How to make a key way?

[Barnbikes]

How does one cut a key way with out using a broach?

the only way I can think of is drill a hole and file it square.

Is there a easier way?

I have a pile of pulleys and flywheels off various items but none of them are keyed.

Thanks,
Jon

 

[stevehuckss396]

You can grind up a single tooth broach/cutter and use it in the lathe, mill, or shaper. Look on youtube and you will find videos on the subject. In the mill you clamp the part and put the tool in the chuck and scrape a thou or two off at a time by plunging the tool through the part. Same on the lathe but the part is in the chuck and the tool in the tool post. Then you would advance the cross slide to scrape the material out.

 

[MachineTom]

If you have a few to do, I'd suggest EBAY and buy a set, or just pieces. To use a multitooth broach you need a press of some sort, as an 1/8" broach, may need 1000 lbs of force , a 3/8 needs 3000 plus.In addition a 1/8 broach is 5" long, a 3/8 is 11" long. You need to contend with those, as a hammer looks like a good tool to drive the broach, however the teeth are not designed to take hammer blows, and break about 99% of the time.

DuMont is the #1 maker of broaches, their website has loads of info there.

Another way to broach is to ask someone on a site like this to do the work for you. I once needed a piece broached 7/8" in 4130 material, and the keyway needed to be 6" long. Way to big for me, ask the guys on a site, and got it done N/C.

 

[ICEpeter]

Used a hydraulic car jack when I needed to broach a 3/16 keyway. Rigged the car jack in a U -channel / threaded rod frame arrangement and went about it without a problem. Easy to make and use when the jack has a 6 inch plus lift capacity.

Peter J.

 

[bazmak]

You can use an endmil and file out the rad if you wish
If its not too critical then I just go deeper and lock the key with
a grubscrew

 

[stragenmitsuko]

do a google search for "keyway slotter"
There are several designs out there .

I particularly like this one , iirc it was described in one of the projects in metal books .

 

[Philipintexas]

Another alternative to a keyway is a "Dutch" key (Or something like that) which is a bolt hole drilled parallel to the axle axis, half in the shaft and half in the flywheel. Thread the hole and insert a bolt. This requires that the end of the shaft be flush with the face of the wheel-hub so it may not be an answer.
I used this on a 10" cast-iron flywheel on a 1/2" shaft of an IC engine. The inertia of the large flywheel would loosen the keyway in minutes. The bolt has held forever. If you go that route, lock-tight the wheel on the shaft so neither part moves until the hole is threaded. This is an effective method but can be a little difficult to replace as each part must go back in the exact location as when it was threaded.

I've used a boring bar with a custom ground cutter and the part in the lathe chuck with the key-way at the 3:00 0r 9:00 position so the cross-slide will advance the cutter. Set the gears on low so the chuck doesn't move and run the carriage in & out multiple times. Crude and slow, but it can be done.

 

[vederstein]

I've tried in the past (with limited success) of creating internal keyways via clamping a cutoff tool sideways and scraping the bore.