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BigBoy1
12-05-2014, 09:27 AM
I have designed some wooden toys for the grand kids and I wanted to build them. One of them requires a crankshaft made of wire. (3 view drawing of crankshaft below.) I have tried to bend it by hand but it never comes out straight -- too much crookedness in the supports areas to rotate evenly.

I went to a commercial wire bender just to see if they could help. Their minimum order was $5000!

My next method was going use round and flat brass stock and solder it together as I have no welding ability or equipment. However, that fabrication method to produce the crankshaft will make it very difficult to attache the wooden parts to the shaft. Does anyone have suggestions as to how to bend the wire or another method to fashion the crankshaft?


http://i163.photobucket.com/albums/t308/i422twains/Crankshaft_zps2799551c.jpg (http://s163.photobucket.com/user/i422twains/media/Crankshaft_zps2799551c.jpg.html)

Lew Hartswick
12-05-2014, 09:36 AM
Boy that is a tough one. In three planes with that many throws. GOOD LUCK. :-)
...lew...

iMisspell
12-05-2014, 10:05 AM
Being thats its only 1/8
Could you make a die and toss it in a press ?

Take two pieces of 1/8 plate, mill your male and female templates, then sandwich one of the dies between two more flat plates, insert your wire, then press the other milled die down ?

Maybe im not understanding the whole thing, sorry if so.

_

Black Forest
12-05-2014, 10:23 AM
I have designed some wooden toys for the grand kids and I wanted to build them. One of them requires a crankshaft made of wire. (3 view drawing of crankshaft below.) I have tried to bend it by hand but it never comes out straight -- too much crookedness in the supports areas to rotate evenly.

I went to a commercial wire bender just to see if they could help. Their minimum order was $5000!

My next method was going use round and flat brass stock and solder it together as I have no welding ability or equipment. However, that fabrication method to produce the crankshaft will make it very difficult to attache the wooden parts to the shaft. Does anyone have suggestions as to how to bend the wire or another method to fashion the crankshaft?


http://i163.photobucket.com/albums/t308/i422twains/Crankshaft_zps2799551c.jpg (http://s163.photobucket.com/user/i422twains/media/Crankshaft_zps2799551c.jpg.html)

Damn Designers! Fire the SOB that designed the toy and hire another that will think of the production end of the process. That is why every new hired engineer in my business had to work for one year in the shop before he ever got to touch a computer or CAD program. As in, there is room for a bolt and nut in the assembly but no way to get to the nut to tighten it in the real world.

Edit: Kids shouldn't have toys. Scrooge is your friend this time of year!

Royldean
12-05-2014, 10:33 AM
My only suggestion is to try bending it on one plane, and then twisting the portions into position....

RichR
12-05-2014, 11:27 AM
Hi Bill
Take a piece of 1/2" steel and drill a 1/8" hole lengthwise in your lathe. Face off the end at an angle so you can bend a little past 90 degrees to allow for
springback in the wire. While the compound is still set up, use the cutting bit to scribe 3 lines 120 degrees apart to use as reference marks. Now slit the
piece lengthwise most of the way. Insert your wire and clamp the fixture in a vise so it squeezes shut on the wire. Make your bend, loosen the vise, and
advance the wire to the next location to bend, tighten the vise and repeat.

janvanruth
12-05-2014, 02:31 PM
Hi Bill
Take a piece of 1/2" steel and drill a 1/8" hole lengthwise in your lathe. Face off the end at an angle so you can bend a little past 90 degrees to allow for
springback in the wire. While the compound is still set up, use the cutting bit to scribe 3 lines 120 degrees apart to use as reference marks. Now slit the
piece lengthwise most of the way. Insert your wire and clamp the fixture in a vise so it squeezes shut on the wire. Make your bend, loosen the vise, and
advance the wire to the next location to bend, tighten the vise and repeat.

i like this one

lynnl
12-05-2014, 03:16 PM
Hi Bill
Take a piece of 1/2" steel and drill a 1/8" hole lengthwise in your lathe. Face off the end at an angle so you can bend a little past 90 degrees to allow for
springback in the wire. While the compound is still set up, use the cutting bit to scribe 3 lines 120 degrees apart to use as reference marks. Now slit the
piece lengthwise most of the way. Insert your wire and clamp the fixture in a vise so it squeezes shut on the wire. Make your bend, loosen the vise, and
advance the wire to the next location to bend, tighten the vise and repeat.

Rich, Ref this slit: are you talking about a slit to form a hinge to facilitate squeezing shut? ...or a 1/8" wide slit to permit sliding the wire sideways into the hole? ...or maybe both, i.e. two slits?

In other words, after two bends are made, the wire could no longer be withdrawn from the hole. ....unless I'm not picturing this correctly.

RichR
12-05-2014, 03:58 PM
Hi lynnl
I mean slit it all the way through down most of its length, so it looks kind of like a collet.

boslab
12-05-2014, 11:43 PM
I thought about it for quite some time, bending it, fabricating it from straight wire,straight journals and round flat disks silver sliders together was the closest solution as the throws could be drilled for journal pins, then assembled, excess material on the disks then ground away after the silver soldering to produce the crankshaft, if it was wood I'd probably use brass tube instead of wire as a pair of pins could be drilled into a plate to aid assembly, the disk placed on then the tubes dropped on the pins finished with the next disk, how to stop the solder sticking to the guide pins, use Ali I suppose.
Then I tried imagining how to assemble the whole thing and got a headache, perhaps a design change is needed, instead of a crankshaft would it be practical to use a camshaft instead, bit of brass bar perhaps?
A stack of brass disks with the offset drilled through and threaded onto a shaft, locked in place with a tiny BA grub screw, then adjustments could be made to get the right angular displacement?
Once the original had been set up correctly then it could be removed, a silicone mould made and the cam replicated in low melting point casting alloy
Mark

JRouche
12-06-2014, 12:13 AM
90 degree forming pliers. Keep it simple Bill. To bad yer not Steve. KISS. Keep it simple stupid. :) Umm, enjoyed the thread... JR

browne92
12-06-2014, 09:41 AM
RichR, let me see if I got where you are going with this:

Feed your 1/8 rod through your "collet" with the 1/4" "bearing" surface sticking out, bend. Pull out the rod the 3/4" height of the first lobe, bend. Pull out the rod the 3/4" width of the first lobe, bend. Continue until done.

Am I on the right track?

RichR
12-06-2014, 12:03 PM
Hi browne92
Yes, that is correct. If you mark one side of the rod with a Sharpie, you can use that to keep the rod aligned to one of the reference marks I mentioned
in my original post.