New Woodworking vice with a difference

[JohnBrown]

Hi John
The way I see it is this.

When not under tension the bar just slides in and out in the nylon bushing, unimpeded by anything, because there is a clearance hole in the disk.

When the handle is tightened, the gear moves clockwise, driven by the key/slot arrangement (the one we've not seen but believe must exist) and that gear (pinion) moves the wedge-shaped rack to the right.

As the wedge moves to the right, the disk is tilted, because it is being pushed at one point only; so it no longer clears the rod, but grips it and moves it in a wee bit. That small amount of movement is the grip of the vice.

Sorted!



But even if we could buy all the bits, would it really be much cheaper, or indeed even as good, as paying the bloke who already seems to know what he is doing?

Still, it's nice to have the understanding, isn't it?
S

Which is exactly what I tried to write!
I still don't understand where RR's ratchet comes in though...

 

[RussianRouter]

Sorted!



Still, it's nice to have the understanding, isn't it?
S

The easiest way to explain it is...think of how the clutch in a car operates.

Personally you do not need a big long vice like that?

ie a 14"/15" wide and you don't need the rack just the gear,pillow blocks,rods,washer and spring and you have a simpler version of it.

 

[JohnBrown]

RR wrote:

The easiest way to explain it is...think of how the clutch in a car operates

Ah! That's probably why I don't understand - I drive an automatic.

But how does this ratchet help with gripping the smooth bars or tightening the vise.

 

[Benchwayze]

If it's a thread that advances the front jaw against the rear jaw, the only place I can see on this design, to hide a thread is inside the wooden boss.

If there was a thread on the outer end of each rod, and a captive nut inside the boss, would that work?

I fear the image isn't good enough to see exactly how the gearing ans casti=ngs are made up. It looks like there is a spring between the large disc and the rea of the casting.

Can any of you egineers tell me if a threaded rod would advance through a half of a nut? I.e a threaded cradle? I don't have the means of chopping a nut in half to find out. :lol:

John

 

[Benchwayze]

George,
If you mean the width of the vice, along the benchfront:

The purpose of the space between the rods is to provide a means of holding wide pieces without anything fouling the workpiece. Such as when making dowvtetails in a 2 foot wide carcass piece.

John

 

[Steve Maskery]

John
There is no threaded rod involved. The jaw is pushed a little bit by the wedging action of the rack (the rack is slightly wider at one end than the other). As the wedge is pushed to the right, it pushes the top of the disk back, jamming on the rod and tightening it up just a wee bit.

JB


S

 

[9fingers]

If this is the correct explanation - and I think it may well be, the bit I don't like about the design is that as the final few degrees of tightening is being applied to the bar, it is also being gripped ever tighter by the clamping ring which will lead at best to wear and at worst to grooves dug into the bar.


Bob

 

[Steve Maskery]

True, Bob, but I bet the rods are hardened, and this technique works on trigger clamps without noticeable wear, doesn't it?
S

 

[Benchwayze]

Well either way Steve, it got me thinking and that can't be bad for my old grey cells!

It's been an interesting thread (No Pun Intended) and has given me food for thought, along the lines of those trigger clamps! I think I could use some in the shop!

Cheers
John

 

[RussianRouter]

This is the cheapest place I've found for the precision bars,even on ebay they're dearer than this place and price depends on diameter and length of them.

http://www.motioncontrolproducts.co.uk/ ... ucts_id=89

I had a link for the pillow blocks buthaving trouble locating,as soon as I have found themI'll repost.

 

[RussianRouter]

Dang! it was ebay for the pillow blocks,30mm bore as the rods previous post.

http://cgi.ebay.co.uk/UCP206-Pillow-Blo ... 3354456ebe

 

[9fingers]

True, Bob, but I bet the rods are hardened, and this technique works on trigger clamps without noticeable wear, doesn't it?
S

The rods have to deform a little for that sort of clamp to work.

The big difference between clamps and this explanation of the mechanism is that two parts are rotating with respect to one another and in a trigger clamp this is not the case.

Bob