Adding sprockets to 28mm acme vice screw

[PaddyR70]

Hi

90% novice here. I’ve added a vice on the end of my woodworking bench using two tail vice screws. The price of buying a twin screw vice was too much for me. I’d like to add sprockets and chain to achieve the same thing having used it a while and realising the awkwardness of clamping some stock. They would be situated at the ends of the screws under the workbench.
I have no mill. I have a router table , bench drill, angle grinder. I can see 28mm bore keyed sprockets but none with just set screws. I could take them to a welder maybe? Use the bench drill to drill a series of connected holes and channel it that way? Grind / drill two flat zones for set screw sprockets? (If they exist?)

How would you guys tackle this?

Help much appreciated

 

[rogxwhit]

Get the keyed sprockets and drill and tap holes in their bosses for set screws. Keys are a good idea too though - if you could cut keyways in the vice screws somehow.

You'll have to equalise the two screws ... which will govern their relative orientation, before you commit to cutting anything ... unless you're happy with the tooth pitch of the sprockets as a fine enough module of adjustment ...

How would you tension the chain? Or can you live with the slack?

 

[rogxwhit]

Set screws alone would need corresponding sockets in the vice screws - thus would act as keys - otherwise they might slip when your torquing up ...

 

[Lorenzl]

I found this a while ago: 3d Printed geared vice drive

 

[rogxwhit]

Can nuts be got that fit the vice screws? To sandwich the sprockets and help to keep them rigidly connected to the vice screws?

 

[Garden Shed Projects]

Have you considered using ply wood gears, you can make the centre however you like. You have a pillar drill and using decent 18mm ply wood you wouldn't have to worry about chain tension. Check out Matthias Wandells website below.

https://www.google.com/url?sa=t&rct...r/howto.html&usg=AOvVaw3Mw7QYs_Y95kTax67mdC1A

 

[rogxwhit]

I don't think that plywood or printed plastic gears are going to cope with the forces of a vice ... :-(

 

[Garden Shed Projects]

Check this out-



Or maybe this if you have too much time on your hands -

 

[rogxwhit]

Think I'll stay in the real world, thanks ...

 

[Lorenzl]

I remember somebody having wood leadscrews for this sort of vice for sale here.

 

[PaddyR70]

Set screws alone would need corresponding sockets in the vice screws - thus would act as keys - otherwise they might slip when your torquing up ...

Yeah that’s an idea. I’ve never tapped anything other than aluminium. I take it the taps can cut steel ok? I was thinking of just flattening the screw for the set screw but your idea is easier and better. I wouldn’t need the nuts you suggested below then either. Ta

 

[PaddyR70]

Check this out-



Or maybe this if you have too much time on your hands -

Ermmmm no

 

[PaddyR70]

Have you considered using ply wood gears, you can make the centre however you like. You have a pillar drill and using decent 18mm ply wood you wouldn't have to worry about chain tension. Check out Matthias Wandells website below.

https://www.google.com/url?sa=t&rct...r/howto.html&usg=AOvVaw3Mw7QYs_Y95kTax67mdC1A

I’m limited to the fact I’ve fitted the vice already. And the torque needed wouldn’t suffice unless I just lightly clamped them operated the two screws together after

 

[PaddyR70]

Get the keyed sprockets and drill and tap holes in their bosses for set screws. Keys are a good idea too though - if you could cut keyways in the vice screws somehow.

You'll have to equalise the two screws ... which will govern their relative orientation, before you commit to cutting anything ... unless you're happy with the tooth pitch of the sprockets as a fine enough module of adjustment ...

How would you tension the chain? Or can you live with the slack?

I’m hoping (that’s doomed then!) that I can just get enough tension by removing links. I had looked into tensioners but it’s over kill for what I need it for

 

[rogxwhit]

If you need to fine-tune it, you can get half-links ...

My thought about flanking nuts was that they'd make the sprockets rock solid (no wobble).

 

[rogxwhit]

I take it the taps can cut steel ok?

Yes. You might be looking at M6?

 

[PaddyR70]

If you need to fine-tune it, you can get half-links ...

My thought about flanking nuts was that they'd make the sprockets rock solid (no wobble).

Look what I found! Cheers
https://www.bearingboys.co.uk/Double-Split-/CADB28Z--28mm-Shaft-Collar-Double-Split-40386-p

 

[rogxwhit]

Not quite the same thing ... I'd hold off & see if you need something, first. Just allow room for them, if they turn out to be needed ... start with the sprockets on their own & see how it goes ...

 

[PaddyR70]

Not quite the same thing ... I'd hold off & see if you need something, first. Just allow room for them, if they turn out to be needed ... start with the sprockets on their own & see how it goes ...

Just rang Bearing Boys. Great company. I’ve bought tapered bush sprockets and bushes. They said it should hold for what I need it to without drilling etc if not I’ll just add set screws. Thanks for your help. 1108-28 Taper Bush (Dunlop) - BearingBoys

 

[ChaiLatte]

You'll have to equalise the two screws ...

An alternative is to use a shim washer between the rotating bit and the bit it pushes against. It might be a lot easier to adjust the thickness of a washer than to try to clock a keyway relative to a screw thread.

A second alternative is to rotate the nut into which the screw threads.