giant pen mandrel advice?

[duckkisser]

ok can someone help me make a giant pen mandrel? What i had thought to do is take a threded rod and put it through the head stock. ill then make three parts to hold it in place.

first a knob to tighten on the far left of the lathe motor on the threded rod.

second a guide to go through on the right hand side to be mounted in my 4 jaw chuck

third a tapered wood guide to be mounted in my tail stock to keep the metal from spining wildly.

figure that way i can keep my rod to stay true while im turning. the rod that im working with is a 3/8 rod. im making jump ropes and need to mount the wood safely so that kids can make them with few issues. i have seen lathes with a drill chuck with a threded rod on the back and a knob that pulls the drill chuck tight and keeps it from coming lose. will this work or might there be a better way to make this work?

[duckkisser]

ok i built it but there is alot of oscilation in the rod......any sugestion folks?

[rmac]

Can you post some pictures of what you did? I didn't quite understand the description in your first post.

-- Russ

[Lawrence Brown]

So what do you mean by a giant pen? Are you using one of the large pens or doing something on your own? If you're using a kit, is there a reason you can't just use the mandrel that's made for it? Mandrels take a bit more work and are fussier to make than you might think.

[duckkisser]

the rod that im working with is a 3/8 rod. im making jump ropes and need to mount the wood safely so that kids can make them with few issues. i have seen lathes with a drill chuck with a threded rod on the back and a knob that pulls the drill chuck tight and keeps it from coming lose. will this work or might there be a better way to make this work?

i have the threaded rod going through my lathe all the way to my tail stock like a pen mandrel(thats why i called it that) im piercing all the way through the wood with a drill bit like a pen blank. ill post some picture of the set up i made and how its hooked up on the lathe. perhaps you guys can give me a idea of what i can do better.

[dwacker]

Use lamp rod with your chuck and live center. Lamp rod is threaded and hollow. We used to use it for vac chucking.

Don

[duckkisser]

ooooooo dwacker that might work.......does it vibrate quite a bit? and i like the idea of using it for a vacume chuck......can you put a photo of your rig on here and posibly i can get some ideas .

[dwacker]

ooooooo dwacker that might work.......does it vibrate quite a bit? and i like the idea of using it for a vacume chuck......can you put a photo of your rig on here and posibly i can get some ideas .

I dont have a lathe anymore. Search diy vacuum chuck on google. Even better go to venner supplies .com look under vacuum clamping, Joe sells a inexpensive kit.

Don

[duckkisser]

here are some photo sadly i had to use my phone as my camera got droped out of my car.

this is what i made

[rmac]

Okay. I see what you did. A couple of questions:

1. Do you have a live center for the tailstock of your lathe?

2. When you said the mandrel was oscillating, can you tell if the rod is bending as it's turning, or if maybe the hole in the guide that's in the chuck is not centered?

3. Is that a 1/4" threaded rod you're using for the mandrel?

4. What kind of lathe (make and model) is that?

-- Russ

[duckkisser]

Okay. I see what you did. A couple of questions:

1. Do you have a live center for the tailstock of your lathe?

2. When you said the mandrel was oscillating, can you tell if the rod is bending as it's turning, or if maybe the hole in the guide that's in the chuck is not centered?

3. Is that a 1/4" threaded rod you're using for the mandrel?

4. What kind of lathe (make and model) is that?

-- Russ

1. yes i do have a live center was trying to make a mandrel saver

2. not sure if its the rod or not but the wood guides have a threaded t nuts so that i can keep the center lined up.

3. using a 3/8 rod because 1/4 was too small for the ropes

4. i have a delta 46-460 midi lathe.

[rmac]

You made some wooden parts with T-nuts in them to set up the 3/8" piece of threaded rod as a mandrel. I'm gonna bet that the holes in these parts aren't perfectly centered, and that's what's causing the vibration. Here's what I would instead:

1. Drill a shallow hole into one end of the threaded rod so that it works nicely with your live center (in the tailstock). Make sure the hole is centered in the end of the threaded rod.

2. If you don't have one already, get a drill chuck with a #2 Morse taper to fit your lathe. You will use it over and over for all kinds of stuff. Here's what I'm talking about:

http://www.pennstate...store/TM32.html

3. Put the drill chuck in the headstock of the lathe.

4. Put the end of the mandrel without the hole in the drill chuck, and support the free end with the live center in the tailstock.

5. Turn on the lathe and see that the mandrel is running true. If it is, instll the blank and turn away! If the mandrel is not running true, inspect your setup in order to find what's wrong, then fix it.

Hope this helps.

-- Russ

[duckkisser]

i tried that with my drill chuck. the only problem was that it did not want to stay in the headtock. the drill chuck kept coming lose on me. then i read somewhere that you can put a threaded rod on the back of a drill chuck and do what i did for my mandrel to keep it secure. my drill chuck is unable to do that. so i came up with the mandrel idea. i might drill a hole in back of mandrel and thread it to make my own threaded chuck. is this a realy bad idea? also whont my live center point get ground down the metal?

any advice on how to get the hole perfectly centered so im not little bit to the right or the left of center?

[dwacker]

Why don't you just turn them between centers. It's easier to knock the point out of your tailstock and drill them with an auger bit while still on the lathe. Just use a regular electric drill.

[duckkisser]

my thinking was that if we drill the hole first then put it on a mandrel the kids could not acidently drill the center hole off center or have it pop through a side because they had the handle at a angle. also we would have no waste block on the ends that would need to be cut off. im thinking ill have to just mount the wood and my drill chuck and move a bit into the turning wood to make a hole was hoping to prevent that as the kids can well be kids and it makes me worry.

[jHop]

Was flipping through some older Popular Mechanics online, and ran across a variable mandrel. Unfortunately, I was moving too fast through the six different tabs, that I forgot which issue it was.

I was doing a Google search, using the terms "popular mechanincs what to make 195", as I was looking for something else specific that (I thought) came from the 1950s. (This mandrel did come from the 50's and 60's issues of _What to make_, but I don't remember which one. But it's a start...)

From what I remember, it was a pair of cone shapes on a central rod. However, you've already got more on the central rod than what I remember... I'll keep looking.

[rmac]

i might drill a hole in back of mandrel and thread it to make my own threaded chuck. is this a realy bad idea?

I don't understand what you're talking about here.

also won't my live center point get ground down by the metal?

I don't think so.

If you taper the hole in the threaded rod to match the point on the live center, there shouldn't be any grinding action because the live center and the mandrel should rotate together on the lathe. (That's what the live center is all about ... it rotates.) Also, the point on the live center should be made out of some kind of hardened steel, and your threaded rod is made from a lot softer material. So with the live center pushing on the mandrel, and the mandrel held by the drill chuck, I don't see how the drill chuck could come out of the headstock.

any advice on how to get the hole perfectly centered so im not little bit to the right or the left of center?

Which hole are you talking about here? The one in the jumprope handle, or one of the holes in your mandrel setup?

-- Russ

PS: Machinists have what they call "center drills", especially made to create the tapered hole that matches the lathe centers. They look like this:

http://www.grizzly.com/products/1-8-Ground-Center-Drill/H4459

[duckkisser]

never mind about the threading of a chuck easer to just buy one and more acurate.

when i was using my drill chuck to turn a short rod i was doing it without a tail stock. so that might make a real difference wish i had thought of that.....sigh duhhh moment

i should have been more clear, but i was talking about the hole in the end of the mandrel if that hole is off wont my whole rod be off?

going to talk to some machinists in the area and see if they can come up with a solution

i had a thought if i had a cone shaped live center and a cone shaped drive center(do they make a cone shaped drive center?) then i can plug the cones into the 3/8 hole turn the project. just need some way to expand/dig into the hole enought so that i can turn the project without it sliding around.

thanks guys i know im making this more difficult then it needs to be but just trying to figure out a way that this is a fool proof method of turning the wood so that with little instruction anyone can make them. thats why the pen's are a perfect starting project. sadly the school wont let us make pens for all the kids since they can be taken apart and used to harm.

[dwacker]

Your lathe is designed to use a hand electric hand drill through the tailstock that's how you drill out lamps. Turn the stock shut off lathe drill two thirds of the way through the center of it and you're done. You drill it right on the lathe between centers. Your tail stock keeps the bit centered. The hole is not just for your knockout bar. The center of your live center should have a knock out point.