Will this ever work? Input appreciated.

[Topsy]

Hello everone,

Yesterday I, once again, took up the experiment of trying to turn a kitless pen.

In the past I have successfully managed to turn sections. You'd think that this would be the hard part, but it seems that I have mistaken.

My lathe bed is very small and drilling on it is virtually impossible, unless I find miniature length drill bits..

At the moment they way I'm attempting the cap & barrel is the following:

I start by shortening the blank my about 1.5cm, for it won't fit at full length with a live center in the tailstock. (Just so you can put the above image into proportion..)
I turn it round in a 4jaw chuck.
On the tailstock end I'll drill a small center hole.

I then take the blank over to my drill press and drill the cap/barrel
holes with a 8mm and 9.25mm (thread) / 7, then 10mm and 11.25 (thread) drill, for the cap respectively.

Then I proceed to cut the inside threads. Lastnight I 'guided' the taps with the drill press' chuck by simply touching the tap, not clamping it, and turning the tap by hand.

Up to here the drill is not moved, so theoretically all the holes & threads should be on the same axis.


I have made threaded 'holders' for the barell/cap that inserts into my collet (, ER16, 10mm, I don't have a larger one currently). With the workpieces mounted to these I'll turn them down to shape and size.

However, latest by cutting the outside thread of the barrel I will mess up.
It's never even remotely straight. But for the 'holders' I appear to have managed..

Problem is, even if I'd have a die holder, I can't insert my workpiece anywhere anymore at this stage and would be forced to turn it down to the outer diametre before drilling.
And assuming that I manage to drill straight (because technically the drilling should be the first step that gives me a 'squared' starting point. I'm reluctant to mix it with something that might end up being off axis), I'd be afraid to turn down the blank to shape with the piece being held by a thread wall that thin.

Does anyone here have any brilliant ideas or should I put this project aside?
I really don't want to do the latter, but I also don't want to go on chasing something that might be impossible either..

I welcome your thoughts!

Topsy

is there a market for banana pens?

note: I turned the cap first.. Way too thin and then turned the barrel thinking I'll make a new cap for it, but since I had both parts I had to try it.

 

[Curly]

Since you are drilling and tapping the inside threads in one operation you should cut the outside threads then too. On Facebook in the Kitless Pen Makers section, Jim Hinze put up a couple videos on making a kitless and he showed a tool to cut short tenons, kind of like a fly cutter for holes, that he runs over the spinning blank. He isn't revealing many details yet but will when he is ready to sell them. You could basically do the same with a small boring head for a milling machine if you could find an adaptor to fit it in your chuck. Or, find plug cutters/ dowel cutters the right size. It would work as well in a drill press to size the tenon. Then you can get a die holder like the ones Victor sells and put a transfer punch in your chuck for the die holder to slide on. Once finished cutting the inside and outside threads you would mount on a mandrel between a live centre and shape the outside. Turn off the very end last. Make sence?

 

[Topsy]

Since you are drilling and tapping the inside threads in one operation you should cut the outside threads then too. On Facebook in the Kitless Pen Makers section, Jim Hinze put up a couple videos on making a kitless and he showed a tool to cut short tenons, kind of like a fly cutter for holes, that he runs over the spinning blank. He isn't revealing many details yet but will when he is ready to sell them. You could basically do the same with a small boring head for a milling machine if you could find an adaptor to fit it in your chuck. Or, find plug cutters/ dowel cutters the right size. It would work as well in a drill press to size the tenon. Then you can get a die holder like the ones Victor sells and put a transfer punch in your chuck for the die holder to slide on. Once finished cutting the inside and outside threads you would mount on a mandrel between a live centre and shape the outside. Turn off the very end last. Make sence?

Forgot to call my 'threaded holders' mandrels by the way :redface:

Thanks for the tip on the facebook group, I don't use facebook much at all anymore and would never have thought that there might be a group there!

What you say makes perfect sense and helped me think out of the box (at least the one I was in!) in a bit.

I'll try to find a solution that would work on my drill press for now.

I just wish my lathe would at least have a morse taper and not a M12 thread.
I found one shop that makes/carries chucks and collets (only up to ER20..) that fit.

 

[Curly]

That particular group only started about a month ago so wouldn't be well known.

There are 3" diameter (76.2mm) chucks that take ER32 collets. You fit a backing plate to them that matches your spindle. Little Machine Shop have some and they have a 1/2" x 20 TPI thread on them. If the chuck isn't too big for your lathe you could ask if they can send you an undrilled backing plate or get a bigger one and have a adapter made for it.

You can make kilts pens on a small wood lathe and it might be better in the long run than trying to adapt what you have. Space and budget not being a restriction of course.

 

[More4dan]

What taper is your tailstock? Little machine shop had tap guides and die holders with a Morse taper so you can tap and thread perfectly straight on the lathe.

I can measure the length of mine once in the tail stock if you need to confirm it all will fit. I use them on my metal lathe with just 8" between centers.

Danny


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[Topsy]

That particular group only started about a month ago so wouldn't be well known.

There are 3" diameter (76.2mm) chucks that take ER32 collets. You fit a backing plate to them that matches your spindle. Little Machine Shop have some and they have a 1/2" x 20 TPI thread on them. If the chuck isn't too big for your lathe you could ask if they can send you an undrilled backing plate or get a bigger one and have a adapter made for it.

You can make kilts pens on a small wood lathe and it might be better in the long run than trying to adapt what you have. Space and budget not being a restriction of course.

Asking them sounds like a plan.. I'll need to measure if it fits but from memory it might be pretty close.

Space is less of an issue than the money. I got this lathe for just 150$ and can't easily stretch to something more expensive as I currently don't have a regular income.
I was however wondering if it makes sense to try and carry on with this limited space.

I once bought extension rails for it but they get a bit flexy and with them installed I can't use the carriage anymore which comes in handy when doing some metal work.

What taper is your tailstock? Little machine shop had tap guides and die holders with a Morse taper so you can tap and thread perfectly straight on the lathe.

I can measure the length of mine once in the tail stock if you need to confirm it all will fit. I use them on my metal lathe with just 8" between centers.

Danny

Thanks a lot for the offer Danny,
sadly my lathe does not have any morse tapers at all, just m12x1 threads on both head and tailstock.

I saw that lathecity would have mt0 head and tailstocks available but I've got some time to think about those. I am currently not in a position to be paying the shipping costs from the US unless I maybe can have things from various shops sent in one parcel.

 

[More4dan]

What is the size of your chuck and what is the maximum diameter that can fit though it? I have a 3" that would only pass 5/8". I discovered it could be safely bored to 3/4". I now turn my blanks to just under 3/4" so I can fully recess the blank into the chuck. Now I have more room to drill on the lathe. Just a thought.

You might be able to use a dieholder in your drill press with a blank vice to hold the pen straight while you thread.

The base usually goes into a taper but the front section that holds the die slides on a rod. You could fit a rod that could chuck into your drill press instead. You could do the same with a collet in the tail stock.

It wouldn't be hard to make one from aluminum bar that could be made shorter if needed.

Danny


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[mredburn]

If thats a Unimat or clone, and it looks like a Unimat, it has a straight short shaft for the tailstock and a 12mm x1 threaded spindle for mounting chucks.

 

[mredburn]

I wont say you cant do it but your pushing the boundaries on what its meant to do.
Small metal bands for details or center bands, nose cones, finials for the caps sure.

 

[Topsy]

I spent some time today just looking at it and thinking. Then I suddenly remembered the other tailstock I have..

The previous owner cut a 12x1.5mm thread right through the 12x1mm thread on the tailstock and it didn't work *that* well anymore, for obvious reasons, so I found myself a replacement on ebay and put the old one into a draw and banished it as "broken" in my head.

I dug it out again today dismantled it and with the old 3jaw chuck, which too has seen better days, made this:
https://www.youtube.com/watch?v=n1QJMw_oy5k&feature=youtu.be
(just for movement-demonstration purposes)

If it's true it should work I think. I can even reassemble the tailstock with a spring in it. The taps & dies fit fine too.

Just need a new 3 jaw for the spindle side or a larger collet chuck.

Regarding that, the largest diametre chuck I can fit would be 70mm..

 

[More4dan]

Can the rear chuck hold your die and use the collet for the pen?


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[Topsy]

yes, that was my thinking today, it should just be possible.