Table position/size

[denmanmarine]

Hi all,

Just setting up the table on my PRS Alpha 120-60. The table drawing and instructions show the table size to be 120 inches long and 60 inches wide. Are there any drawbacks to having the table lower layers a couple of inches bigger all round and then the spoil board at 120" x 60"?

regards,

Andrew

[adrianm]

Some people cover the whole surface (as I have done) and others like to leave a gap around the edges for clamps etc.

Both have their merits but I don't think there are any reasons why you shouldn't although I don't run a vacuum on my setup.

[myxpykalix]

If it was me i'd leave room for clamps. There is always going to be a reason why in some instances you either can't use vacumn and need to clamp things down. There will be instances where you will make jigs to hold smaller peices and need to clamp down those jigs.
I'm not clear on what benefit you gain by covering the whole surface? Your carriage will only go so far over anyway.:confused:

[steve_g]

The reason my table is covered stem to stern is that my small shop requires the under table area for storage. Since I don't use vacuum hold down, that area isn't full of plumbing. The "full" table allows a degree of sawdust control under the table.

SG

[jerry_stanek]

I made aluminum troughs to fill in the area. That way I can remove them to use clamps also the are bent in an L shape so when I cut Slot wall panels it keeps the dust out of the t rail aluminum extrusions. Easy to suck up the dust on cleanup

[adrianm]

Like Steve my whole surface is covered because I have large storage boxes on wheels underneath it and I don't want them full of chips and dust off the top.

Clamping is not an issue as I have t-track that runs down the whole length of the top including the areas outside of where the carriage will reach so I can use that for any operations that require clamping. As most of what I machine is in 8x4 sheet format they're used mainly for clamping that down.

I ran it for a couple of years with the standard setup and then another few months with removable panels but what I have now works best for me.

[ssflyer]

My setup is like Adrian's and Steve's and for the same reason - dust control. Also, whether a valid reason or not, I like to think it adds a degree of stability to the entire setup - I actually used the ShopBot to cut my spoilboard for the T-Track. I like the idea of a machine making its own parts. :D

[bleeth]

I hear you Ron: Don't you wish you could figure out the file to make your Bot self-replicating?:D
Call them the Botlets!

[denmanmarine]

Thanks guys.

Another question regarding the spoil board if I may.

I just glued down the second table layer (18mm MDF over 25mm ply base) and I have added 2" all round to the 120 x 60" dimensions. I was looking to use a 12mm spoil board but before I position it, I was going to power up the machine and look at the extents of the cutting area first. Should the spoil board be the exact dimensions of the available cutting area? I can see the advantage to this when it comes to machine it down but open to suggestions.

Andrew

[adrianm]

I'd say make it the same size as the cutting area, much easier for planing off that way.

The actual area depends on where you position your stops and it will be offset because off the motor position on the carriage.

[steve_g]

Whatever you do... Don't make it larger than your cutting area. I ran into a situation like this when I was helping a friend. The cutting area became recessed from eventual surfacing and prevented indexing of material.

I have a 1/2" dado plowed into my table at the x and y origins... This lets me insert a temporary backstop while loading and positioning material.

SG