Enlarging a pulley keyway?

[brewdexta]

I'm putting this 17mm ID pulley onto a new motor that has a 19mm shaft. Some of the keyway will disappear when I bore it out and the new shaft's key looks a tad bigger.

Any tips on how to enlarge the remaining keyway without having the specific head for the mill for cutting keyways?

Cheers
Andy

 

[Hood]

A broach is the normal way, not cheap though for a decent one. If it will be used only occasionally then one of the cheaper imports may not be too bad.

 

[Shox Dr]

Grind a bit of hss up, stick it in the lathe, and use the topslide to shave it

 

[brewdexta]

Cheers guys

I shall try the topslide first as it is hopefully a one off......

 

[optima21]

if its an aluminium pulley, this is the cutter that I used on a milling machine. the keyway was 4mm wide for scale. I just used the quill and advanced the depth of cut to take a shave a 0.05mm thick each time.

 

[ronan]

What about marking it out on the ends and filing it ? The humble file can remove plenty of metal quick, and if you are careful, its very accurate.

 

[brewdexta]

Great ideas guys.

Filing is my last resort, but certainly doable.

 

[slim_boy_fat]

Didn't @doubleboost post a video using an HSS one in the toolpost?

I linked to some in another thread, but they might both(?) have come from the interweb......

 

[doubleboost]

Didn't @doubleboost post a video using an HSS one in the toolpost?

I linked to some in another thread, but they might both(?) have come from the interweb......

 

[8ob]

You are only going to lose 1mm of key, I would shave a mm of the key and run as is.

Bob

 

[slim_boy_fat]

@doubleboost Thanks John,proves I've not lost my memory [completely ]

 

[Shox Dr]

You are only going to lose 1mm of key, I would shave a mm of the key and run as is.

Bob

That’s all well and good lad, but when the pulley has worn out. He’ll have to buy a new key as well. And thems not cheap

Annnnnd no doubt have to buy a gret box full, as they dont sell them out the box any more

 

[brightspark]

You are only going to lose 1mm of key, I would shave a mm of the key and run as is.

Bob

would do the same here keep it simple . the proper way you used to cut keyways was with the correct size small cold chisel cut down either side with a hacksaw and chisel the rest out I did one on a chain gear pulley then finished with a square file

 

[knighty]

That’s all well and good lad, but when the pulley has worn out. He’ll have to buy a new key as well. And thems not cheap
Annnnnd no doubt have to buy a gret box full, as they dont sell them out the box any more

I bought some key way steel a couple of months back, it was pretty cheap, bought 2 bits, 16mm and 18mm because I didn't know which I needed, 400mm long was under £20 for them both

can't remember the name of the place I got them from, proper supply place tho, I paid over the phone and they delivered straight to the engineering place I had machining a shaft for me (they'd run out of that size, don;t normally stock it)

when I picked up the shaft I told them to keep the left over keyway in case they needed it


meant to buy myself some but forgot all about it till just now!

 

[ronan]

Bearing factors sell key steel in short bits. Was in one a few weeks ago and they had all sizes on the shelf in 200mm lengths.

 

[brewdexta]

I did buy some key steel in various sizes but that was ages ago and it would probably take me a week to find 'em. Fortunately the new motor comes with the key

 

[ronan]

I used to have to file up keys in my old job, the steel was dead soft, an easy job.

 

[brewdexta]

Not much of the keyway left after reaming out to 19mm

I shall now choose my weapon to cut the keyway. Well after the gardening and that bit of fencing.....

 

[8ob]

Not much of the keyway left after reaming out to 19mm

View attachment 139259

I shall now choose my weapon to cut the keyway. Well after the gardening and that bit of fencing.....

Reamed or turned? If it was reamed I think the bore center may have walked towards the keyway, looking at the original bore I would have thought you would have had at least 2mm of keyway left. may pay to mount it on a motor and spin it up before going much further.

Bob

 

[brewdexta]

You may be right there, never thought of that, I was just about to stick it on the motor but it has one of those captive keys and they can be PITA to get out.