Kitless help

[FGarbrecht]

I am following Fred Brunings tutorial "How to make a 'kitless' pen", and am having some problems. I cast some 3/4" round alumilite blanks to practice on, drilled the centers with a center drill and turned them down to about 18 mm between centers. I mounted the larger blank (the barrel) in a collett chuck and turned a 1 cm tenon to a diameter of 12 mm. I then cut a thread on the tenon on the lathe with a 12 mm x 0.75 die mounted on a die holder. So far so good. I then placed a threaded delrin collar on the newly cut thread to stabilize it. I drilled out the center with a 7 mm bit to a depth of about 3 inches (that went fine), then came back with a bit sized for my section thread (9 mm x .75 tap). (It's a 'P' bit, a little over 8.2 mm diameter), and the tenon fragmented immediately. Tried again, recut a tenon and threaded it, and tried drilling again, same result. Not sure how to do this now. In the tutorial he cuts an even larger internal thread (10 mm) so there is even less wall thickness to work with.

Any suggestions?

 

[mredburn]

Have you measured your drill bit diameter with a digital caliper?I find they run small, My "P" drill bit measures 8.11. my 21.64th measures 8.24 and my Q drill bid measures 8.34. Taps and dies especially the cheaper ones do not cut the threads 100% of stated depth. I tend to cut my tenons down about .1-.2mm smaller than stated and drill my holes about .1 larger than stated. Hence I would use a Q drillbit.

 

[Dalecamino]

Usually PR shatters as you put it. Whereas Alumilite is the opposite. What kind of lubrication are you using?
I can't tell you what is wrong with your blanks, but I agree with what Mike said. More Good Luck!

 

[FGarbrecht]

Usually PR shatters as you put it. Whereas Alumilite is the opposite. What kind of lubrication are you using?
I can't tell you what is wrong with your blanks, but I agree with what Mike said. More Good Luck!

I used a can of spray silicone. Maybe I should try something more conventional, like PAM in a can. Sorry to be dumb, but what is PR?

 

[FGarbrecht]

Was just checking lathe alignment and runout. The headstock and tailstock appear perfectly aligned on the Z-axis but the tailstock center is maybe .01-.015" back from the headstock center in the Y-axis. (Runout on live and dead centers is <0.001"). Would that be enough to cause my problem? Anyone know how to align a jet minilathe tailstock? I don't see anything on the lathe that looks adjustable, and a quick google doesn't bring much up.

 

[Dalecamino]

Sorry, PR is Polyester Resin. It tends to be brittle, especially the home cast stuff. I use Pam because it's what I have. Some use Mineral Oil, while others have come up with other stuff that I don't recall at this time, and likely never will. Don't feel dumb for asking. And, always keep in mind, that we ALL had to learn about this. Even the first guy who thought of making his own pens. I'm sure he a few had bumps along the way.

Can't help you with the run out.

 

[FGarbrecht]

I spent some time cleaning the tailstock, there was some caked on hard stuff/grease and dried paint on and about the sliding tenons. After cleaning and regreasing I checked alignment and it is much better. If I am careful with how I position a drill bit in the Jacobs chuck I can make the alignment near perfect. Will try the barrel tenon threading and drilling experiment again tomorrow. Third times a charm, eh?

 

[darrin1200]

My normal order of work, is to drill all interior dimensions. Then tap the interior thead.
I then cut the ten into size followed by cutting the exterior thread.

 

[MikeinSC]

Nm

 

[Curly]

Not quite related to your issues but consider keeping silicone sprays and products containing it (Pledge spray wax for example) out of your shop if you ever think you will use any kind of hard finishes like lacquer et cetera on your work. It causes all kinds of finishing application problems like fisheyes.

 

[More4dan]

Measure your hole after drilling, as others have said, sounds like the hole is too small causing the tap to wedge in and crack the blank. I'd use a 21/64" bit giving you a 8.33mm hole. I'd treat this as the minimum hole size. Typically we shoot for 75% thread engagement. This would be 75% of 0.75mm the pitch. This would be the difference in the ID of your hole and the OD of the thread of your front section. There is room to oversized your hole but under sizing doesn't work. You need a minimum 8.25mm hole. The P won't get you there. Practice on some cut offs. I've also found if my tendon is too large, the die will shear off the threads. I make mine slightly smaller than the nominal thread size.

Remember to stay within the 75% of your thread pitch for the difference in the slightly undersized section tendon and the slightly oversized hole in the body. Easier to use in metric than threads per inch in the English system.

Danny


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[FGarbrecht]

Thanks all. After truing up the lathe and reversing the order of threading things (doing the internal thread first, then cutting the tenon and external thread) I was able to get a rough cap and barrel that thread together nicely. I just got a couple of Bock sections and the appropriate tap, and threaded the barrel to accept the section, and that worked fine too. The Bock tap was from Beaufort and unfortunately didn't have an end-hole drilled in it so I couldn't use my tap holder, so it was a bit of a PITA to thread it squarely (I ended up using my Jacobs chuck in the tailstock to hold the tap).

Good point about the silicone spray. I'm about to play with some urushi finishing so I guess I'll need to raid the kitchen for some vegetable oil spray. I'm sure my wife won't miss it, although she has been persistently complaining about how all the scissors seem to end up in the basement.

 

[bmachin]

I might be wrong here, but I think think that Bock sections are metal. A word to the wise: People who really like fountain pens generally really dislike metal sections.

Bill

 

[FGarbrecht]

I might be wrong here, but I think think that Bock sections are metal. A word to the wise: People who really like fountain pens generally really dislike metal sections.

Bill

I bought a couple of the Bock sections as part of my learning process; I wasn't entirely sure (even after reading extensively here) how they were put together, so I needed to get my hands on one to learn how to make my own that would fit Bock nib housings.

Bock does have metal sections but the ones I bought are not metal, not sure what they are, probably plastic. Interestingly the internal housing thread is some kind of threaded insert.

 

[More4dan]

Bock sells their nibs several ways. The feed is plastic but they do sell a triple assembly that includes a metal front section with the plastic feed installed.


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[More4dan]

Thanks all. After truing up the lathe and reversing the order of threading things (doing the internal thread first, then cutting the tenon and external thread) I was able to get a rough cap and barrel that thread together nicely. I just got a couple of Bock sections and the appropriate tap, and threaded the barrel to accept the section, and that worked fine too. The Bock tap was from Beaufort and unfortunately didn't have an end-hole drilled in it so I couldn't use my tap holder, so it was a bit of a PITA to thread it squarely (I ended up using my Jacobs chuck in the tailstock to hold the tap).

Good point about the silicone spray. I'm about to play with some urushi finishing so I guess I'll need to raid the kitchen for some vegetable oil spray. I'm sure my wife won't miss it, although she has been persistently complaining about how all the scissors seem to end up in the basement.

Check your tap holder, on mine the tip is reversible to work with the taps that go to a point. The reversed end has a small cup. The tip is removed by backing out the Allen screw from the taper end and reversing it.

Danny


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[More4dan]

Check your tap holder, on mine the tip is reversible to work with the taps that go to a point. The reversed end has a small cup. The tip is removed by backing out the Allen screw from the taper end and reversing it.

Danny


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I just used my Fountain Pen taps I got in a group buy and yep no way to use a guide. I tried drilling with a center bit but didn't even scratch it. I'll have to get a carbide center drill.


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[darrin1200]

I use a tap holder like this. It has a small hole in the back end to fit my spring loaded center. Works great.

 

[FGarbrecht]

I use a tap holder like this. It has a small hole in the back end to fit my spring loaded center. Works great.


View attachment 226286

Do you remember where you purchased this?

 

[More4dan]

Here is what I am thinking to use for holding taps on the lathe. I have a set of ER32 collets already. I will modify it to slide on the MT2 guide that works on my die holder. So I can hold any tap and thread just like I do with dies. I won't have to keep advancing the tail stock while treading deep and it should be more accurate. Only $20 with free shipping.

I might have to add a sleeve to match the diameter of the die holder slide.

Danny


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[darrin1200]

Do you remember where you purchased this?

I bought mine at Canadian Tire, here in Canada. But I quickly found this one on amazon.com

https://www.amazon.com/Rocaris-Adju...992&sprefix=Tap+holder+ratchet,aps,310&sr=8-2