milling a keyway (talk to me like I'm an idiot)

[premmington]

Exactly why I haven't done any yet

I have always struggled with "broaching" internal keyways in pulleys on repair jobs.

What is my other option?

 

[MattF]

What is my other option?

Get someone else to do it for you.

 

[Brad93]

I have always struggled with "broaching" internal keyways in pulleys on repair jobs.

What is my other option?

A slotter

 

[Brad93]

I would love to see your faces if you knew what I sometimes use to drive a broach

Mill spindle?

 

[8ob]

I need to mill a keyway into a shaft, I've got a bridgeport, haven't used it yet

1 1/2 inch shaft (about 1.5ft long)

keyway in the taper lock bushes is 3/8 x 3/16 (so 3/8wide 3/16 deep?)

so I'll need a 3/8 end mill? something to hold it?

I use end mills to cut keys but always go smaller and take a bit more out(widen)to suit, 3/8 will always cut bigger and it will leave you with a sloppy key fit.

Bob

 

[Hood]

Mill spindle?

Nah, nothing as refined as that
Give you a clue, I often broach the haulers on boats in situ as taking them adrift is a major PITA on some.

 

[premmington]

Get someone else to do it for you.

This is what I do allot (farm it out) - my set of broaches only go to 16mm.

 

[RobCox]

I have always struggled with "broaching" internal keyways in pulleys on repair jobs.

What is my other option?

A shaper set up to cut internal keyways works for me.

 

[knighty]

You can get keyless taperloc`s, we have them on some of our kit and they don't slip. What's the application?

Bob

it's a tripe washer... this shaft is belt drive one end (input) and chain sprocket on the other end

motor is 980rpm, belt driven to this shaft about 2:1 ratio, 18kw (about 25hp?)

final drive is about 40rpm (after another shaft stepping it down again) , spinning a big drum with 1/2ton of tripe in it, in 1000litres water

machine is pre-war :-)

bearings never last long, no matter what I try they end up splashed with bits of grass/grit/poo and non of the sealed bearing types I've tried make any difference

it's seized a bearing and spun the shaft, so shaft is too small for the bearing now, I could build the shaft back up, but by the time I do that might as well go with a new shaft

I'd be worried a taper lock without a keyway might slip, there's a fair bit of starting torque on it

 

[knighty]

no v block, but I have clamping kit and a load of other bits I bought when I got the mill... then life got in the way and I didn't need to use it for what I bought it for so it sat there

I could lay the shaft in one of the T slots and clamp it down into that? I'll look for v blocks anyway

not too worried about tolerances, with the taper lock if it moves it should only move once - at worst it'll turn a little, jam against the keyway and then stay there?

 

[not done it yet]

so I'll need a 3/8 end mill? something to hold it?

As you are diving in with a new machine, have a practice with a piece of flat steel first.

Better to make an initial cut with a smaller than 3/8 slot drill and finish the slot to size, as this is your first attempt.

A collet of some description is required to hold the cutter (not a drill chuck!).

How you hold the shaft depends on what kit you have, but whatever it is will need to be dialled in carefully.

 

[Brad93]

it's a tripe washer... this shaft is belt drive one end (input) and chain sprocket on the other end

motor is 980rpm, belt driven to this shaft about 2:1 ratio, 18kw (about 25hp?)

final drive is about 40rpm (after another shaft stepping it down again) , spinning a big drum with 1/2ton of tripe in it, in 1000litres water

machine is pre-war :-)

bearings never last long, no matter what I try they end up splashed with bits of grass/grit/poo and non of the sealed bearing types I've tried make any difference

it's seized a bearing and spun the shaft, so shaft is too small for the bearing now, I could build the shaft back up, but by the time I do that might as well go with a new shaft

I'd be worried a taper lock without a keyway might slip, there's a fair bit of starting torque on it

I think I remember now.

You'll probably find it the bearings aren't lasting there is either Runout, bend in the shaft, misalignment or vibration causing them to go bad.

Dirt is a factor, could you move to pillow blocks with bearings you grease at regular intervals?

 

[knighty]

I have no idea which makes are decent or what I should be looking at...

Model Engineering and engineering tools online from RDG Tools Ltd Home Page (Engineering Tools) Tel 01422 885069 /884605

and

https://www.rdgtools.co.uk/acatalog/20-TITANIUM-SLOT-END-MILL-S---IMPERIAL---648.html

? (just because I found them quick)

 

[optima21]

Ive cut small keyways (4mm wide) in aluminium pulleys before in my tiny milling machine, using this tool and just advancing it 0.003 to 0.004 mm each cut

and taking a thin shaving out each time.

 

[knighty]

I think I remember now.

You'll probably find it the bearings aren't lasting there is either Runout, bend in the shaft, misalignment or vibration causing them to go bad.

Dirt is a factor, could you move to pillow blocks with bearings you grease at regular intervals?

that shaft was good and straight, no run out, the next shaft up takes more vibration (think of the drum as a tumbler) and those bearings last longer

no way to move this shaft anywhere else or protect them any better

I should grease them more... but life gets in the way :-(

 

[knighty]

Ive cut small keyways (4mm wide) in aluminium pulleys before in my tiny milling machine, using this tool and just advancing it 0.003 to 0.004 mm each cut

and taking a thin shaving out each time.

I'm ok on the pulley end, it's the shaft I'm doing

 

[sako243]

Nah, nothing as refined as that
Give you a clue, I often broach the haulers on boats in situ as taking them adrift is a major PITA on some.

Dremel or grinder

 

[Hood]

Dremel or grinder

Ha ha no, I use a broach.

 

[Hood]

I once snapped one but only one in 30 odd years is not bad

 

[123hotchef]

Ha ha no, I use a broach.

With a club hammer