Flattening spoil board.

[SIBUD]

So later on today the mailman will bring the large diameter bit I will use to flatten my spoil board.

So I assume one makes very shallow cuts while having the bit move back and forth with some overlap between passes?

Is there a standard routine somewhere that I could use and just change the parameters for my bed size?

Any info appreciated.

[Adrian]

I do it by drawing a rectangle the size of my table plus the diameter of the bit (that bit depends on whether you have open ends and/or sides on the table) and create a pocket toolpath with the raster option set.

Some control software (like the Shopbot one) have routines that do spoil board surfacing as well.

[SIBUD]

I do it by drawing a rectangle the size of my table plus the diameter of the bit (that bit depends on whether you have open ends and/or sides on the table) and create a pocket toolpath with the raster option set.

Some control software (like the Shopbot one) have routines that do spoil board surfacing as well.

easy peasy! Thanks.

[tmerrill]

I suggest you use a ramped entry with a bit like that.

The pocket toolpath offers the option for Ramp Plunge moves which is perfect for that application.

Tim

[SIBUD]

I suggest you use a ramped entry with a bit like that.

The pocket toolpath offers the option for Ramp Plunge moves which is perfect for that application.

Tim

Thanks for the tip Tim. What cutting depth would you recommend for my first pass with the bit zeroed to the top? I was thinking very shallow for first cut to see how close it is. If it cuts all the way across the spoil board, then I wouldn't have to take off any extra. If the first pass left areas untouched, I could run it again a little deeper.


Are there any other parameters that would have to be set with a ramp plunge move?

Appreciate all advice.

[bbiehl]

I recently got a 2-1/2" spoilboard cutter (Amana) to flatten my workpiece. The first time I used it I tried going down .06" at 10ips and the cutter stalled (I have a 3hp water cooled spindle). I now go down .03"/pass at 5 ips and it seems to work ok ( I also overlap 50% at 12000rpm). Ramping is a good idea, I will also do that in the future.

-brian

[Rcnewcomb]

I now go down .03"/pass

I agree, 0.03" is a good starting point.

[Mike-S]

Why don't you manually jog around the bed and touch-off the bit in a number of places? Check the DRO to find the max high and low. Then set up you surfacing cut from that info.

[fixtureman]

I only cut it .010 the first time on a new spoil board then .005 when needed. This on a 48x96 table.

[SIBUD]

Thanks for all the suggestions.

[Eddiem]

I did mine by using my keyboard and running the bit back and forth myself that way i was able to go right to the edge of my cutting area for my cnc it did not take to long but made a big mess as i did it with no dust foot on so i could see what i was doing..

Maybe not the best way to do it. LOL

[fixtureman]

You can draw your pocket just a little larger than your table and it will surface it to the edges.

[Lazerbee]

Why not cut an X and Y straightedge into the spoil board during the flattening process?

[irishwoodworker]

A great idea, Lazerbee. I did mine after flattening and should have done both together. I also made two MDF fences, one for each axis. Each has a dead straight bottom strip (screwed to the fence (top)) part that rides against the indexed ends/sides of the spoil board. I drilled two holes at the appropriate places and attached two closet bolts to hold in place. I did not worry too much about getting the fence part (top) square ahead of time and just ran a 5mm cutter along each axis to square them up after snugging up to the spoil board. I used Peter Pasuello's great wingnuts (https://www.dropbox.com/sh/h8qjq6fxnpe4 ... 1oTf7-gm3a) although I believe Peter credits another CNC maker for the original idea.