Vice or clamp for shaving

[Andy Mac]

Hi there,
I have been running some ideas through my head as I potter about the house doing the 'wifely' chores, trying to come up with a simple vice that could be used for spokeshaving or drawknifing at a workbench. This has come about from BobL's recent post on his beautiful home-made drawknife.
The problem with a standard front bench vice is it clamps the workpiece parallel to the bench, which is OK for planing; or vertical, but both are pretty difficult when using a tool like a drawknife. You can't work squarely with the piece, its a sort of offset body position... the vice should be 90* to where it actually is, maybe right on the corner of a bench if you have acces to the end! Working on spindle shapes like tool handles is best done with the axis pointing straight at your body, like it is in a shaving horse.
Sorry about that long-winded intro... so here is my first plan for such a thing. The moving jaw clamps downwards like in a shaving horse, but its tightened by thread, not foot pressure. Advantages- there is no extra hardware protruding down to the floor, and pressure can be variable. Disadvantages are the slowness of applying/releasing pressure (whereas a shaving horse is instantaneous), length of workpiece is limited by bench width maybe, and the top jaw may skew under working pressure. This could be alleviated by 2 threaded bars, or guide bars like a standard vice, but for that much trouble maybe use a real vice, mounted this way!!
Anyone seen something along these lines, or can come up with a more elegant solution?

Cheers,

[jmk89]

AM

My "solution" is much less elegant.

I use a holddown

to clamp the piece to the workbench and then use the drawknife. Sometimes, id the piece is thin, I put it on a piece of 4x2 (if I am being elegant, I have been known to use holt melt glue to hold it to the 4x2, but that was just 'cos the glue gun was out and hot at the time!!

If I need to hold the piece at an angle (eg to chamfer or make something roundish) I use a vee block the width of the bench.

The one advantage of this solution is that the piece being worked on is supported over most of its length

[BobL]

Good idea Andy. I would be interested in any solutions, especially if they contain a quick release of some kind. A couple of years ago I made this clamp thingo that fits in a bench vice. It's Ok for things up to about 250 mm long but the clamping is clumsy. Uh ho - can see an idea forming . . . . . .

[jmk89]

Another idea, like Bob's, is to hold the piece in a handclamp (Jorgensen, typically) and hold the handclamp in the vice.

[Andy Mac]

AM

My "solution" is much less elegant.

I use a holddown

to clamp the piece to the workbench and then use the drawknife. Sometimes, id the piece is thin, I put it on a piece of 4x2 (if I am being elegant, I have been known to use holt melt glue to hold it to the 4x2, but that was just 'cos the glue gun was out and hot at the time!!

If I need to hold the piece at an angle (eg to chamfer or make something roundish) I use a vee block the width of the bench.

The one advantage of this solution is that the piece being worked on is supported over most of its length

I can see that it would work, indeed I have a hold-down but mostly use it when chiselling. The work being supported its whole length is a double-edged sword in my view, it may strengthen the work, but also limits the access around the work...especially with tools like a spokeshave.

Good idea Andy. I would be interested in any solutions, especially if they contain a quick release of some kind. A couple of years ago I made this clamp thingo that fits in a bench vice. It's Ok for things up to about 250 mm long but the clamping is clumsy. Uh ho - can see an idea forming . . . . . .

I remember seeing that clamp, but the quick release feature is lacking, as it is in my plan. Over-centre toggle on a nut?? Back to the drawing board!

Cheers

[jmk89]

Point taken, Andy.

How about this for a thought?

The beauty of the shave horse is that in effect the action of using the drawknife or spokeshave increases the clamping pressure, but the pressure can be easily released to turn the piece. To make the increase effect automatic, we need a force that increases as a force is applied to the workpiece which will tend to pull it away from the "clamp".

Imagine that you have two pieces which slide one on top of the other with a clamping piece like on a shave horse but mounted on the bottom piece that pivots forward and down to hold the workpiece to the top piece. The top piece would have a pin behind the side bars of the clamping piece so that as the force of the knife on the workpiece pulls it and the top piece forward, the pin would increase the clamping pressure on the workpiece. A rough sketch is enclosed (nothing like as good as the work that you and Bob do, but I am a lawyer not a draftsman).

Attachment 70326
By sliding the top piece relative to the bottom piece, you should be able to get to a position where the clamp is solidly on top of the workpiece and the pin is against the side bars, so that any force which moves the top piece forward should increase clamping pressure. It may be that the clamping piece should be springloaded forward and down so that there is enough initial clamping pressure to ensure that the force applied to the workpiece will move the top piece forward, but it may be that friction will be sufficient.

What do you guys think?

[Andy Mac]

I'm liking it! Have to work on this more...gotta go, pick up kids and piano lessons etc.

[jmk89]

Andy and Bob (and anyone else who's reading)

Just realised that the previous version won't work. When the pin pushes against the side bars it will tend to rise up the bars rather than push the bars forward.

One solution would be to trap the top and bottom pieces together (replacing the T&G with a T slot - perhaps a pair of mating aluminium sections rather than timber...) so that there is no lifting effect when the pin pushes on the bars (or there is but it is overcome and the forward and down force on the bars predominates). Actually, I suppose that some T-track or sailtrack on one side and a series of cuphead bolts on the other could work. Here is a revised picture

[BobL]

I'm liking it! . . . . . .

Mee toooo. . . .

I presume the thing being shaved sits in between the two long arms?

Improvements?
I'd prefer to use the jig laying on its side and have two such clamps - one at each end.



Curving the clamping bar(s) would produce more sideways clamping pressure at the point where it is really needed

[Andy Mac]

I'm still leaning towards a top and bottom jaw arrangement, not side by side...unsure why I'm in that rut!
Here's another version, using some of the features of Jeremy's. I can't see the advantage of having pins, they seem to limit the clamping gap?
I think I need to knock up a quick prototype to see if the shaving force will be ample to hold the jaw hard against the workpiece, hence my inclusion of a spring assist.

Cheers,

[joe greiner]

This might, or might not, be suitable to the mission at hand. I thought I posted it earlier, but can't find it now. It seems my post list was truncated in one of the software upgrades, although the post count seems correct.

I mounted a machinist's vise vertically on my workbench. The sloping plank spans between the front rail and a leg of the bench frame. The vise is attached to the plank. I set it so that the lower jaw is flush (more or less) with the benchtop.

Aha! Found it by scanning my attachments:
http://www.woodworkforums.ubeaut.com...ad.php?t=49165
So no need for a new pic.

Joe

[jmk89]

I'm still leaning towards a top and bottom jaw arrangement, not side by side...unsure why I'm in that rut!
Here's another version, using some of the features of Jeremy's. I can't see the advantage of having pins, they seem to limit the clamping gap?
I think I need to knock up a quick prototype to see if the shaving force will be ample to hold the jaw hard against the workpiece, hence my inclusion of a spring assist.

Cheers,

I reckon it will work so long as there is enough friction between the top jaw and the workpiece. I can see that I am going to have to build my prototype to see if it works - now just to find an explanation for SWMBO why this has taken precedence over her requests

[malb]

Have not used a drawknife myself so I might be talking bunkum.
Watched the LN drawknife and spokeshave program on the woodworking channel the other night.
Presenter was using a stool about the size of a saw horse with a foot operated clamp at the head end. Sits at the other end, mounts workpiece into clamp, pushes with foot to lock, and into it. Takes about a second to reposition work as he works around it.
Claims that the big advantage over bench, clamps, vice etc is that the worker and workpiece are connected and work together for better control.
Might not suit your needs, but could be worth a look.

[BobL]

Have not used a drawknife myself so I might be talking bunkum.

Malb, the "shave horse" as it is called, is more or less where we want to get to but without taking up precious floor space. The closest thing I've come is sitting down and holding a guitar body between ones legs and then shaving the neck to size. "Ya gets to be one with the geetar"!

[Andy Mac]

Here's another approach, unsure about how it works exactly.

Cheers,