Question about bottoming tap for Jowo #6 nibs

[PenHog]

Hi,

I was just wondering whether anyone knows where to purchase a bottoming tap for Jowo #6 nibs. I haven't seen this for sale, and so I wonder if it exists at all?

Thanks,
Max

 

[Darrin]

A tap that size is available, a bottoming tap may be a different story.

 

[lorbay]

Why do you need a bottoming tap. Doesn't your hole go through?.?
Lin

 

[PenHog]

I know the tapered (starter) tap exists. But I've found a bottoming tap useful when threading for Bock housings, so I figured if I wanted to try Jowo, I would aim for the same setup.

Lin: I'm not sure I understand the question. When creating the section, I usually don't like to push the starter tap too far. The outside 10x1 threading of the tenon on the section ( for the section-to-body connection) doesn't leave me a lot of wall thickness. I find the bottoming tap useful for that reason; it lets me seat the housing at a good depth while keeping a good wall thickness.

 

[Carl Fisher]

Personally I've never had issue with the tap that is readily available which by definition would be a starter tap because of the lead in taper.

I use 10x1 for the majority of my sections and never had any problem with wall thickness. I even thread the back of my sections for a K6 converter which also uses an M7 tap (different pitch though). Plenty of thickness remaining.

 

[darrin1200]

@PenHog

A bottoming tap is the same as a starter tap with the first few millimetres ground off.
You can carefully use a grinder and sander to take of the first few partial threads, leaving you with a bottoming tap.

 

[PenHog]

A bottoming tap is the same as a starter tap with the first few millimetres ground off.
You can carefully use a grinder and sander to take of the first few partial threads, leaving you with a bottoming tap.

Hi Darrin M -- This is not my understanding, it's the other way around isn't it? The bottoming tap does NOT taper nearly as much as the starter. Here are a couple snap shots (attached) from Beaufort showing the difference for the Bock taps. You'll note the starter is tapered/pointed, while the plug is much less so.

So, I don't think I can just take the starter and grind off some threads to get the bottoming tap. Am I missing something?

EDIT: Yes, I am missing something, sorry for my confusion...thanks for this suggestion! That would probably do the trick.

 

[PenHog]

Personally I've never had issue with the tap that is readily available which by definition would be a starter tap because of the lead in taper.

I use 10x1 for the majority of my sections and never had any problem with wall thickness. I even thread the back of my sections for a K6 converter which also uses an M7 tap (different pitch though). Plenty of thickness remaining.

YMMV, I guess. For some acrylics and definitely the older materials, I've had the threads on the section break off due to lack of wall thickness at the point where the outside section threads meet the top of the section.

This can happen to me either when I'm threading inside the section, or once I've finished that and am turning down the section from the outside to get the right shape. In those cases, what I end up is something similar to what you found in your posting (attached); although, that material is indeed finicky.

Once I started using the bottoming tap, I no longer had this problem, I think because the point where the outside section threads meet the section top is not weakened. I've attached a sketch (not to scale!) of what I think is happening inside the section.

 

[leehljp]

I'm not into threading for pens just yet, but I agree with Darren. The first 8 - 10 mm on the starter is tapered, where as the bottom is tapered on the first 1-2 mm. The starter is not tapered over most of the entire length, although the photo kinda "looks" like it might be. The photo of the starter "appears" to have a gradual taper for most of the length but I would attribute that to photo deception (optical illusion), caused by the first 8-10mm real taper, which is very common. photo straight lines optical illusions

Most bottoming taps that I have used (and I haven't used a lot, but have used some) the bottoming taps are not tapered even on the first mm.

If you cannot find a mfg'ed bottoming tap, it would not hurt to make your own.

 

[PenHog]

I'm not into threading for pens just yet, but I agree with Darren. The first 8 - 10 mm on the starter is tapered, where as the bottom is tapered on the first 1-2 mm. The starter is not tapered over most of the entire length, although the photo kinda "looks" like it might be. The photo of the starter "appears" to have a gradual taper for most of the length but I would attribute that to photo deception (optical illusion), caused by the first 8-10mm real taper, which is very common. photo straight lines optical illusions

Most bottoming taps that I have used (and I haven't used a lot, but have used some) the bottoming taps are not tapered even on the first mm.

If you cannot find a mfg'ed bottoming tap, it would not hurt to make your own.

Hi Hank,

I agree that the starter is tapered for the first 8-10mm.

I agree the bottoming is tapered much less, only the first 1-2 mm (and this is what I've been searching for to purchase.)

I disagree that I can grind down a starter and get a bottoming tap...that does not seem possible...

EDIT: Ah, I see what Darrin M and you are saying now! ! Sorry for being slow, that's a great idea... Thanks!


Max

 

[Carl Fisher]

YMMV, I guess. For some acrylics and definitely the older materials, I've had the threads on the section break off due to lack of wall thickness at the point where the outside section threads meet the top of the section.

This can happen to me either when I'm threading inside the section, or once I've finished that and am turning down the section from the outside to get the right shape. In those cases, what I end up is something similar to what you found in your posting (attached); although, that material is indeed finicky.

Once I started using the bottoming tap, I no longer had this problem, I think because the point where the outside section threads meet the section top is not weakened. I've attached a sketch (not to scale!) of what I think is happening inside the section.

It's funny you should take that 2nd picture. That is one of mine and the reason it broke was because of heat. That material is extremely sensitive to any heat. It makes it very soft. I believe when that happened I hadn't even tapped the inside yet for the nib.

If you look at the IG post I even call out that it snapped doing a test fit. I will NEVER work with that specific material again.

As to your diagram, consider making a shorter tenon or a longer grip section to resolve this issue. There is no rule that says your section/tenon has to be x length. You adjust accordingly. For Bock nibs for example, I intentionally make longer sections with shorter tenons to put more meat in that section you are having problems with.

 

[Carl Fisher]

 

[Carl Fisher]

Sorry, one more visual. This my standard front section. You can see that even with a taper tap, there is plenty of meat left. I'm using M13 for cap to body threads but even at M12 it doesn't take away from the structural integrity of the core cylinder.

 

[duncsuss]

Take another look at the nib/feed housing that you are tapping for.

The threads might not extend all the way to the end of the housing - guessing the JoWo #6 has about 5mm unthreaded, you don't need to tap all the way to the inside corner. #5 nib housings do have threads all the way, but they are smaller diameter.

 

[PenHog]

It's funny you should take that 2nd picture. That is one of mine and the reason it broke was because of heat. That material is extremely sensitive to any heat. It makes it very soft. I believe when that happened I hadn't even tapped the inside yet for the nib.

If you look at the IG post I even call out that it snapped doing a test fit. I will NEVER work with that specific material again.

As to your diagram, consider making a shorter tenon or a longer grip section to resolve this issue. There is no rule that says your section/tenon has to be x length. You adjust accordingly. For Bock nibs for example, I intentionally make longer sections with shorter tenons to put more meat in that section you are having problems with.

Hi Carl,

I know that's your photo Yours is one the sites I visit regularly to see what the pros are doing (I hope you get set up again soon).

Back to the tap issue: what you say makes sense, and it means I just need to lengthen my section by a small amount. Between what Darrin, Hank, and you have said, it just goes to show that I am lacking in imagination. Thanks for the help and the diagrams!

 

[PenHog]

Take another look at the nib/feed housing that you are tapping for.

The threads might not extend all the way to the end of the housing - guessing the JoWo #6 has about 5mm unthreaded, you don't need to tap all the way to the inside corner. #5 nib housings do have threads all the way, but they are smaller diameter.

Thanks, Duncan! So, I'm convinced that I can purchase Jowo tap and give it a shot.

 

[Carl Fisher]

Here is the actual standard Jowo housing btw to Duncan's point. The threads only extend so far but with a starter tap you'll still have to run your threads into that runoff section or they will get overly tight. The key is to make sure you have the steps right on the front so that there is a positive stop that prevents you or a customer from over-tightening the housing and causing any sort of cracking or other various issues.

And don't forget, if you make a longer front section, adjust the depth of drill on your cap accordingly or you end up crashing the nib (ask me how I know LOL)

 

[PenHog]

Here is the actual standard Jowo housing btw to Duncan's point. The threads only extend so far but with a starter tap you'll still have to run your threads into that runoff section or they will get overly tight. The key is to make sure you have the steps right on the front so that there is a positive stop that prevents you or a customer from over-tightening the housing and causing any sort of cracking or other various issues.

And don't forget, if you make a longer front section, adjust the depth of drill on your cap accordingly or you end up crashing the nib (ask me how I know LOL)

View attachment 298818

Thanks, Carl! This is a clear explanation.