Keyway cutting inthe lathe

[don-tucker]

I want to make a keyway cutting attachment for the ML7,thinking of taking the screw and handle from the end of the top slide and replaceing it with a pivot going downwards ,for a lever attached to the cross slide tee slots,with a slot in the end of the lever.They are only small keyways so not a lot of strain needed,I feel it would be better than racking the saddle back and fore.
What do you Guys think ?
Don
PS Wish i could write like some of you boys on here.

 

[SBWHART]

Hi Don

This is the key way cutter I knocked up it aint pretty but it does the job.

And this is how I made it.

http://madmodder.net/index.php?topic=1859.0

Hope this helps

Stew

 

[don-tucker]

Thats good Stew,I thought ,using the top slide would save making quite a bit.
Don

 

[tel]

The first one I made was like that, but it was a real pain in the a*** removing and replacing the top slide screw. Went to this one quite a few years ago, similar to Stew's but adapted/modified from a published design in the ME press of the day. Of course, since I got the Douglas shaper this one doesn't see much use either.

 

[don-tucker]

The number of times I will be using it,I dont think removing the topslide screw would be to much of an issue.Keep the ideas coming please.
Don

 

[tel]

If I think of it in the morning, I'll dig the other one out and photograph it for you

 

[don-tucker]

This is what I came up with,I try to use what is in the scrap bin now I am not in work with inlimited stock,those were the days ;D

It is very basic ,I used phosphor bronze bearings and whatever else I could find.Works fine without doing ang cutting,I'll let you know.Takes 2 min to change over.
Don

 

[rleete]

I'm guessing it saves cranking a handwheel back and forth. Easier on the human.

 

[don-tucker]

Eureka,it works,admitidly in EN1A mild steel'and here's the proof

I didn't want to put to much strain on the carrige gears and rack and it is easier on me.
Don

 

[tel]

Good one Don, very similar to the original one of mine.

Pat, racking the saddle is OK for one-off keyways etc, but once you start cutting (say) gears or splines at an angle you will soon see the need!

 

[MachineTom]

Not a fan of putting that much force on a lathe carriage. Recently I needed to broach a iron handwheel, and did not have the correct size broach. So a piece of HSS 1/4" was ground.126" wide and using a collet in the bridgeport, locked the brake and using the quill handle shaved a nice keyway in a few minutes. Cuts are each about .005 doc, there was no relief cut on the back of the tool so there was a slight taper in the depth, which was taken into the total depth.

 

[don-tucker]

Thats worth remembering Tom,thanks
Don

 

[steamer]

My version...mounts on my AXA tool post, if you turn the compound you can cut taper keyways

 

[cl350rr]

Newby question: none of these appear to allow the tool to move away from the work on the return stroke like a clapper box on a shaper. Does this dull the tool or am I missing something?

 

[don-tucker]

I think that would be asking to much,for small one offs you can get away with it.I did anyway.
Thats a nice one Steamer.
Don

 

[Blogwitch]

CL,

Unless you are cutting them all the time, it is just as easy to cobble something together to do one or two off's. I just mount a normal ground up tool into a toolholder, with the rearmost grubscrew screwed all the way in and the tool pushed up to it, to take the end force load. Then just use the saddle feed.

There are lots of catskinning ways.

As Don says, you can get away with it, 99.9% of the time.


Bogs

 

[cl350rr]

I tried the lathe caraige method once, was cutting a 1/8 keyway in mild steel about 3 inches along the outside of a shaft and had to sharpen the tool a few times due to taking the edge off. always figured it was because the tool remained in contact with the work on the back stroke.

 

[Blogwitch]

But if it got the job done, 'nuf said.


Bogs

 

[cl350rr]

just looking for a better way, that's all

 

[steamer]

You can pretty much get away with it because the lathe is such a poor platform as a shaper ;D

The depth of cut is at most about .001 per stroke and you end up taking a few strokes per depth adjustment anyway because of the lack of stiffness of the whole system...and I have a good size lathe. ( 12 x 40 Logan)

Once you get above about 1/8" wide keyways,...its laborious, but a whole lot cheaper than a broach set....and because I keep my post square and parallel to the work, it's there ready to go in the time it takes to change a tool as opposed to cobbling up a broach for a one off.

I use HSS drill blanks as cutters, but you need to keep the overhang very small, and use the biggest bar you can on the tool......and you sharpen the tools a lot....

I put some .156 wide x 3/4 deep keyways in my shop made metric change gears and it worked just fine....but it won't win awards for metal removal rate!

The ram on mine is 7/8" diameter, and I think it should have been 1" for rigidity. I may bore the bearings out and make a new ram.....
Dave