Cutting a key way in a pulley bushing ...

[FOMOGO]

I have a pulley bushing I need to take from 7/8 to 1 1/8". No problem boring it to size, but I don't have any broaches to do the keyway. Is there another method to get it done? If not, any suggestions for a reasonably priced set? Thanks, Mike

 

[markba633csi]

I think it can be done in a lathe if you can manage to immobilise the headstock; you run the carriage in and out while cranking the cross slide in increments- tedious but doable with a sharp tool
You could also cut it with an endmill side and fill the rounded portion with epoxy, or epoxy the key in to the slot at the same time as the filling
Maybe a combination of endmill to start and lathe slotting to finish? That's a large bore so you'd have plenty of room

 

[Illinoyance]

Use a boring bar in the lathe. Grind the bit to the correct width. Use the carriage to shove the bar through the bore, taking a thou or two each pass. You can also use a vertical mill like a slotter.

If you have a vertical mill you can plunge an endmill through the bore to establish the correct width and depth of the keyway. Finish with a file.

 

[north1]

I believe Tubalcain has a tutorial on doing this in a lathe.

 

[benmychree]

I'd use no larger than a 3/16" wide key, I think that is the standard for that bore size, it still gets fairly thin where the key is, you could make the keyway a bit shallow in the hub bushing. Cutting the keyway in the lathe is probably your best bet. Getting the keyway square with the center takes a fair amount of care to be accurately centered. Best to lay out the centers and width/depth of the keyway on the parts.

 

[Winegrower]

You can look on eBay and find the right size individual Dumont broaches and bushings, won't be too much. I happened to get a whole set, maybe 9 broaches and bushings for less than $100 as I recall.

You would need an arbor press for this, as well.

 

[Ulma Doctor]

Hi FOMOGO,
i took my chances a few times and purchased used Dumont Broaches on the site who's name sounds like E-Pay
i have been lucky, maybe you will be too

all industrial supply has import sets that aren't too bad on the pocketbook.
i can't speak for the quality, as i have not actually used an import broach

 

[f350ca]

Great excuse to by a shaper.

Greg

 

[mmcmdl]

Hey Mike . I made up a clamp for the BP quill that I could broach keyways before I got my broach sets and arbor press . Same concept as using your lathe but a little easier .

 

[FOMOGO]

Thanks for all the input guys. Made an offer on a used US made set on e-pay. Have the bushing set up on the mill now and will bore it tomorrow. Will give the end mill and file idea a try for the key way. Cheers, Mike