cutting key ways

[lotus 30]

I am having a go at making the front prop drive for a climax engine what is the best way to cut the key ways in one of these. i am making a trial one now i have a milling machine and lathe. I am only a good amateur on the machines but willing to have a go. I have one to cut as picture there is also one where it slides onto the crank nose

 

[MattF]

The lathe way, (slow but works), is literally the same setup as a boring bar with a correctly profiled cutter, and then just advance the saddle to cut and keep winding back the cross slide slightly before each cut until the required depth way is achieved.

 

[ronan]

Or make up the part without the keyway and bring it to a workshop that has broaches and a press and let them do it. Also one of those jobs a shaper can do well.

 

[lchris21]

several ways........

as stated use the saddle of the lathe?
use your mill and mount a suitable tool in the spindle then up and down with the knee.

or buy this and have lovely tool to keep in the man cave for a future project
http://www.mig-welding.co.uk/forum/threads/hand-operated-bench-shaper.57376/#post-696030

 

[lchris21]

here you go....

 

[lotus 30]

This is going to take some time if i do more i think i will give it to someone better equipped but this first one i need to do for my own satisfaction
Thank you for all the prompt reply's
andy

 

[ronan]

If you could knock up something like in the picture below, and are able to lock the chuck of your lathe, it shouldn't be that difficult.

 

[mike os]

depends on the size, you could use a small endmill and round the corners off the key or file the corners on the keyway

best way is with a proper broach

 

[Maker]

I would turn a tube to a little smaller than the required ID but with the same wall thickness as the depth of the key way and mill right through it from the outside, then turn the part you need and bore it out to the OD of the first tube, slide it in, weld it in place and then bore it to the final dimension. Or, machine it all to it's final dimensions, mill tight through from the outside and make a little piece to weld in the gap. (If that makes any sense?).

 

[awemawson]

You'd not be able to transmit much torque with that method Maker, as the major contact area of your sleeve and the bore cannot be welded, only the ends where they emerge into fresh air.

You could however do something similar, but instead of welding, use a good grade of silver solder, or even braze, that, given suitable flux, would penetrate and be sucked into the joint by capillary action.

 

[lotus 30]

If you could knock up something like in the picture below, and are able to lock the chuck of your lathe, it shouldn't be that difficult.

Funnily enough i cannot lock the chuck unless i make some way of holding it locked the slowest speed is 90rpm so quite steady what do you think. the foot brake is not working either.

 

[lotus 30]

depends on the size, you could use a small endmill and round the corners off the key or file the corners on the keyway

best way is with a proper broach

What does a broach look like how does it work?

 

[Maker]

You'd not be able to transmit much torque with that method Maker, as the major contact area of your sleeve and the bore cannot be welded, only the ends where they emerge into fresh air.

You could however do something similar, but instead of welding, use a good grade of silver solder, or even braze, that, given suitable flux, would penetrate and be sucked into the joint by capillary action.

Or drill it and put in a roll pin.

 

[Newlands]

What does a broach look like how does it work?

http://www.rdgtools.co.uk/cgi-bin/s...-Speed-Steel--with-shim-C-6447384.html#SID=56
You'd also need a press of some sort to push it through.

 

[ronan]

 

[awemawson]

In my experience broaching keyways on a lathe, once a cut has started and is only a few thou deep the engaged cutter will adequately locate the mainshaft from turning. I've cut splines in gears this way before now.

 

[optima21]

last time I needed to cut a keyway was 4mm wide in a 14mm diameter bore, so I used this cutter/holder.the cutter was ground from 4mm square hss and held in place with an grub screw. I used it in a milling machine using the quill to make the cut. I would have used it in the tool post of my lathe, but it was quicker to cut using the quill on the mill. I would have used a larger diameter holder to prevent flexing, but it at this size it would only just fit in the bore

 

[Newlands]

It's easy to lock the lathe spindle - clamp a spanner on one of the nuts under the headstock cover, or a couple of machinist jacks from the bed to the chuck jaws. Just remember not to switch it on until it's unlocked.....

 

[lotus 30]

Or drill it and put in a roll pin.

crank is already got a key way for it to drive the prop

 

[Sidewinder]

I am having a go at making the front prop drive for a climax engine what is the best way to cut the key ways in one of these. i am making a trial one now i have a milling machine and lathe. I am only a good amateur on the machines but willing to have a go. I have one to cut as picture there is also one where it slides onto the crank noseView attachment 71406

Shame you are so far away, I have quite a few broaches, sleeves, and a broaching press!
It takes minutes in a press with a broach.