Expanding pin/collet chuck

[workinforwood]

On to my next problem. I always need one of these anyhow. I have the Nova chuck on my little jet lathe, but that doesn't fit inside a pen tube of any size. I'm searching and searching, but there's many options available of different chucks doing different things and at different prices. I swear I found what I needed, but it was $500..way too expensive, and I don't even know if that's what I wanted. I want to be able to grab a nib from the inside to spin it to size, and also use the same chuck for other jobs, like to grab a closed end pen from the inside. I'm looking for quality, but also for value, big value, or huge savings value, without having to try and build my own. Suggestions? Thank you !

 

[Scott]

Hi Jeff!

For holding a nib from the inside, I would think that something along the lines of a small pin chuck would be the best choice. Make it yourself out of drill rod of the appropriate size, and maybe a little chunk of wire for the pin. I don't see why it wouldn't work. I hold nibs in my collet chuck, but it does make me nervous to be cutting that close to the face of the collet.

As for something like an expanding collet to use for a closed end pen, what you describe is like the closed-end mandrel that Bill Baumbeck sold. I haven't looked, but I suspect he still does. I have used it and it seems to work just fine. But I've also used pin chucks for this and they work fine as well. I'm kind of a tool fanatic (kind of???), so I like to try the different tools available.

Good luck! I'll look forward to seeing what others have to say.

Scott.

 

[gwilki]

Jeff: Are you turning down a kit nib section to cover it with a sleeve of the pen material? If so, you may want to try threading it into a coupler and holding the coupler in a Beall chuck. It works very well for me. If this isn't what you want to do - never mind.

As for holding a barrel, I just make pin chucks from bolts. They work very well and you can't get much cheaper. You can go with o-ring chucks, too. Same idea, but different.

 

[workinforwood]

I"m building the nib from scratch, already ordered the tap. Also will be building the finial in a similar fashion. Not spinning a closed end pen, but if I had something that can do that and hold a nib too, would be great. The midi Nova chuck just doesn't close small enough to hold a bolt that is small enough to fit in a nib or a pen. I've been using the A-mandrel, pushing the rod deep into the collet piece and it works, but doesn't hold very well.

 

[workinforwood]

http://www.dunhamtool.com/expanding_mandrel.html

This is one I was thinking about if it would work, but I think it's just a hair too big. It says it is 5/16 at it's smallest size, I have to go measure to see if that fits inside a cigar nib hole. It does look also like it might fit in the center safety bolt hole of the Nova chuck. And the price is sure right. Any thoughts on that? Good investment?

 

[ldb2000]

Hi Jeff
Why don't you just make some jam chucks . I use them all the time to hold nibs , grips , boxes , thimbles , rings , heck even whole pens . Just get some scrap wood or do like I did and buy a bunch of birch blanks (I think I paid about $10 for a box of 50 1"x1"x6") , they work great

 

[rherrell]

Get some Delrin or a plastic blank and make a jig. Drill and thread a hole in the end of a 1/2" piece of Delrin to match the threads on your nib. Turn a tenon on your nib piece and thread it. Now put the two together, put it in your chuck and turn your nib to the shape you want. I use this method for all sorts of stuff.:wink:

 

[Daniel]

Jeff, I sort of have a mental picture of what you are trying to do. and this is the solution I thought of first. Turn a piece of metal, really hard wood or whatever, (I have some Iron wood that would work great), Large enough for whatever chuck you use to hold. then turn the very end just large enough to thread for the nib. You said you had a tap but did not know if you are also getting a die. If you do not have a die then you could drill the end of the metal/wood piece and put a rod or bolt (headless in it to hold the nib. I think a one piece jig would give better precision and I have not had the best of luck with the bolt insert in the past with other such jigs. A little JB Weld might solve the problems I have had.

 

[Daniel]

I just looked at the little expanding chuck. It says it is machinable. Does tha mean you could cut the 5/16 one down even smaller if needed?

oops just read the list on the right side. and it does say clearly. "Machinable by customer to desired diameter"

 

[workinforwood]

yes, in the past I made my own jigs for these types of things. Bolts, dowels, rods, tried several things and I can resort to that again, but this expanding chuck is only $30, it will fit into the center of my nova chuck, so there is no monkeying around with centering , and no time consuming jig building or anything else. Just mount it and your off to the races..worth every penny and is re-usable for many jobs of various small sizes. They emailed me back, and I am going to purchase it on Tuesday. It can be milled down to 9/32 which is the size I need. That's only a 32nd smaller than it already is. They said I just have to go real slow, easy and gently milling it down with a file, and not to go much beyond 9/32 for the smallest size. This of course will mean when expanded, the maximum size with be a 32nd smaller as well, but that's ok. You can add that back and more by installing a couple o-rings over the chuck bit. I'm excited..doesn't take much for me I guess. But I just want to keep things cheap and simple, and that's what this is, so I'm patting myself on the back for persistently searching it out!

Rick..is this it CC 410 ? It says 1/2 but machinable to smaller size .250 if I remember right. Will this fit in a 9/32 hole? The price is more, but not that much more and it looks like it screws right on to the head stock maybe? It has the breakdown photo schematic with the adjustment screw in the back. You need a long long allen wrench I bet, lol. Might come with one, I'm sure they have thought of that. Tell me if this looks correct and will fit and I'll email them to verify mounting and how to reach the screw while it's mounted.
http://www.dunhamtool.com/expanding_collet.html

 

[rherrell]

Jeff, I just looked at that expanding collet you're buying and it looks like you have to tighten it from the front which means that anything you put on it will have to have a hole in it big enough for the Allen wrench to fit in. Will your nib have a hole that big?
You won't be able to use it for anything with a closed end.

 

[workinforwood]

Wow Rick! Great catch, good eyes on you! I haven't bought it yet. I will send them another message and inquire about that for sure! I was looking at arizona silhoutte mandrels as well. I sent them a simple message, asking if any of their expanding mandrels would fit in a cigar pen nib so that I could use it to spin nibs as well as closed end pens. They replied, I don't understand what you are talking about. I thought my question was very clear and concise, but I guess not. I dont know how to re-phrase my question.

 

[Daniel]

I was wondering how it tightened my self. The description says it is with a "draw bolt" I also clicked on the expanding collet link where there is a drawing of at least one type of collet and the draw bolt, although small, is at the back end of the chuck. Hope this is true for all of them. I am thinking of one for holding the head stock end of peppermills. But can't decide if i want the MM3 or MM4.
just a thought I had, when you turn down the collet to 9/32 leave a shoulder for your nib to push up against. this will give you good way to make sure the nib is on the collet nice and straight. Just a thought.

 

[KenV]

Jeff-

You are headed into working with machinist precisions and a Nova Chuck is not a machinist choice for holding work with a high precision operation. Machinists tend towards the collet chucks and 4 jaw chucks. Wood working collet chucks tend to have quite a bit of runout (say in the 4 thousands or so) as well as having a lot of back lash. The jaws are not designed for precision either.

Not to say you cannot succeed, but you will have to work harder to get the outcome to tolerances your threads will be looking for.

 

[rherrell]

You're right about the collet, Daniel. It works just like an AS closed end mandrel. The mandrel Jeff wants looks to be just the opposite. Read these directions...

1. Chuck the shank of the expanding mandrel in a collet, jaw chuck, or fixture.
2. With an Allen Key tighten the hex draw bolt until it expands .005.
3. Then machine the slotted member .001 larger than bore of part.
4. Loosen hex draw bolt, position part, tighten draw screw. The part is now chucked and ready for machining.

The first one says to "chuck the shank". If you do that first then it's impossible to get at a screw from the back.
Look into their expanding "collets" Jeff, I think that's what you want.

 

[workinforwood]

Ok, Rick, you are saying to check this same company, but for an expanding collet, not an expanding mandrel? I don't know anything about the greatness of my chuck or run out, but it is a 4 jaw chuck and I can't imagine run out being bad enough to screw up a part as small as a nib. If the nib is .0004 out of round I'll be plenty happy with that!

 

[workinforwood]

Rick..is this it CC 410 ? It says 1/2 but machinable to smaller size .250 if I remember right. Will this fit in a 9/32 hole? The price is more, but not that much more and it looks like it screws right on to the head stock maybe? It has the breakdown photo schematic with the adjustment screw in the back. You need a long long allen wrench I bet, lol. Might come with one, I'm sure they have thought of that. Tell me if this looks correct and will fit and I'll email them to verify mounting and how to reach the screw while it's mounted.
http://www.dunhamtool.com/expanding_collet.html

 

[gwilki]

Jeff: FWIW, looking at the diagram, you would drill your nib section and put it onto the collect. Then you could expand the collect using an allen wrench on the cap screw that is on the other end of the collect.
The only thing that I don't see is how you would then put the expanding collet onto your lathe. Are you thinking of holding it in your scroll chuck? I can't see where they say what the diameter of the collet is, other than the part that will go into your nib section. You would need to find out if your chuck will go small enough to grip it, I guess.

 

[randyrls]

I hold nibs in my collet chuck, but it does make me nervous to be cutting that close to the face of the collet.

Scott; Put a 1/4" fender (large) washer on the mandrel shaft against the collet. You should have collet; washer; bushing; blank. This will keep you from "catching" the collet, and if you hit the washer with the tool, the washer will just spin.....

 

[rherrell]

I think I just found a glitch in our plan.......
Dunham Tool expanding collets may be transferred to any machine using standard 5c collets.
They're made to fit a 5C chuck so they won't work. You want something with a straight shank that will fit in your Nova.
Can you post a photo of what you want to turn? I'm having a bit of trouble visualizing what you're trying to do. There might be a workaround that won't cost you a penny.

 

[workinforwood]

Rick, I'm just making a brand new cigar nib from wood. Exactly the same as one in a kit, but a larger transition to meet the barrel of the pen. There's a multitude of ways I can do it for no cost that I already know. I was hoping though to buy a tool that would do this task and other similar tasks without having to make my own. I don't want to spend alot of money, but if I had a tool like this that can handles several tasks in several similar sizes, I would save myself monkeying around this time and several future times is all.

 

[gwilki]

Jeff: Finally, I get it! Now that I understand what your are trying to do, I can say that I've been there and done that - but for a Perfect Fit, not a cigar.

What I did was take the blank of the nib and drill it out with the size that I wanted for the refill. I think it was a number 37 drill, but it's been a while.

I found a cap screw that was the same size as that hole. I had a piece of 3/4" brass rod, but you could just as easily use a wood dowel. I drilled the end of it and threaded it to take the screw. With wood, you could just drill it with the same bit as you used on the nib and epoxy the screw in. I then cut the head off the screw. Then, I chucked up the brass in my Beall chuck, put the nib blank into the screw, ran a nut onto it to hold the nib blank firm and turned it down. If you don't have a Beall, you could chuck this up in a scroll chuck. Since the "holder" can be as big in diameter as you like, you can use a dowel or whatever that your chuck can grip.

This worked like a charm and I have a jig that will work for any ballpoint pen. The key, of course, it to make sure that whatever you use as a "holder" for the screw is drilled precisely in the centre. I drilled the brass on the lathe, so it was close enough to spot on.