DIY Wagon Vise Question

[Scott Stewart]

I am trying to build a roubo bench using SYP and trying to design a DIY wagon vise using the LV tail vise screw, much like this one from Marko: http://www.sawmillcreek.org/showthread.php?215683-My-DIY-wagon-vise My current design is a L shaped block riding in rails, much like benchcrafted. My concern is about the piece of bench over the L shape. Right now, I have it sized at 2 inches wide by 1 1/2 inches deep x around 15 inches long. For comparision, the BC plan makes that piece of wood 1 15/16" thick. With the current design, I have the screw hole as low as possible to have 1/2" wood under it on the end cap. I worry that this piece may be too thin/flimsy. How much pressure/abuse does this area take? I can see a few possible fixes if required, some better than others...

1. Grind/cut off part of the flange to make the area I'm worried about over the flange thicker. I think using this method I can thicken the piece over the block to close to 2 inches. What would be the best way to do this? Angle grinder?

2. Thicken the top to 4 1/2". I am planning on building the top out of SYP bought from Beyer's lumber in St. Louis. I don't know if I can pick through the pile or not...is it offensive to ask? It's supposed to be #1 SYP but a lot of it still has some bark on it. I was planning on building the top from 2x6's. This option would allow me to thicken the top piece to 2 inches.

3. Leave it as it, I'm being neurotic.

4. Make the end cap extend 1/2" below the slab. I could drop the screw hole in the end cap down 1/2" and I think I would be fine.

5. Make the dog block a square rather than an L shape. This would leave a 4 inch wide hole in the top of the bench.

6. Wait 5 months to have the money to buy the BC wagon vise.

7. Buy a press screw. Cheap, but I like the idea of the screw moving trough the block. Keeps me from hitting the end of the screw sticking our of the vise.

Yes, I'm that crazy. My wife is tired of seeing me frowning in though, asking me what's wrong and me replying "Engineering problem on my bench"

Thanks for any thoughts. Scott

[Marko Milisavljevic]

I thought about various schemes to make the bench top above the screw thicker, but concluded would not be worth the trouble. That narrow strip of thinner top will make some small and possibly not perceptible difference in how much vibration you get when pounding something in that area. Generally you won't be pounding anything there - you'll position your mortises over a leg or somewhere between front legs. If you were repeatedly smashing that lip with a sledge hammer you may be able to crack it, but otherwise...

(to make sure I understand what you mean, I think you are concerned about the long thinner section of bench top in this photo)
http://www.sawmillcreek.org/attachment.php?attachmentid=285561&d=1395649095&thumb=1

[Scott Stewart]

Yes, thanks Marko. That is the area I'm worried about.