# Kitless Acrylic



## workinforwood (Apr 28, 2009)

I'm sure this is normal..first kitless and it's a flop.  But...let's examine it and discuss what did I do, how do I do it better, what are the proper steps.

I just want to start simple.  My plan is to use this brass compressor hose fitting.  I ground the end down so a parker tip will fit through it.  It still needs to be filed down on the lathe to be smooth, but this part is only important to know so that you know this will be my nib and the end result is a parker non twist with a cap.
  Barely stepped up in diameter from the nib, is a short thread section, then a shoulder so that the cap and the pen meet flush.
  I began by drilling out the pen to the proper inside length.  The assumption, because I did not use the chart Skip emailed me, was that I used the right size bit and would then tap the hole for the nib...oops.  The hole will tap, but barely, meaning the threads are too shallow to hold..first mess up.  I decided I can ignore this, re-pore another blank, turn it and jam it in the end then drill that, but that's a mute now that I broke the pen.  Anyhow, after trying to tap the inside, I stuck a dowel inside the pen.  The dowel was a decent tight fit.  I chucked the dowel into my drill chuck and the center into the scrap wood on the end.  I spun the pen round and spun the tennon for the cap threads.  I removed the pen and tapped the tennon, but my tennon again was just a bit small.  I think I was using a 12x1.5 tap.  It was almost ok, but just not quite.  It was however good enough to get buy for a first try.  I re-chucked the pen in the lathe and spun it out the way I wanted it to be.
  I drilled the cap section.  I then threaded the inside of the cap.  This was a big success this time.  The threading went perfect, nice deep decent looking threads.  I then stuck a dowel in and started spinning the cap section.  I was having a problem with chattering near the threaded area.  Didn't matter about how sharp my chisel and how light I took it, it just wanted to chatter and grab.  Not even turned to size, I capped the "pen" together.  The cap seemed to look like it was leaning to the side like maybe I was making an Italian pen, but the shoulder of the cap and pen line up perfect.  So the cap or the pen, or both are being turned off center is what I"m sure this means.  Looking at the threaded end of the cap, I can see one side thicker than the other, the pen, not so much.  I decided maybe I can spin the pen in capped mode on the lathe to straighten it out.  I took out the drill chuck and inserted a toothed center to grab the pen as I spun it.  It was going kinda ok, but wobbly and then finally at one point it, spinning at the cap in the same area as before where I had difficulties, the pen grabbed and flew apart.  The cap section cracked.  So the pen is lost, but not the experience.  The material used was alumilite.
  I think a bulk of my problems is the dowel chucked in the drill chuck.  This is pretty much the whole story, tried to give out all the details for your criticisms and suggestions.  Please give me all you got...I'm not embarrassed about it.

Oh..btw, there's no tubes, and the crud you see in the blank is just dirt from tapping and turning.  It is clear to see through.


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## skiprat (Apr 28, 2009)

Hi Jeff,
Here's my tuppence worth. It may or may not help.
The 12mm x 1.5mm thread is pretty coarse for my liking. But that is by the by.  The good thing about the metric system is you don't need a chart.
For a twelve mm external thread you simply turn the item to 12mm and then attack it with the die. It will cut the threads by the 1.5mm. But this coarse thread could be what is causing you the grief. 
For female threads, simply deduct the 'pitch' from the size, ie; 12 - 1.5 to give the drill size. 10.5mm in this case.
I would ditch the dowel. Even though you said it was a tight fit, you obviously had some slop around the threaded end. Instead, as you already have the tap and die, make a threaded mandrel to fully support the cap.
As you are using a standard 12mm, then this is easy to make from an old bolt too. You would need to put a 'collar' on it (the mandrel)to prevent the blank from screwing on too far while turning. If you still want to use a dowel then wrap some PTFE tape around it until you have to actually 'screw' the cap onto it. 
You need to plan the sequence that you will do the threading so that you will have the maximum material thickness. The tap will stretch (and perhaps crack)the cap material if its too thin.  Wrap several layers of electrical insulation tape to stiffen things up. The die will squash the body. Maybe use a dowel in the body when using the die. 
What methods are you using to keep the tap and die perfectly aligned with the material?

Before using the tap and die, wash them to get rid of dirt and oil. I use dishwash liquid to lube. 

Hope this is some help, but you have my email addy if you want any clarification:wink:


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## thewishman (Apr 28, 2009)

Jeff, that looks like a great first effort to me. The blank is cool and the overall look is good. Thanks for sharing the step-by-step, I may actually learn something (if I can get past the what-the-heck-is he-talking-about stage).

The brass hose fitting is a neat idea.


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## BRobbins629 (Apr 28, 2009)

Welcome to my world.  I have a box full of those.  A few ideas to add to Skippy's.  Staying on center can always be tricky and with kitless its even more important as you have seen.   I always drill on the lathe with a collet chuck and start with a centering bit.  While the blank is round and oversize I do my threading.  If I have an external and internal thread in the same area as the nib holder, I thread the inside first, plug it with a delrin plug and then cut the external threads.  Not sure if you are getting runout with the drill chuck, but if I can get the hole perfectly centered, I sometimes turn half a section at a time in a collet chuck, getting real close to final diameter.  The last bit and shaping is done with sandpaper using a pin chuck (or Skippy'e o-ring chuck).  

As for the angled threads, you should be taping with the blank in a collet chuck and the tap in a drill chuck in the tail stock. Just loosen the tail stock, turn the head stock by hand and slowly guide in the tail stock.  For male threads, ENCO sells die holders that will fit in either a drill chuck or morse taper.  You will rarely be able to cut straight threads by hand.


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## workinforwood (Apr 29, 2009)

ok, yes I cut the threads by hand.  I feel that the drill chuck might have some run-out, but the run out is minimal.  The dowel in the drill chuck gets crushed by the jaws and not necessarily crushed evenly all the way around, which could be the biggest problem of out of round.  These are good tips.  
  So I can drill a 12mm hole and tap it, then I should be able to buy a long 12mmx1.5 bolt, chuck the bolt and remove most of the threads on the end with a file and shorten the bolt if need be and I should be good to go...that's what I think I'm reading?  A bolt certainly would be more ridgid.  I'll call enco and get a die holder.  I saw the pic Steve posted not long ago as to how he tapped/die'd the blank, but couldn't figure out how he got the die to fit the lathe.


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## cnirenberg (Apr 29, 2009)

Jeff,
I ended up making my own threaded chucks for the tubless pens to keep the center true.  I got some bolts from the hardware store, the diameter a bit larger than what I needed, turned (filed really)them down and then threaded with the dies by hand.  Threading standard bolt steel wasn't a problem, however the stainless bolt was a task.  Nice job on the pen.


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## workinforwood (Apr 29, 2009)

Thanks guys.  I'll order that die part and find myself a cardboard box to collect my broken pens into.:biggrin:

How about this question now.

12x1.5 is the die.  so 12mm by what..1.5 threads per centimeter?  is 12x1 more threads.  I used 1.5 because I thought it was more threads than 1.  or is the 1.5 meaning it is 1.5 mm between each thread?  or is it the depth of the thread?


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## skiprat (Apr 29, 2009)

Jeff, 12mm x 1.5 mm is a standard coarse metric. A 12mm x 1.0mm would be metric fine and 12mm x 0.75 would be metric extra fine. The feed and pitch of a metric thread are the same. This means that for the 1.5mm tap you have that the depth of the thread is 1.5mm and that there is also a full thread every 1.5mm. :biggrin:


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## Paul in OKC (Apr 30, 2009)

Yep, the smaller the number, the more threads. Go figure. But what do you expect from them over there:biggrin:


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## Darley (May 2, 2009)

Jeff nice try on this pen but don't give up we learn every day and I did today, thanks.

Thanks Skip for the info


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