Your idea is really great. However, that seems to work only if you use thin boards, because the deviation produced by the angled rail works much better when the vise is nearing the end, almost closing. Have you experienced biting much wider woods, maybe 6 or 8 inches, with the vise very open? So I guess in that situation you will suffer some racking.
I just completed my guide for the leg vise with your ideas, it works great and the operation principle is so good. thanks a lot, great job. Greetings from Brazil
Like it. I hope to soon build one out of thick wall Steel tubing and use as a Blacksmith post vice. I will probably use heavy caster wheels instead of the bearings because of striking with hammer. Even tho it's not a tru Smith's post vice it can still be very ridged and keeping the jaws parallel as you have done is a big improvement over the traditional post vice. Thanks.
Isn't one of the advantages of the pin that it provides leverage? The distance from the screw to the pin is more than the distance from the screw to the work, and when tightened, the screw is a fulcrum, putting more pressure on the work. Does this design keep this advantage?
Intersting question. What you wrote is basically correct. The force exerted by the screw is split amongst the pin and the piece being clamped. The farther the pin is from the screw, the less of that force is reacted by the pin (and the more force by the workpiece). It is equivalent to say that the force on the pin is the exact amount required to keep the vise jaw from rotating. Pinless vises use various mechanisms to keep the jaw from rotating, most (all?) of which boil down to reacting some of the screw force on the jaw at some distance below the screw, just as a pin does in the traditional design. My design is a little different from the rest because is keeps the jaw from rotating by putting a force on the end of parallel guide (through the table saw bearing), rather than directly on the jaw. The result is effectively the same. You might think of the distance between the nut of the vise screw and the table saw bearing in my design as the equivalent of the screw-to-pin distance of other designs.
Lars Parrington You think it's the wooden track that got compressed, or the main (bigger) bearing that got compressed and would need to be changed? Also; do you remember what type of wheel you bought from McMaster? Looks like a benchcraft killer to me. (btw; I'm really excited about your video. I'm in the process of building my roubo and your video may change quite a bit my plan!) :D
djang000 Good luck with your bench build. I had a lot of fun building mine. The reason it doesn't glide as smoothly doesn't have anything to do with the wooden track or the rear bearing. It is probably rubbing between the parrallel guide and its mortise. The bench has moved quite as the wood dries out. I just remembered a modification I made to the vise, which may or may not have any relevance to other users of this vise design. A few months ago I attached a bungee cord between the back of the parrallel guide and the underside of the benchtop. As I closed the vise, the parralel guide would sometimes get stuck in its mortise enough to jam. The end of the parrallel guide with the big bearing would drop and I'd have to kick the bottom of the vise to free it up. This is due to the increased friction mentioned above. The bungee keeps the guide from dropping and thereby prevents jamming. I suppose this is really just addressing the symptom rather than the root of the problem (too tight mortise), but it works for now.
djang000 Almost forgot, the handwheel was mcmaster's p/n: 6025K13. It is just a rough casting. It will require some machining, and optionally some smoothing.
This was my first stop searching for a leg vice design that doesn't require expensive hardware it will also be my last. Love the concept. I have some old bearings I replaced in my table saw arbor and I'm thinking the one on the top of the beam can be captured in a slot so it's not visible. I really like this design, thanks.
hi seaotter. good luck with your bench build. you might be interested in a woodcentral thread discussing some of the flaws of this design. see the second link in the video description.
