Flattening TS top

[Eric The Viking]

Thanks for that Dimmaz - I love it when people find elegant solutions like that!

Out of curiosity: I assume the trunnions are proper ones (quadrants, well below the top), but I'm curious as to how you're going to fix the insert plate...

Also, it might be worth storing the original table somewhere flat, and, if we have a hot summer, outside where it can warm up, and checking it occasionally, in case it recovers. I also think the problem might be from extension tables (if they were heavy cast ones). It can't have been like that ex-factory, so something caused it over time. What's the original like underneath - are the webs minimal, or was it quite well reinforced across the centre?

 

[Scottdimelow]

Cheers Eric.

You can't see it very well in the picture, but there are a couple of pieces of flat bar width ways across the opening. I'm going to cut these down so there are just 4 tabs sticking out, I'll then drill and tap them for grub screws. This way I can level the plywood inserts.

I had to make a few hollows for the trunnions etc, see pic. I actually didn't loose any cut depth, as the spindle arm used to hit the underside of the table. It can now reach it's full height.

I agree about the extensions, I think that's definitely the cause here. The original seems to have decent webbing underneath, however it's the first one I've had so I can't compare it to anything. I like the idea of leaving it in the sun, I could do that today actually

 

[AES]

Wow! I haven't even got a TS, but (I think) I recognise skill and lateral thinking when I see it. I didn't even know about special reinforced concrete and thinking about it I have little idea of how I would go about it if I had to. But that cast TS top looks excellent. Well done Sir.

Krgds
AES

 

[Scottdimelow]

Thanks, AES. It's not that specialist really, you just watch your water to cement ratio, and chuck a load of fibres in

 

[deema]

I'd love to know how you actually made the new top, the finish you've achieved is stunning. The simply brilliant solution you've arrived at has legs for lots of other problems where people want to make larger, different work tops for their machines, or even new fences. Id love to solve a problem I've been thinking about using your solution.

 

[Scottdimelow]

I did take photos, but accidentally clicked delete instead of download! Gone forever.

Simply put It's made upside down. The form is all made from melamine chipboard, of which I cut strips of the final depth of the top. I made a simple frame and screwed this to the board.

I then marked out where everything was, channels insert hole etc. I cut the alu track and stuck it in place with a few drops of superglue.

For all of the holes and voids I used polystyrene. The pieces for the voids have to be suspended.

The concrete mix uses a self-consolidating admix, this means no vibration is needed and it flows very well. It also helps the concrete cure quickly, I could of probably de-moulded in 6 hrs but I left it overnight.


What's the problem you have Deema?

 

[deema]

Thanks for the details, my problem is not a problem like yours, rather I've been looking to make a different style of platform / drill table for my pillar drill. Wood simply isnt sufficiently stable, and I don't have the kit or ability to fabricate out of steel. I'd looked at making one using Fiberglass, but concrete would be far simpler, cheaper and easier to mould I think. I've also now started to think about making some extension arms for my spindle moulder the same way. In fact the genius of your solution has really started to make me think. I think it's probably a better solution than cast iron for wood working machine tops, easier to make, as hard wearing, cheaper to produce, no residual stress, simple to repair the list goes on,.

 

[doorframe]

Reading through this thread I was coming up with a few ideas how to overcome the problem, but what you've done is brilliant. I would never ever have thought of that.

Can you give a bit more info on the type / grade / manufacturer of concrete you used. Was it just concrete and fibres, or were there any more additives?

=D> =D>

 

[n0legs]

Excellent, that's two thumbs fresh =D>

 

[rafezetter]

If I had read this post sooner I would have suggested doing this - while looking for ideas for a CS based tablesaw over a year ago I came across this build writeup:

https://woodgears.ca/reader/homemade_tablesaw.html

Which mentions a cast concrete tabletop and how he made it.

Deema - might I suggest if you do make a better sub table for your drill press that, if it's going to be much wider than the metal plate, as well as adding fibres add a couple of lengths of threaded rod to reinforce it along it's length. Dimmaz didn't need to do this as his top is supported evenly, but a central support with ovehangs would benefit from a bit of internal support other than the fibres.

Another possibility is concrete board (I don't know the actual name for it) - I came across this months ago when I was looking for a strong, heavy but thin material to use as a sound deadening solution for a project I have on the go, and my builder mate had some offcuts he'd used in a wet room to line the walls instead of plasterboard as they were using heavy slate tiles. I'd never seen it before; when cut it looks internally like chipboard but instead of glue used to bind it's concrete, so it doesn't have the small voids of chipboard - it's 100% solid - it's extremely tough, stays flat and is only 12mm thick. The 1mtr x 1mtr sheet he gave me was deceptively heavy, I almost dropped it I wasn't prepared for the weight.

It looks like this: http://www.musterkiste.com/en/holz/pro/3302_Cement-bonded_wood_particle_board.html

Edit: one brand name for it is Viroc - dunno why they say "flexibility of wood" though unless they mean uses as my sheet is anything but flexible.

I don't know how much it cost, but for a solid stable flat surface this is what I'd use.