How to attach a HTD pulley to shaft firmly

[suspension]

Hello

What methods are available to attach a HTD pulley to the shaft? I am planning to use a pulley like this:
https://www.bearingsrus.co.uk/transm...ey/al21t5-12-2

I watched following video which discuss some methods. However above product does not seem to have the groove or a path for the set screw. What am I missing here?


Thanks

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[Jim Dawson]

You have to put in your own keyway (groove) and set screws. The best way is to use a taper-lock type of system that uses a tapered sleeve that compresses onto the shaft. Depending on the pulley size and shaft size that may not be available. https://www.bearingsrus.co.uk/transm...aper-lock-bush

[suspension]

Unfortunately taper-lock types are too large for my purpose.
When you say 'You have to put in your own keyway (groove) and set screws', do you mean that I need to mill the keyway and threaded hole for set screws?

[Jim Dawson]

Yes, mill the keyway and drill & thread the holes.

[handlewanker]

Nahh.......do it the easy way and bore or get a pulley to fit the shaft and attach it with Loctite.

Unless you want to remove the pulley constantly the Loctite method is the easy peasy way and you don't need to make the bore a press fit either, it's a slip on fit.

BUT MAKE SURE THE PULLEY IS RUNNING TRUE IF YOU'RE GOING TO BORE IT YOURSELF TO FIT THE SHAFT.

The second easy way is, after boring the pulley or getting it already bored, is to drill and tap a hole in the pulley boss for a grub screw, position it on the shaft then drill a dimple in the shaft to take the grub screw......commonly called a poor man's keyway.

All my motor pulleys are grub screwed with a single grub screw......and all the pulleys I ever bought came with a grub screw.
Ian.

[suspension]

Nahh.......do it the easy way and bore or get a pulley to fit the shaft and attach it with Loctite.

Unless you want to remove the pulley constantly the Loctite method is the easy peasy way and you don't need to make the bore a press fit either, it's a slip on fit.

BUT MAKE SURE THE PULLEY IS RUNNING TRUE IF YOU'RE GOING TO BORE IT YOURSELF TO FIT THE SHAFT.

The second easy way is, after boring the pulley or getting it already bored, is to drill and tap a hole in the pulley boss for a grub screw, position it on the shaft then drill a dimple in the shaft to take the grub screw......commonly called a poor man's keyway.

All my motor pulleys are grub screwed with a single grub screw......and all the pulleys I ever bought came with a grub screw.
Ian.

Using a grub screw seem to be easier.
I have looked in to following pulleys:
Aluminium 3mm HTD Pulley, 12T, 6mm Bore
https://www.ebay.co.uk/itm/Timing-Be...19.m1438.l2649

And they seem to come with threaded holes that I can use for grub screw?
Would this cause the pulley to be centric from the shaft?

Also, what type of shafts can I use? Would shafts designed for linear bearings (http://www.zappautomation.co.uk/mech...ound-rail.html) be used for this? Or is it an overkill? If so, can I just use a steel bar such as this?

[handlewanker]

Hi, yes, the steel bar you showed is stainless steel and can be turned quite easily, also the diam is probably a ground accurate finish

Drive shafts are normally made from mild steel but if the load has a big torque factor then a high trensile steel material is used.

NEVER use hot rolled mild steel shafting as the diam is rough, unless you are going to turn it to the size you want.

The convenience of using cold rolled mild steel is that the diam is pretty accurate for a nominated size so it's good to go off the shelf......a metal supplier can supply the length you need from stock.

You will also have to check the straightness of the material as cold rolled can get bent if it's stored or handled roughly.

Linear rail shafts are case hardened steel so there is no real advantage in using them and they cost a lot more.

The fit for a pulley on any shaft must be a close one.......a rule of thimb for a sliding fit is +.001" per inch of diam for the pulley bore size.........this is against the actual material size you get for the shaft as they can sometimes be undersize a thou or so.

If you machine the shaft yourself you ALWAYS make the shaft a standard size....whatever..... and the pulley bore oversize to fit it.....press fitting is not recommended EVER.

If you are boring a timing pulley hold it by one flange or the boss in a 4 jaw chuck as a 3 jaw can run out.... and indicate off the top of the timing pulley teeth NOT the other flange OD.

BTW.....if you're boring a pulley in a 3 jaw chuck stuff a rag or paper in the chuck bore to prevent the shavings getting into the scroll.
Ian.

[suspension]

Hi, yes, the steel bar you showed is stainless steel and can be turned quite easily, also the diam is probably a ground accurate finish

Drive shafts are normally made from mild steel but if the load has a big torque factor then a high trensile steel material is used.

NEVER use hot rolled mild steel shafting as the diam is rough, unless you are going to turn it to the size you want.

The convenience of using cold rolled mild steel is that the diam is pretty accurate for a nominated size so it's good to go off the shelf......a metal supplier can supply the length you need from stock.

You will also have to check the straightness of the material as cold rolled can get bent if it's stored or handled roughly.

Linear rail shafts are case hardened steel so there is no real advantage in using them and they cost a lot more.

The fit for a pulley on any shaft must be a close one.......a rule of thimb for a sliding fit is +.001" per inch of diam for the pulley bore size.........this is against the actual material size you get for the shaft as they can sometimes be undersize a thou or so.

If you machine the shaft yourself you ALWAYS make the shaft a standard size....whatever..... and the pulley bore oversize to fit it.....press fitting is not recommended EVER.

If you are boring a timing pulley hold it by one flange or the boss in a 4 jaw chuck as a 3 jaw can run out.... and indicate off the top of the timing pulley teeth NOT the other flange OD.

BTW.....if you're boring a pulley in a 3 jaw chuck stuff a rag or paper in the chuck bore to prevent the shavings getting into the scroll.
Ian.

Thanks Ian, very helpful.
I've ordered some shafts based on your suggestions.

[mactec54]

Hi, yes, the steel bar you showed is stainless steel and can be turned quite easily, also the diam is probably a ground accurate finish Ian.

How did you figure, that the ground bar in the link was stainless steel ??? did I miss something

Tt is either High Tensile Bar that is Hard Chromed and Ground or the Hardened Ground Bar which is 58 to 64 Rc, this shafting is for linear Bearings to run on, the Hard Chrome Bar is workable, but the Hardened Ground Bar is not

A +.001" is a sloppy fit, on a size like this, a sliding fit starts at + .0002" anything over .0005" on a size like this would be a loose fit

[handlewanker]

How did you figure, that the ground bar in the link was stainless steel ??? did I miss something

Tt is either High Tensile Bar that is Hard Chromed and Ground or the Hardened Ground Bar which is 58 to 64 Rc, this shafting is for linear Bearings to run on, the Hard Chrome Bar is workable, but the Hardened Ground Bar is not

A +.001" is a sloppy fit, on a size like this, a sliding fit starts at + .0002" anything over .0005" on a size like this would be a loose fit

Mac, as you appear to be going senile and have poor eyesight......at the end of his post he said "......like this"....the THIS part is another link and refers to 8mm diam stainless steel material

The previous link detailed a steel bar SFC8 which is a high chromium bearing steel, 8mm diam case hardened to 68 Rockwell for a depth of .8mm to 2.5mm........if you break through the case it can be worked normally......but you wouldn't know about that.........NOWHERE does it state that the steel bar is chrome plated.

You are totally an armchair nitwit when you misquote out of context.......the size reference I stated is PER INCH OF DIAM...........at .0005" for a 1" diam shaft that is considered a light press fit......size for size is a real press fit.......the rule of thumb is applied pro rata against whatever size you are working with.

Being not of the practical World or any working environment you just quote graphs that you think are valid and make statements out of context to the topic........get real, the sizes that I stated have been used for donkey's years in the trade and are the normal fit.......BTDT.

It seems you are revving up to be argumentative once again.....well talk to yourself.......I've finished.
Ian.

[mactec54]

Mac, as you appear to be going senile and have poor eyesight......at the end of his post he said "......like this"....the THIS part is another link and refers to 8mm diam stainless steel material

The previous link detailed a steel bar SFC8 which is a high chromium bearing steel, 8mm diam case hardened to 68 Rockwell for a depth of .8mm to 2.5mm........if you break through the case it can be worked normally......but you wouldn't know about that.........NOWHERE does it state that the steel bar is chrome plated.

You are totally an armchair nitwit when you misquote out of context.......the size reference I stated is PER INCH OF DIAM...........at .0005" for a 1" diam shaft that is considered a light press fit......size for size is a real press fit.......the rule of thumb is applied pro rata against whatever size you are working with.

Being not of the practical World or any working environment you just quote graphs that you think are valid and make statements out of context to the topic........get real, the sizes that I stated have been used for donkey's years in the trade and are the normal fit.......BTDT.

Ian.

I did say, did I miss something, and obvious I did if there is a link to the stainless steel shaft, Post the link I don't see it in his post I'm blind and senile, are yes found the link

We can see who the nitwit is, + .0005 is a slide fit, for 1" diameter, but you would never know, because you would not have anything to measure .0005" with, little alone .0001" you are just a old journeyman fitter and turner, hack at best, but of course you are just talking to the trees out back again right

[handlewanker]

I did say I was finished as in nothing more to say.........you go find a tree and talk to it if that's what you do..