Triple Start Tap & Dies ??

[LL Woodworks]

One thing great about this forum is the knowledge of its members and their willingness to share. Well - I need some help understanding something and possibly some advise.

Earlier this year I started the custom FP experience. Trying to keep startup costs down I have been making FP with the following thread specs:

- 1/2-28 Cap & Barrel
- M10 x 1.0 section - have also made some M9 x 0.75
- M9 x 0.75 cap & Finial

I enjoy this so much I think I am ready to go to triple start threads, at least for the Cap & barrel -- Mabey

My questions are 1) Is there a real advantage of X3 threads vs single start, and what are they? Are they cosmetic or functional advantages? 2) What would be the best size to purchase M14x.8x3 or M12x.8x3? Would M12 triples accomodate the M10 x 1.0 section threads?

As you know the triple starts are not inexpensive, I want to make sure of what I need given my design specs.

Once again thanks to all who help me with this.

 

[jd99]

I'll leave the sizes to those that are into kitless, but the functional advantage is that it will take less turns to remove the cap with a triple start vs. a single start.

 

[mredburn]

Besides Jd99's reply on their main purpose the m12 will accommodate a m10 x1 for the front section. How large a diameter are your pens, that is what will help define the size best suited for you if you go the triple lead route. You can use the m12 triple lead set on pens that are larger than 14mm by adding a step between the shoulder for the blank and the threads themselves. Say you have a 16mm diameter cap body, you make the shoulder 16mm, a step at 14mm, and the thread tenon at 12mm that way you don't have a large step down from the cap diameter to the threads. If you only make very large bodied pens the m14 triple lead may be all you need. If you make pens that are mostly around 14mm in diameter at the cap and the occasional larger pen the M12 is better suited to your needs.

 

[IPD_Mr]

Function wise a triple start is a good improvement when putting a cap on a pen. If you thread your parts so that it takes one full turn to secure the cap to the body, then you have a potential of 1-1/3 turns with a triple start. On a single start you can have almost 2 turns.

I may be wrong but I think that the triple is also a more secure fit when snugged compared to a single. Meaning it would be less likely to start unscrewing on it's own.

 

[Ed McDonnell]

In theory it takes fewer turns to thread a triple start. If you have a solid color pen or don't care about matching designs, then your real life may match theory.

But I want my designs to match and I find I almost always have to screw the cap on at least twice to get the designs to match up. The supposed savings of triple start just don't seem to be there for me. It's actually a pretty big annoyance. Maybe if I always used the same pen I would remember how to put it together, but I don't.

As far as being more secure, I'm not sure about that. It's been my experience that if a triple start begins to loosen it will loosen a lot faster and easier than a single start.

If triple starts had superior holding power, wouldn't all screw be multi-start? I wonder why more pens don't have snap fit or friction fit caps?

Just curious.

Ed

 

[azamiryou]

Essentially, you get more holding power per turn of the cap for a given thread size. Alternatively you can look at it as the cap screws on/off faster.

For example a single thread at 12 TPI would take three turns to screw the cap on 1/4"; with a triple-start, it would only take one turn to screw the cap on 1/4". Once screwed on 1/4", the triple-start has almost the same holding power as the single-start.

If triple starts had superior holding power, wouldn't all screw be multi-start?

Two reasons single-start is better than multi-start for ordinary screws. One is that the grip for a given length of thread is actually somewhat better with the single start. The other is that installing the screw requires lower torque. A screw is basically a ramp - the single-start means a much shallower ramp. Just as a shallow ramp makes it easier to push something up it (but you have to push over a longer distance), a screw takes more turns to move the same distance is easier to turn.

 

[skiprat]

It is my firm belief that the ONLY reason for multi threads is so the cap CAN be screwed on and off easier.
Think of the threads as a wedge. You will get far more torque out of a shallow single thread than you will out of three steep angle ones.
Didn't the Churhill have 4 starts? Damned cap always came loose!!

Another way to think about it is;
Say for instance the thread angle of a single is 5 deg
A similar 2 start would have an angle of 10 deg
A 3 start = 15 deg etc etc

Eventually, theoretically you could end up with a 30 start thread where the angle would be an almost 90 deg ( straight line ) so you can see that the more starts you have, the less grip you have.

I believe they originally used multi thread because they didn't want the cap to seize on or the the thread to be able to crack the cap in half.


EDIT; I just seen that Matt said the same thing

 

[IPD_Mr]

Thanks for clarifying that Matt. Makes sence now.

They are also a great help in lining up patterns or graining.

 

[skiprat]

They are also a great help in lining up patterns or graining.

With a single start they will always line up. With a 3 start you will only have a one in three chance of them aligning.

 

[alphageek]

They are also a great help in lining up patterns or graining.

Interesting. That's actually the exact opposite reaction I have with multi-start threading.

It never fails - If a customer picks up a pen that is triple start, takes off the cap, then in a minute puts it back on... they get confused why the grain doesn't line up. They actually have a 2/3 (66%) chance of it NOT lining up when they put the cap back on. The only way a triple start lines up perfect is if the pattern repeats a multiple of 3 (which is possible with a man-made blank, but pretty unlikely in natural wood).

The good part about that is its a great way to keep talking to the customer and describing the advantage (faster on/off) of the triple start threads.

 

[azamiryou]

They are also a great help in lining up patterns or graining.

With a single start they will always line up. With a 3 start you will only have a one in three chance of them aligning.

I think he's talking about construction, not re-capping the pen. When constructing it so the grain lines up, one thread will get it less than 1/3 turn from aligned; with a single-thread, it could be almost a full turn out of alignment. (At the beginning of the alignment process.)

 

[alphageek]

They are also a great help in lining up patterns or graining.

With a single start they will always line up. With a 3 start you will only have a one in three chance of them aligning.

I think he's talking about construction, not re-capping the pen. When constructing it so the grain lines up, one thread will get it less than 1/3 turn from aligned; with a single-thread, it could be almost a full turn out of alignment. (At the beginning of the alignment process.)

Well, in theory you should never be more than 1/2 turn from alignment (since if you are 90% off you're only 10% the other way).... But for me no matter what thread count, I have to line it up with the parts fully seated in their final spot to know where to put it. Being 1/3 closer wouldn't help me?? I'm not sure how you would get it spot on otherwise.

 

[azamiryou]

Well, in theory you should never be more than 1/2 turn from alignment (since if you are 90% off you're only 10% the other way).... But for me no matter what thread count, I have to line it up with the parts fully seated in their final spot to know where to put it. Being 1/3 closer wouldn't help me?? I'm not sure how you would get it spot on otherwise.

We're talking about taps and dies, so we're talking about making our own threads... which typically means the threads are in the same material as the pattern you want to align.

So, once the threads are cut, you can't change the relationship of the threads to the pattern. To change the alignment, you have to change how far the cap screws on. If the alignment is off by a half-turn, you need to allow the cap to screw on a half-turn farther.

Generally, it's much easier to get the cap to screw on a little more (by removing material) than a little less (requires adding material).

So for your first point, you're correct if you can adjust the alignment in either direction. Generally, you can only make the adjustment in one direction, so if it's just past aligned, you have to go almost a full turn to get it aligned.

For your second point, I assume you're talking about the threaded parts being separate from the parts that need alignment. So you can screw the threaded parts together, then align the patterned parts as you assemble them to the threaded parts. This works for kits, and also for kitless pens if your threads are on inserts, or if the cap screws onto the section instead of the barrel.

 

[alphageek]

Well, in theory you should never be more than 1/2 turn from alignment (since if you are 90% off you're only 10% the other way).... But for me no matter what thread count, I have to line it up with the parts fully seated in their final spot to know where to put it. Being 1/3 closer wouldn't help me?? I'm not sure how you would get it spot on otherwise.

Or not... Duh - forget all that... I was thinking of ASSEMBLY, not creation... With creation, you may need to cut back up to 99% of a thread rotation and triple start would give you only having to cut 32%...

 

[alphageek]

Generally, it's much easier to get the cap to screw on a little more (by removing material) than a little less (requires adding material).

LOL... Yeah.. I realized my flaw and posted the same time as you did! And I can attest how hard adding material can be, even if you can weld on (much of my real threading experience is metal work, not pen stuff and its been a while:bulgy-eyes

 

[alphageek]

They are also a great help in lining up patterns or graining.

With a single start they will always line up. With a 3 start you will only have a one in three chance of them aligning.

Skip - On your metal creations do you single or triple thread? (Not that it matters - I'd love to have one either way).

 

[skiprat]

Dean, I only use single now. Multi's just kept coming loose:biggrin:

 

[keithbyrd]

For aligning grain when screwinga triple start cap on I found the following generally works. Insert the nib into the cap until it touches the threads and left twist the pen until the grain matches. Left twist until you hear one click then screw on.

 

[BSea]

I only have the 12mm, and I really shouldn't have bought that. This is just a hobby for me, so that kind of expense is a little overkill IMHO. But if I sold a lot of pens, I'd definitely use the 3 start Tap & dies. Having said that, I love the way the cap goes on & off so quickly.

My advice is to make some & see what works for you, then if/when you want to go with 3 start T&Ds, you'll have a good feel for what you need.

They are also a great help in lining up patterns or graining.

With a single start they will always line up. With a 3 start you will only have a one in three chance of them aligning.

Or they never line up.:wink:

 

[Ed McDonnell]

For aligning grain when screwinga triple start cap on I found the following generally works. Insert the nib into the cap until it touches the threads and left twist the pen until the grain matches. Left twist until you hear one click then screw on.

Hi Keith - I just tried your tip with the pens on my desk. For pens with a non-repetitive design it works great. For those with a repetitive design (back of the pen looks like the front of the pen) it's still a 50/50 shot.

Maybe I should design alignment marks into my pens. Something that wouldn't detract from the design, but would be unique for alignment.

Ed

 

[alphageek]

Maybe I should design alignment marks into my pens. Something that wouldn't detract from the design, but would be unique for alignment.

Ed

That is a REALLY cool idea and would be interesting to see. Kind of like the "locked/unlocked" symbols that go on things that twist locked. The challenge is making is subtle enough to not detract when closed (since they wouldn't be in line) yet visible enough to see when starting to close (when they should line up).

 

[duncsuss]

Maybe I should design alignment marks into my pens. Something that wouldn't detract from the design, but would be unique for alignment.

Ed

That is a REALLY cool idea and would be interesting to see. Kind of like the "locked/unlocked" symbols that go on things that twist locked. The challenge is making is subtle enough to not detract when closed (since they wouldn't be in line) yet visible enough to see when starting to close (when they should line up).

Reminds me of the dots that show how to position lenses when mounting them to a camera body. Line up the two red dots, bring the lens to the mount, and twist till it clicks.

 

[Ed McDonnell]

That is a REALLY cool idea and would be interesting to see. Kind of like the "locked/unlocked" symbols that go on things that twist locked. The challenge is making is subtle enough to not detract when closed (since they wouldn't be in line) yet visible enough to see when starting to close (when they should line up).

I'm thinking the following:

For a fountain, a mark on the inside of the cap that should be aligned with the nib when the two parts are brought together.

For a roller, a mark on the inside of the cap and a mark on the section.

The marks wouldn't be visible when the pen was capped. A mark on the section could be located so that it wasn't visible when the pen was being held.

Ed

 

[alphageek]

I'm thinking the following:

For a fountain, a mark on the inside of the cap that should be aligned with the nib when the two parts are brought together.

For a roller, a mark on the inside of the cap and a mark on the section.

The marks wouldn't be visible when the pen was capped. A mark on the section could be located so that it wasn't visible when the pen was being held.

Ed

That is EXCELLENT!

 

[alamocdc]

Okay, I've been following this thread with interest from the beginning and apparently I need a little schooling. Just before I left Ohio in 2008 a bunch of us went together and purchased 3 start T&Ds for making our custom FPs. IIRC these were for the threads in the cap and behind the section. I moved before I got a chance to use mine. Now if I understand this correctly, no one is using these now, Steven? If that is the case, that was a significant chunk of change I wasted. :frown::rain:And if that is the case, what size T&Ds is everyone using now for this? I have full sets of both SAE and Metric T&Ds, but I have a feeling what I will need won't be found in these.

 

[alphageek]

Okay, I've been following this thread with interest from the beginning and apparently I need a little schooling. Just before I left Ohio in 2008 a bunch of us went together and purchased 3 start T&Ds for making our custom FPs. IIRC these were for the threads in the cap and behind the section. I moved before I got a chance to use mine. Now if I understand this correctly, no one is using these now, Steven? If that is the case, that was a significant chunk of change I wasted. :frown::rain:And if that is the case, what size T&Ds is everyone using now for this? I have full sets of both SAE and Metric T&Ds, but I have a feeling what I will need won't be found in these.

Billy,

Skip is in a class all his own He makes pens differently than alot of people on here. And don't get me wrong, thats an EXCELLENT thing. But when it comes to pens of the "kitless" or completely custom, I would guess that more use 3 start than don't. I could be wrong (heck I proved it once in this thread already), but I would definately say that they only way you wasted money on 3 start tap and dies is if you CHOOSE not to use them. And if you do decided not to use them, I'll bet they wouldn't last long if you post them in the deal&steals free ads!

 

[BSea]

Okay, I've been following this thread with interest from the beginning and apparently I need a little schooling. Just before I left Ohio in 2008 a bunch of us went together and purchased 3 start T&Ds for making our custom FPs. IIRC these were for the threads in the cap and behind the section. I moved before I got a chance to use mine. Now if I understand this correctly, no one is using these now, Steven? If that is the case, that was a significant chunk of change I wasted. :frown::rain:And if that is the case, what size T&Ds is everyone using now for this? I have full sets of both SAE and Metric T&Ds, but I have a feeling what I will need won't be found in these.

Based on the number in the group buys the past couple of years, I'd think most use the 3 start T & D's. At least on the cap anyway. I'd like to have the 10mm 3 start for the section, and may buy it down the road, but I don't see a big need since it doesn't get the use like the cap does.

 

[keithbyrd]

For aligning grain when screwinga triple start cap on I found the following generally works. Insert the nib into the cap until it touches the threads and left twist the pen until the grain matches. Left twist until you hear one click then screw on.

Hi Keith - I just tried your tip with the pens on my desk. For pens with a non-repetitive design it works great. For those with a repetitive design (back of the pen looks like the front of the pen) it's still a 50/50 shot.

Maybe I should design alignment marks into my pens. Something that wouldn't detract from the design, but would be unique for alignment.

Ed

I guess I haven't had a pen with front and back "look alikes" so I hadn't thought of that but you would be right! Will have to ponder the idea of alignment marks!

 

[skiprat]

Okay, I've been following this thread with interest from the beginning and apparently I need a little schooling. Just before I left Ohio in 2008 a bunch of us went together and purchased 3 start T&Ds for making our custom FPs. IIRC these were for the threads in the cap and behind the section. I moved before I got a chance to use mine. Now if I understand this correctly, no one is using these now, Steven? If that is the case, that was a significant chunk of change I wasted. :frown::rain:And if that is the case, what size T&Ds is everyone using now for this? I have full sets of both SAE and Metric T&Ds, but I have a feeling what I will need won't be found in these.

Billy, I bought those taps and dies too. Yes they were expensive.
At the time I believed that I NEEDED them to make custom pens only because that was the norm. There were dozens of discussions about why everyone just had to have them.
Not once in any of those discussions was it ever mentioned about the ease you can crack a single threaded cap in half and the reason for multi threads was simply to ensure less pressure was transfered to the cap threads.
Don't forget that those old pens and of course many of the new ones are threaded directly into the vulnerable thin plastic.

A custom pen with metal threads ( like mine, for instance ) or even most kit pens simply don't need multi threads to protect them.

The arguement of multi threads allowing someone to align the grain is daft.
Irrispective of how many threads there are, grain alignment is dependent on the parts being pressed in while they are aligned during assembly
Thereafter, alignment is pot luck with multi threads ( 1 in 3 chance )and absolutely gaurenteed with single threads.

These days I'm getting more and more turned off by some of the kitless ( oops....sorry...componentless ) pens. Yes, they are beautifully made and ultra-light, but at what cost?
The material is often translucent and therefore often looks like completely different colours from section to section and then you can even see the butt ugly threads inside the cap.:bulgy-eyes::biggrin:

I'll get off my box now so you can shoot me:biggrin:

 

[LL Woodworks]

OMG !! - what a response - thanks for all the pros - cons and other comments of using x3 T&D. Man there is an abundance of knowledge and experience in this forum - Thanks ladies and gentlemen - more than likely, I will take the plunge for M12 x .8 x 3. If anyone has a set they need to loose, PM me.

 

[IPD_Mr]

I'll get off my box now so you can shoot me:biggrin:

No No - Back on the box you make a better target. :biggrin::tongue::biggrin:

All good point both pro and con for sure.

Now here is the big question for me. If they are not necessary (and they are in fact not) why have and do all the major pen companies use triple and quad start threads for caps to body? I mean seriously why would you go to the expense of replacing custom taps and dies as they wear out when you can use standard stock cheaper tooling?

Curious minds want to know.

 

[skiprat]

:biggrin:Jeesh Mike, didn't you read all the posts?

You are less likely to strip the thread or crack a cap with multi start threads than you are by using the same amount of force on a single thread.

The cap coming off or posting quicker is hardly an advantage. Nobody is going to be able to save up enough time to write their memoirs or anything

 

[alamocdc]

Ok, I feel better now. Thanks, Dean and Steven! And don't worry, Dean, having been raised by a child of the depression for much of my young life, I don't let anything go to waste if I can help it. My kids call me a hoarder as a result. LOL! At least when it comes to anything related to woodworking, turning (anything) and firearms.

Steven, I understand your frustration with some of the custom stuff being a bit too translucent (at least for my taste... and yours, apparently). Back when we bought these T&Ds most folks were only using metals, or things like Ebonite, Bakelite and Casein. IIRC it was because PR and most acrylics were thought to be too fragile to be reliable. It looks like that is not necessarily the case.

 

[Displaced Canadian]

Where's my gun I just saw a rat on a soapbox. :biggrin: I have to say that this is one of the most informative threads I've seen. I haven't bought a triple start set because I'm cheap. I see the advantage from a construction point of view but not the ease of opening thing. The last one I made is single start and can be opened with about 3/4 of a turn on a hot day. On a cold one it takes 1 1/2 turns. As for the seeing threads and each sections looking different colors, amen brother. That same pen looks great until you see it outside on a sunny day. Then you can see the threads in the cap and exactly where I changed drill bit sizes. Some day when she who holds the purse strings lets me I'll buy a set. My wife has a spending problem.... ME:biggrin:

 

[frank123]

FWIW, the only caps I've ever had come off in my pocket hae been tripple starts.

Not a big problem unless it's a fountain pen.

Personally, I like about 3/4 to a full turn to put a cap on with a single start threading and .75 pitch. I somehow seems classier to me, a reminder of days when everything didn't have to be done at high speed (but this is, of course, just personal taste).

 

[alphageek]

Where's my gun I just saw a rat on a soapbox. :biggrin: I have to say that this is one of the most informative threads I've seen. I haven't bought a triple start set because I'm cheap. I see the advantage from a construction point of view but not the ease of opening thing. The last one I made is single start and can be opened with about 3/4 of a turn on a hot day. On a cold one it takes 1 1/2 turns. As for the seeing threads and each sections looking different colors, amen brother. That same pen looks great until you see it outside on a sunny day. Then you can see the threads in the cap and exactly where I changed drill bit sizes. Some day when she who holds the purse strings lets me I'll buy a set. My wife has a spending problem.... ME:biggrin:

DUDE!! That is the first time I have seen anything where the temp outside changes the number of turns at all, much less doubling it!! Does the cap really expand that much??!

 

[Displaced Canadian]

When I cut the threads it worked properly. After I polished it the threads barely caught. I shortened the cap a bit and cut a little more threads and it worked but barely. Now that it is 25 degrees colder more of the threads are catching resulting in more turns to get the cap off. It's attempt #2 and will never leave my desk at home. Next time I'll polish a little less and leave the cap a little thicker.

 

[Dan_F]

I think you will find the main objection among fountain pen aficionados to single start threading is the three or four revolutions needed to cap and uncap a pen. For someone looking to lay down several hundred dollars on a pen, that can often be a deal breaker. In theory, less than than three or four revolutions can lead to opening in a pocket.

Dan

 

[aprayinbear]

How many turns?

I don't get it. Why would someone care how many turns it takes to attach the cap? It's part of owning a nice pen; the moment it takes to uncap the pen.

Now if a single will really crack more easily then a triple, then that's important. Anyway I'm just getting my feet wet. Can't justify a triple.... probably not for a long time.

Happy Turning