All has been working well but still an issue with flex/unevenness in the spoil board.There have been a few good suggestions and modifications in this area so I’m stealing the ones I like.
@DavidWestley featured a spoil board that had t-track inserted for clamping. THis is what I’m basing my design on.
One change is that I’ll use aluminium sail track as it’s a lot cheaper than t-track (about $A12 for 5 metres).
Original spoil board is removed and two pieces of MDF are fastened to the table (in my case a torsion box) between the existing 20x20 extrusions. In this image, the lighter coloured material is the two pieces of MDF I’m referring to.
Firstly, I have to securely fasten the X-Carve to the torsion box. As the top skin of the box is only 9mm, I’m using hollow wall anchors to do this. I made few brackets from 25mm aluminium angle on the X2 mill.
Holes drilled in the torsion box for the anchors.
and bracket installed.
There are two mounts at the front and rear of the X-Carve and one on each side. I still have to make a bracket to hole the centre extrusion down as it will likely lift with clamping.
Not shown are the 5 pieces of sail track that have been cut to length, drilled and counter sunk.
I’ll probably use the same anchors to hold the larger MDF pieces down to the torsion box and I’ll install some threaded inserts underneath these prices so the sacrificial board will have something to fasten to. I don’t like using wood screws directly in MDF, they don’t hold well and tend to raise up the material you’re screwing to.
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A bit more progress. First layer of MDF cut and test fitted. I need some more anchors before I can fasten this down. That means a trip to town (60km) so I may put this off until I have few other purchases to make, save on fuel.
A couple of (rough) coats of polyurethane to seal the MDF, it won’t be seen.
The newly cut MDF showing where the sail track will be fitted.
After thinking about it, I’ve added a few more anchors to stop the X-Carve lifting when cutting. With the original design, the tendency for the Z axis to lift when plunging, is offset by the fact the the bit is pushing against the spoil board which is in turn holding down the X-Carve. With my changes, the Z axis is pushing down on the spoil board which is no longer connected to the X-Carve. By securely fastening the X-Carve to the table, to which the spoil board is (or will be) firmly attached, lifting shouldn’t occur. The extra anchors will also help any flexing in the 20x20 extrusions as a result of clamping to the spoil board.
After a moderate amount of swearing, I have the first part of the sail track spoil board done.
6 hollow wall anchors to hole down each of the two pieces of MDF that form the base.
Screw for the anchors are counter-bored a fw mm below the top of the MDF.
Sail track is not screwed on as yet, I just need to work out the maximum width I can cut so when I surface the yet to be installed sacrificial MDF, there won’t be any part of it higher than the machined surface. That width will set the spacing of the t-track.
Here’s a hint, if you make a torsion box, make the top at least 18mm so you can screw things to it!
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Managed to find enough 18mm MDF to cut for the sacrificial top. I did manage to miscalculate the undercut I needed to make to clear the sail track. Still, it’s sacrificial right?
I have another full sheet (2400x1200mm) of 18mm MDF but it’s in the van and it’s raining so I’ll have to finish the rest later.
Still deciding on the best way to attach these pieces, threaded inserts look like a go at the moment. Need g-code for doing the drilling or at least marking where the holes will go.
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Looking Good
I would use 1/4"-20 threaded inserts and nylon bolts. Well, that’s what I’m going to be using anyways.
Plan your holes so that you can reverse the sacrificial boards 180 degrees and still use the same holes. This allows you to use more work space before resurfacing.
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Very nice!
This is how I want to do my build as well once I get the space and table setup. I plan on cutting through the table under one of the wasteboards so I can remove it and expose the hole through to the floor, allowing for end engraving of something long (maybe a cane head or to use a dovetail bit on the end of a box)
Excellent idea! I’ve got a bit over 8mm of clearance between the top of the sacrificial board and the sail track, more than enough for a couple of resurfacings…
A small backward step. I went into town yesterday to buy the screws to hold down the sacrificial MDF and ended up getting ones that were too short by about 2mm! I’ll have to go back today, a 120km round trip, to get the right ones 
Got the correct screws today, early trip into town. I now have the joy of screwing 72 of these into the spoil board…
Hi,
Question for down-under folks… X-Carve or XYZ-Carve?
Thanks!
-Philip
Gotta admit, I’d like to “buy local”, but Inventables have been so good to me, they’ve still got my loyalty…
Well I had a stack of makerslide and a few gecko controllers when Ben from 3dtek gave me a VERY good price on the bits I needed, it was a no-brainer.
Hi Geoff,
I’m having the same problem you’ve describe, but can’t seem to find the other thread you’re alluding to where the problem was resolved. Could you please point me in the right direction?
-edwin
