making a twister...

[Aaron J. Cergol]

Hi all,

after twisting over 300 1/2" pickets yesterday by hand, I would like to make a twister. that being said. I like to keep my shop as "primitive" as possible so I'd like one that is hand cranked. Now I've seen some nice ones online with four long handles and a bed with a "tailstock" and I like this design, but I'm looking to twist larger stock cold...

So I'm thinking about buying a gear reducer. I have found lots of 30:1 however that would take far too long to do by hand, so I'm thinking 12:1 is a better choice, and could be hooked up to power and timed if necessary. however, that still would seem to take a while if I'm doing a run of them. Maybe this is a stupid question, but would it be feasible to use a 12:1 or greater reducer, and then increase the gear ratio on the handle, so in theory it would be a 1:1 ratio overall, but with two reducers? or is that completely eliminating any reducing advantage that you had hoped to achieve in the first place. Something tells me it wouldn't work, but a small bit in me says that it might be crazy enough to work.

Also can you guys think of any way to set a "stop" or a timed system to do even turns if I want to crank out a lot with a motor? I know there is stepper motors and all that, but is there an easier way? Lastly, will a reducer mean it won't take as much torque (or physical work for me) to turn, or will it be the same amount of work, but seem like less due to it taking smaller bites (turns) out of the piece...

I am thinking a 4 jaw chuck would not hold it well enough, so I'm thinking of broaching several "chucks" to have square holes of different sizes that would be held in place by the reducing shaft.

Thanks for your input, and I apologize if these questions seem stupid. I just can't seem to grasp the overall concept of this.

Aaron

[SmoothBore]

I would think a power pipe threader might put out sufficient torque, at a very manageable speed.


A simple, easy to make, "square to round" adapter, can be made by splitting a piece of round bar lengthwise, and then milling a "V" groove in each half.

This will allow you to chuck the square stock in the 3 jaw pipe threader, ... and one adapter could easily accommodate several sizes of square stock.

Welding a lug on the O. D. of one half of the adapter, will give you a positive drive "dog", ... so that you don't have to worry about the adapter slipping in the chuck. ( Obviously, this would work with a 4 jaw, as well. )


Slipping a loose fitting length of pipe over the square stock, before twisting, should help to keep it straight.


A vise might work better than a "tailstock", to hold the static end of the bar.

[thingmaker3]

so in theory it would be a 1:1 ratio overall, but with two reducers? or is that completely eliminating any reducing advantage that you had hoped to achieve in the first place. Something tells me it wouldn't work,

A complicated 1:1 gear ratio would be a little worse than just going without gears. A bit of energy is lost in the gears (turned into heat and noise).

Also can you guys think of any way to set a "stop" or a timed system to do even turns if I want to crank out a lot with a motor?

Add some more gears and something to turn the switch off?

Lastly, will a reducer mean it won't take as much torque (or physical work for me) to turn, or will it be the same amount of work, but seem like less due to it taking smaller bites (turns) out of the piece...

You do the same amount of work, but over a longer period of time. You therefore exert less force and power.

I am thinking a 4 jaw chuck would not hold it well enough, so I'm thinking of broaching several "chucks" to have square holes of different sizes that would be held in place by the reducing shaft.

Four jaw chucks hold pretty well, depending on the individual chuck. They're basically a fancy vice.

I hope your project turns out well. It certainly sounds interesting. You might also want to search for the twister Ric Furrer made. Others here have posted about self made twisters as well.

[Chrispy]

Aaron,
Sounds like a "Record 360 Pipe Threader" is the sort of thing you are after. Do a search on the net and include the words twister. There is something there that I read about 12 mths ago. The site showed a pair of modified stilsons for the vice end but pretty crude. I ended up getting a second hand commercial twister for AU $400. Its a ruduction gear on a 5 hp electric motor .It works great, I have jigs that go from 3/8" progressively to 1 1/4". Used the 32 mm jig last week on solid steel(cold) did 4 turns easily. Tore through on a piece a foot long but ok for 4 turns over a metre.
Key thing to keep your twists straight is the accuracy of the centres at each end. Out a fraction and it will produce spirals over the twisted length.
Chris

[Old N Rusty]

I use an old RIGID pipe threading machine. it will twist a whole twenty foot piece of 1/2" square bar fast. I made a mark on the chuck and count twenty revolutions that seems to be the best number, to many and the bar starts to twist into a corkscrew.It will twist bars right or left .

[Fosterob]

I have seen several guys who have used an old granny low truck transmission for twisting. Shift gears to get more reduction for larger stock. It will keep your space looking "primative" also. Put your handcrank setup on the input and adapt the output to your square sizes.
Rob

[Aaron J. Cergol]

thanks for the quick replies all.

"A complicated 1:1 gear ratio would be a little worse than just going without gears. A bit of energy is lost in the gears (turned into heat and noise)."
I had figured as much, but still couldn't quite grasp the idea. Thanks.

When I was twisting them by hand, putting a 3/4" pipe around them helped take any warrble out of them immensely. I would think that a machine would keep it pretty straight by itself, but if I see that it's not, I had thought about using two pieces of angle iron for the "pipe". have the two pieces together to make a square; one being stationary, and one hinged and on pivots. This would allow for you to open/close it easily, and I could have a simple locking "slide" on it to adjust for width of the piece. However I do not think that it would be needed.

I do have an ancient Oster pipe threader that came off an old battleship, I had considered using it, however I use it as a pipe threader, and manual tapper, and simply do not have enough room for it in my current (very small) shop. This being said, I'd be looking to twist stuff 10' and under. Heck for the time being, I may either have a clamp on unit that clamps to heavy steel work table, or even something that sits vertical in a corner due to space.

I think I'm going to do some drawing of this and a little more tinkering with design and then I'll try and post my final concept.

Thanks,

Aaron

[macbruce]

Aaron, how large of stock do you ultimately want to twist?

[arftist]

The oster is the way to go for up to 3/4" or so.
You don't need a pipe if the centers are lined up well, as mentioned above. A pipe is Very helpful when twisting cold by hand.
If your pipe threader has a 3 jaw chuck, make collets out of 2" round stock for each size you want to twist. I have 7/16, 1/2, 5/8 3/4
Put a chunk of 2" round bar, 2" long in the lathe, drill a hole the size of the bar to be twisted.
mount in mill, and mil out till the hole is squared up. This will give a good center. the bar is just dropped in, doesn't need to be held.
A pipe vice or a machinist vice holds the other end fine.

[macbruce]

held.
A pipe vice or a machinist vice holds the other end fine.

A word of caution here.......Don't use a cheap piece of...... vice here. I've had em break doing this and the least of your worries is buying a new vice..... ;)

[Old N Rusty]

Arftist metioned the OTHER END, I forgot it. I use a rigid chain pipe vise, mounted on a table that puts it at the center, or close to .the pipe threader machine you get set up and many interesting things can be twisted. For example weld the ends of two 1/4" round bars and twist them tight into a ROPE. Twist two right and two left, then you can forge weld 4 of these pieces of rope together to make a "basket weave" handle for fireplace tools. 1"x1" x 1/8" angle iron twists up into a nice looking piece too. You wont have much luck twisting one piece of round bar, but there are many things that do twist nicely.

[ThomasPowers]

As for automating the count for twisting. I have an old timer that's electromechanical, you wind the indicator to the amount of time you want and then it has two sets of contacts one for things that are on till the timer clicks off and one for things that are off until the timer clickers off.

Hook the motor up to the "on" but with a switch inline as well. Set the time, flip the switch and it will run the set time equaling a set number of turns and turn off. (If you really want to get fancy you could hook up a signal to the other set so it will let you know when it's time to load another as well)

You really don't want to do fence pickets manually unless you hire grunt labour to do it!

Most folks twist long lengths and then chop to size---more efficient.

[macbruce]

Well this is my version of a twister.........3hp hydraulic motor (superior to elec in this app) 50 to 1 reducer, 10' bed,12,000+foot lbs torque, 40 rpm fast/ (shown in pic #1 with the large cog on the bottom) or 11 rpm slow or high torque, accomplished by swapping the cogs, pass through headstock, 1 1/2'' sq cap. cold, not sure how big hot but at least 3''
I've found it to be a good format for a twister and it could easily be scaled down......mb