Need to broach a longer keyway

[great white]

I did this one on my lathe, it's only about 1.5'' deep x 22mm dia, but if the bar was longer it could have been any depth. Just grind up a key width HSS bit. Cross drill a bit sized hole in the end of a bar that will fit the bore, and secure the bit with a grub screw. Set up in the lathe and and you too can become a shaper.

Takes a few minutes to do, but is easy

View attachment 283023

Now that looks workable for me! I’ll have to have a rumage through my steel pile to see what I can find...

 

[P. Waller]

My least favorite machine in a shop, a keyseater.
Old, crude and tedious to set up but will do what you require. This is a 3/4" X 4" keyway.
Simply a shaper for internal keyways, brutal but they work a charm.
They also have an adorable Steampunk feed mechanism.

 

[great white]

Well, must be my lucky day.

No 5/8 stock in the shop, but I've got a nice long piece of 1/2 cold rolled round. my AXA holders would need a 5/8 flatted down to fit anyways, so the 1/2" will work for this task with just a skim to flatten the sides.

Then I pulled out a box of scrap HSS pieces I keep around because, well, you never know. I fish around in the pieces and pull out a clean stub of HSS that is EXACTLY the size of the keyway in the transmission input shaft.

A quick dig through my loose fasteners and I turn up a coupe set scres of the right size.

So tomorrow, it's just a matter of building a keyway tool for the lathe and give 'er a try (on a scrap piece first of course!).

 

[great white]

After a totally frustrating and wasted day, I chucked the steel I had for the broach out the door.

Seems the block I was going to use had a broken off drill bit in it. After trying to punch, drill and other wise remove it from the face of this earth, I gave up and fired it in the trash pile. Being xmas eve, it was that piece of steel or nothing. I figured that was it until Well after xmas day as most places around here where I can get a block of steel 1” or bigger are pretty much closed up until january.

Got up this morning and in one last attempt a saving the project, I found an old 1 1/4 receiver hitch tongue in the back of the garage. I chopped it up and it machines like a dream. Some kind of mild steel, carbide tools glide right through it and leave a nice finish.

So after half a day of dinking in the garage, I have the cross slide 5/8” holder and the 5/8” cold rolled bar built.

Now to move on to making the rest of the broach/shaper attachment...,after the turkey dinner settles and I can move again that is!

 

[great white]

Certainly not finished, but here's the "mostly completed" keyway cutter I'm building:

It's got a 4.5" stroke at the cutter position and has a .003" runout at the full length of the stroke. Pretty good for my first attempt at making a "shaper". I'm thinking of adding a gib screw a the front and back to take up even more of that .003". But it's certainly usable for my purposes as it sits.

Next is to mount the cutting tool at the end, make some spacers to replace the washer stacks you can see in teh linkages and some misc finishing up work. Eventually, I'll turn a handle for the end of the lever bar.Just to clean it up if nothing else.

 

[FOMOGO]

Nice job on the broach/shaper. Looks like it should work well. Mike

 

[great white]

Well, it's cutting:





But maaaaannnn.....is it ever slooooowwwwwwww. And it hooks and hangs a lot as well. The "dents" you see on the end of the turning are there because every time it would grab it would rack the turning, so I'd reseat it with a little bumping from the hammer. I eventually dismounted it, turned the jaws of the 4 jaw around and used the curved sections to hold the turning. That seemed to solve the racking problem. Probably should make myself a brass hammer too.....

I had to go though a couple grinding sessions until I got the cutting tooth right. Very fussy to get the geometry just right so it would it cut the 1018 well.

I had to rework the "nose" of the bar a couple times to get as much depth as I could out of the blind hole. I also had to drill a hole in from the side to give the chips a place to break off. That was a fun task. One drill bit broke off and I had to abandon it in the hole, a second hole I messed up my measurement and it was too far up the bore, the third was in just the right spot. I'm not too worried about the couple extra holes, they're under the press fit hub once it's all assembled and the turning is so thick, a couple 3/16 holes are not to going to hurt anything except my OCD.

I had several problems with the tool turning in it's mount, which caused most of the grabbing problems. I finally figured out it was actually the tool post turning in the compound rest. With the amount of force on the tool post, there was just no way to keep it from "creeping" as I worked the slotter. So I changed to the Atlas milling attachment, mounted the slotting tool in the mill vice and that solved the rotating problem. Side bonus is it also allows me to set the height precisely.

But I think it's going to take me 6 weeks to cut the keyway! LOL! Probably would go much better if I was cutting aluminum instead of 1018.....