workbench + router/TC tables design - some questions

[SlowSteve]

Hello all.

I am in the middle of working out the designs for my first two "big" builds - a workbench and a combined router/Table saw bench.

I have a few questions on each one, but as they need to be the same height and will sit next to each other, I thought it best to ask them in the same question.

1) Workbench heights.
I seem to remember that there is a rule of thumb for workbench heights. One is that they need to be around 36" high, but there was another which I think was related to elbow height or something else body related which made the bench the right fit for the main user of it.
Can anyone tell me if I'm imagining this, or if there is some suggested guidance?

2) Joints:
I want a bench that will last until my grandchildren are using it. Does this suggest Mortice/Tenon joints - maybe pinned (draw-bored?) or can I safely use glued and screwed half laps for some of them?

3) Drawer bottoms:
The drawers are going to be holding a fair deal of weight - planes, hammers etc and so will be build strongly. However, if anything is going to fail over time, it will be the drawer bottoms. If I make the drawer body with dove tails, what sort of designs are available where I can have a strong drawer base which is occasionally replaceable/renewable?


combined router/TC bench.
Design considerations:
I am fairly space limited. Due to this, I need a bench on castors that I can tuck against the wall when not in use. It will be directly nect to the bench, above, so will need to be at the same height.
However, when in use, I will need to move it out by 90 degrees into the centre of the workshop, and so the bench will be moving often, which suggests large, lock-able wheels.

There seem to be two approaches to this.

Saw on the hard left, with router in the right hand extension - like this: http://i.ytimg.com/vi/gMR-jMFL7m4/maxresdefault.jpg

Or, saw more central, giving a wider left hand table - like this: http://www.finewoodworking.com/assets/u ... C_0002.JPG

As this is the first time I've used a TS, I'm not sure which path to go down. Certainly in the next 12 months, I can see myself doing more cross cuts, cutting dado's for example, than dealing with large sheets.

Does anyone have any thoughts on which design may be a better one to follow in my situation?

dust extraction:
For the router especially, dust extraction seems to be a requirement. I know that I want to have a cyclone chamber, the question is where to put it - again I'm looking for some guidance.

Option 1 - build it into the cabinet under the router - i.e. the chamber under the router becomes the cyclone chamber, with the shop vac attached outside. The big benefit is that there is no need for an additional cyclone chamber - which would likely be a plastic dustbin - but the downsides are that it feels tricky to design something that is simultaniously easy to empty but holds a vacuam well.

Option 2 - seperate cyclone chamber - easier to build and potentially allows more space, but does mean that I have a dustbin sized thing also taking space up, and when the bench moves, it's another thing to move around and so go wrong.

Any thoughts on either of these two are also much appreciated.

Thanks

Steve

 

[sploo]

Surprised that no one's replied to this yet.

My $0.02:

1) Workbench heights: Whatever is comfortable for you (based on your height/reach). I've got benches at roughly that sort of height (36"), and my bandsaw table is probably 3" higher. Both are fine, though that extra 3" might be too much for a bench that you work on.

2) Joints: If you're planning on making a frame from lengths of timber, and filling the spaces in with sheet material, then mortice and tenon is probably the "ultimate", but a half lap will still likely be plenty strong. Finger joints would also be good.

3) Drawer bottoms: You can slot a base into a dado that's cut into the back and sides, but have the front panel slightly shorter; such that the base is slid into the drawer from the front, then screwed onto the bottom face of that front panel. You'd then add a larger cosmetic panel on the front of the drawer (that's screwed from the back of the drawer's front panel). You could later remove the cosmetic front, unscrew the base, and slide it out. Personally though I'd just use some beefy sheet material for the drawer bottom and perhaps add some reinforcing strips to the underside (so you don't need to replace it)!

I'd go for saw more central, as that will support material to the left side of the blade. It should still give loads of space to the right for a large width ripping capacity (assuming your fence will go out that far). I'm planning on doing something very similar to the finewoodworking link, but hoping to build the area to the left of the saw as a sliding table.

Cyclone chamber: you're generally going to need enough height that I'd suspect it might be difficult to squeeze something effective inside the bench height (also bearing in mind that you'll lose ~10cm of internal cabinet height due to a large set of castors on the bottom). Having a separate cyclone might also be useful for hooking up to different machines, so just having a dust port (i.e. suitable plastic tube) coming out of the side of the router table might be a better option.