LV Twinscrew owners - How tall for the Jaws?

Doug Shepard

In Memorium
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772
Location
Waterford, MI
I've found tons of LV twinscrew threads but cant seem to find what I'm looking for. I know you need a minimum 6" tall jaw height, but what are you using? Right now I'm planning a 4" workbench top that would need a minimum 8-1/8" tall jaw if I'm doing the math correctly and give me a throat depth of about 4-1/2". For some reason this sounds pretty tall and I'm wondering about thinning out 2 channels underneath the top for the screws (maybe down to 3"). What's everybody else using?
 
Doug,

You will need 4" for the bench top plus clearance from the bottom of your benchtop to the top of the lug nut plus the distance from the top of the lug nut to the bottom plus some more clearance to the bottom of the jaw. (If I remember clearly.:huh:) Anyway the 8" figure you have calculated sounds about right. I have a 3" benchtop and I made jaws somewhere in the 7" range. I know your doing it :D but most important when installing this jaw is to follow the manual. Have fun and post pics.
 
Alan
Sorry I didn't answer your question sooner but I've been struggling for a few days with Sketchup and Dave Richards straightened me out enough to get this rough sketch put together.

The core is plywood like one that Sam Blasco did. The legs are Noden Adjust-A-Bench legs, with the twinscrew on the RH end, and a Tucker vise in that wierd notch on the front that will let the rear jaw face be flush with the bench.

For right now, I haven't decided on the joints for the hardwood edging and am just showing these butted but will probably go with dovetails for the LH end. I'm wondering about the RH end that is also the rear twinscrew jaw though. I'm wondering whether I should avoid gluing it on and just use the method LV's instructions show, using the cross dowel nuts to bolt it on? Or could I (should I) go ahead and glue it on as well as dovetail it to the long edges? I'm not sure I like the idea of a thinner glued on table edge then the thicker jaw bolted to that, but if that's what I should be doing, I want to figure that out now as it will affect the plywood core length.

Benchtop3a.jpgBenchtop3b.jpg
View attachment Benchtop3.skp
 
I always thought that that vise would be really great to have on a bench but I do not have a mechanical engineering degree so I guess that I will just forget it. Sounds like more trouble than it's worth.
 
I was actually planning on getting the Emmert clone for the longest time and at the last minute switched to the Tucker just for the quick release. FWIW I did investigate the possibility of setting this in flush like the Emmert type (like shown here http://www.shavings.net/EMMERT.HTM). Other than needing 1.5" on either side of the jaws for rotation there doesn't appear to be any vise or clearance issues but one major obstacle skotched the idea for me. The way the mounting plate attaches to the front face rather than mortised into the top means that there's no way to insert or remove the large hinge pin unless you have an open end. So there's no way to hang or de-mount the vise without taking the whole mounting plate on/off with the screws and with the vise attached for the ride. So I think it's do-able but not very appealing and sort of nixes the allure of being able to have additional mounting plates/stanchion bars to allow for quickly moving the vise to different locations on the bench. Not sure I'd even want that option, but it's there. In the end, I'll just be leaving an open end on the left and I changed the quick release lever mechanism from the RH to LH side of the vise, which makes it easier to get the hinge pin installed without having to remove the tension spring then try and get it re-attached in the tight confines of that notch area.

I was originally thinking of doing through DT's like the one Mr. Blasco did on his plywood wood bench (http://www.sawmillcreek.org/showthread.php?t=22081), but the dado/tongue and Half-DT's are appealing too. Gonna have to think on this some more.
 
...

I'm slightly miffed at your bench in the sense that you didn't scrimp on the hardware whatsoever, you've got about $800 worth of hardware, and then you're using plywood layers for the top...:huh:

There's a few reasons for that.
1- I've got $800 worth of hardware in the bench already:eek:. Actually it's more like $1600 :eek::eek: including the Noden legs, casters, and 1-rail brackets. Best guestimate on hardwood available around here would have been another $500.
2- I want to get this done quick. I think by the time I milled up hardwood I'd run the risk of cold temps and glue problems. I'll need to have the bench top built and everything assembled before cold weather makes me park a vehicle in the shop.
3- It will reside in an unheated, uninsulated garage shop with big swings in temp and humidity through the year. I think the ply core stands a better chance stability-wise in that environment.
4- I actually think the edge up ply veneers on Sams bench looks cool although I realize it aint for everybody, and it's certainly not traditional (but then neither am I).
5- The ply top investment wont cause me all that much pain if I decide in a few years that I hate it, need to re-design it, want to change to hardwood, etc. I wont kick myself as hard if I decide it needs to be pitched and redone.
6- I get to stymie true Neanders:D
 
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Homey I Shrunk the Bench

I thought I'd toss a mini-gloat in. This is the dumpster dive slab I put to use mounting the Tucker on. It allowed me to take a boat-load of measurements and figure things out for the real bench layout.
TVise1.jpg
 
FWIW I bought 3 sheets of 1/2 "Paint Grade" birch yesterday that was only $28.50 ea. These are for the horizontal layers and whatever's left of each sheet will go towards cutting some strips for the vertical layers but I'll need more for those. I tried in vain to find somewhere around here that had ApplePly and I wanted continouus pieces rather than working with the 5x5 Baltic Birch. Anyway, this stuff is 7-ply (9 counting the face veneers) just like Baltic Birch and is 4x8. It's flat, there's no voids, and the faces both look good, although whatever the core veneers are look a tad fuzzier than Baltic Birch so the remainder of the vertical layer stuff I need to buy will probably be BB.
 
OK. This SU stuff is sloooowly coming to me. I managed to get these done. I mainly wanted to check the screw and leg panel proximity. Managed to get my horizontal ply layers cut today as well as strips for the verticals out of what was left. Need to figure out how much more I need for vertical strips and pick up some more but probably out of 3/4 BB for the rest.



Here's a shot underneath. It's just gonna fit.
Benchtop5a.jpg


From the end.
Benchtop5b.jpg


And got rid of all the ugly butt joints.
Benchtop5c.jpg
 
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