Thread: Is there a name for pulleys with the grub screw recessed into the groove?

Hello, I have bought a pulley which has the grub screw offset which makes it too wide for my needs - is there a name or term for pulleys which have the grub screw recessed in the belt groove so its only as wide as the groove?

Alternatively, could I drill and tap the one I have and cut the wide part - or is there a structural reason for the extra material?

Aluminium V Pulley B Section Single Groove Standard Keyway Australian Made - Australian Pulley Co

This is what I have ^

Hubless pulley. Honest.

Thanks for the quick answer!

Originally Posted by catmanjan

. . .is there a structural reason for the extra material?. . .

Naturally, if it is a stamped pulley or one with an especially thin web then a hub is a structural requirement if it is to be mounted to a cylindrical shaft. If it is made from a solid slug with straight sides and the load requirements do not mandate a long key, you can remove the hub and relocate the grub screw. The one you link to has a reduced center section so you would want to leave at least enough hub to be flush with the sides of the pulley rim. Depending on what the other side looks like you might also need to use a smaller grub screw.

catmanjan,

Another option is to use a pulley with a taper lock bush (if you have access to one end face of the pulley).

Taper lock pulleys have a bush which pulls up flush with the pulley face.

If you don't mind something a bit wider than the pulley, then the Bi-Loc (Biloc, Bi-Fit, Mi-Fit) pulleys are another option. On this system, there is a flange and bolt heads which are wider than the pulley.

Thanks, I have used taper lock pulleys before - I am trying to find one that suits my needs, unfortunately I can't get a taper lock 2" V Belt A section with 1 inch bore, I think the taper lock is too big for a pulley this size

I will try and remanufacture mine into a hubless pulley

In the Dodge or Martin brand, the 1008 series taper lock bushing is the smallest one that goes up to 1” bore. Unfortunately, Martin does not appear to offer the size sheave you want that will accept it. You will likely just have to drill and tap a stock bore pulley to put the set screw in the bottom of the groove like you want it.

I haven't seen every sheave ever made but I have seen a whole bunch, and not one ever had a setscrew situated in a groove...I think it's poor engineering and something that a reputable manufacturer would never do. I've done it occasionally, but I'm just a hack.

Stuart

Why would it be poor engineering? The belt does not touch the bottom of the groove.

A common practice in low torque load, small machine applications.

The grub screw often retains the parallel key that drives the pulley/shaft.

Originally Posted by Mark Rand

Why would it be poor engineering? The belt does not touch the bottom of the groove.

Because that radius is too tight for the relevent belt section.

Browning lists them as "steel sheaves" type 1F.

Originally Posted by Peter S

catmanjan,

Another option is to use a pulley with a taper lock bush (if you have access to one end face of the pulley).

Taper lock pulleys have a bush which pulls up flush with the pulley face.

If you don't mind something a bit wider than the pulley, then the Bi-Loc (Biloc, Bi-Fit, Mi-Fit) pulleys are another option. On this system, there is a flange and bolt heads which are wider than the pulley.

Peter, these are called taper locks and they are brilliant, but they are only available in larger sizes. However, check out Tsubaki's line of "Power Locks". They have several styles, many of which are very suitable to small shafts and pulleys, but be prepared for their very high cost. It makes your eyes water!

Originally Posted by Limy Sami

Because that radius is too tight for the relevent belt section.

Because, if the belt is in contact with the bottom of the groove, then it is not gripping the sheaves and will be slipping!

The need for a set screw in the crotch of V would indicate to me there is little or no hub to put an appropriate set screw or screws into. This would also indicate to me a single belt sheave which mean there is little axial support for the sheave. This is why I felt it was a bum deal and you would not see a sheave make for any real service with that construction. I could be all wrong on this though and would be happy to admit it.

Stuart

Alternatively, could I drill and tap the one I have and cut the wide part - or is there a structural reason for the extra material?

When you cut off extra hub leave as much on as will cover the shaft to give lateral support.

Would it be possible to run the hub toward the bearing or motor and adjust the system side to side to make the belt run true?

Paul

Originally Posted by Mark Rand

Because, if the belt is in contact with the bottom of the groove, then it is not gripping the sheaves and will be slipping!

I think we may be at cross purposes my statement was because an A section Vee belt is unsuited to a 2'' dia pulley as per the OPs quest. ***

Ref Page 26 here http://www.tecnicaindustriale.net/ch...elts_gates.pdf

*** yes I know it's done - especially on ''low end'' machinery, but it ain't right nor is it efficient.

Yes, AX might do the job far better.

Myford were culprits for having vastly undersized motor pulleys.