork. 

[dipper]

A tap or die sold for general engineering use would be capable of cutting mild steel, and some harder metal alloys.

 

If your intended use is for tapping only soft materials then you can make your own hand-operated taps from steel machine screws.

 

Here is a tiny steel screw that I use to cut M3 threads into sheet brass for harmonica customisation. (The musical instrument, not some obscure brand of pen.)

Single flute, as this screw is so small, but on a larger screw you can grind more flutes.

 

Grind off the crests of the screw threads to a tapered outside diameter to make an easy-start tap.

 

And, given this topic has discussed difficulties in the subject of pen section tapping... and bottoming taps.... and centering.....

I suggest turning down the front inch or so of length of a bolt to remove all the screw thread and to be a smooth fit through the nib/feed hole part of the pen section (or up a much shorter distance into the body of a piston filler, staying short of the precision bore where the piston seal slides). That should solve the centering issue.

Then in the remaining bolt threads grind three cutting flutes.

And make two taps as above. One with a tapered cutting diameter, for the first tapping, and one without a taper for the second "bottoming" taper.

 

These home made taps do not have the speed and chip-clearing performance of a proper engineering product. Screw in just a little way, back off slightly, clear any swarf blockage, screw in just a little more than before, etc... but if you are making only one thread then that extra time is no problem.

Also, for hand use only. You need to be able to feel if the cutting process is beginning to bind.

 

[CS388]

Nice work, dipper. Thanks.