Do you mean like a nail punch or something else ?
Thread a bolt into it and knock it through.
Or use anything that will fit in the against the top.
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I use a 1/4" flat punch but as Neil suggested thread a bolt in and tap it with a hammer and it will fall right out.
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One thing to note here is that on previous models of Shapeokos folks used to install a supplementary MDF wasteboard on top of the MDF bed because…while the MDF end could have been used as a sacrificial wasteboard, replacing it was not easy nor convenient (you would basically have to disassemble the machine back then). So it made a lot of sense to ADD a wasteboard that could be easily replaced when damaged. A number of videos you see might be from that period of time when it made sense, and might be from folks who kept that old habit.
Now, with the latest generation of Shapeoko and their hybrid table, I would argue that the situation is different: the MDF slats that go on the hybrid table slots are designed to be easily replaceable without impacting the machine’s structural integrity/squaring/tuning, so there is really no need for a supplementary wasteboard on top of them. This is especially true if you learn to be a little careful about your depth settings. I now very often use “stock bottom” as the Z zero reference, which pretty much guarantees that the toolpaths will barely scratch the surface of the slats when doing full depth profile cuts. Anyway, I thought I would mention that in case that can simplify things for you by not having to worry about installing a supplementary wasteboard.
We have literally all been there, it’s part of the CNC addiction 
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@Julien, isn’t it kind of a pain in the butt to completely surface all the slats on the hybrid table? Aka, if you want all the slats to be flat from front edge to back edge and left edge to right edge and not just a flattened recess in the cuttable area? The last I saw, the procedure involved having to keep swapping the slats around to get all of the parts flattened. At that point, I wasn’t even convinced you’d end up with something that was truly flat due to slight differences in where and how the slats are finally screwed down.
FWIW, I’ve never tried to flatten the slats (I use SMW fixture plates and a sacrificial wasteboard on top of that if I need it for something specific) but when I first received the machine I was relunctant to do flatten the slats in the hybrid table because of what I thought was the complexity of that process.
I did this once. And I did have to make an adjustment in Z to get the far left & right areas outside of the cut area. Front to back worked well. Although the screws holding the slats are not evenly spaced ???
I’ll be doing it again today/tomorrow, I think I’ll cut a relief around the outside of the cut area 1/8 - 1/4" deep. I use a 3" sanding disc to flatten the spoilboard, taking maybe 0.005" so that should last quite a while.
I thought of just adding a secondary spoilboard on top, but then I lose that much Z space, and also the T-slots.
Well, there is a 30-day warranty — that said, yeah, I just nicked one of mine the other day — in parallel to how I describe my truck:
It’s a spoilboard, I expect it to get scratched up when working
It’s not something I would enjoy doing every week, but honestly it’s still relatively simple
- surface the bottom half of the slats (except the two outer ones)
- flip them and rerun the surfacing job to do the other half
- if you really want to squeeze every last inch of travel/work area, swap the two middle slats with the two outers ones and repeat 1 and 2 on the two center slats only, then swapped them back to their outer slot.
On a XXL I don’t even bother, I just surface them to a smaller thickness and you will only have to do this once (they just won’t support your stock, but the work area loss on an XXL is minimal)
As I mentioned, since I’ve been using the “zeroing on stock bottom” method, I rarely ever cut into the slats anyway, so I have not had to resurface in the last 6 months.
Like Tod mentions there is the matter of losing some Z clearance, and losing the ability to use T-slots. But hey, the beauty of those machines is that everyone can customize their setup at will very easily, so using a supplementary wasteboard is an option for sure. I was trying to convey to @cog that it’s not a mandatory part of the setup now, while it pretty much used to be. I also get that while one is in the process of learning CNC, it’s a good safety net to have to feel at ease.
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As an alternative, you can surface down the outer slats and that portion of the inner slats so that they are level w/ the Hybrid T-track, or just a bit higher:
or see what I did on my XL:
Thanks for the explanation. It doesn’t sound too bad but definitely sounded more intimidating when I was brand new to CNCing. I’m still not convinced you end up perfectly flat but since you surface the cutting area in its final position that’s probably not critical that the outer parts are flat. And that’s a good idea to surface the outer slats lower!
Also, I definitely agree with the zero on bottom. More people should do that! In the dozen or so jobs I’ve run on the sacrificial wasteboard using double sided tape, I haven’t even cut all the way through the tape yet let alone into the wasteboard!
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Chris, it may not be as convenient as a complete spoilboard, but for the last couple of months I’ve been using a bunch of strips of 1/8" plywood (about 1"x12") arranged loosely under my workpieces (on top of the MDF hybrid table). The clamping pressure provides enough friction that I’ve had no problem with them shifting. As they get torn up, I can just make more. Anyhow, it’s another option.
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Is this what I should be getting to spray it with to seal it ? https://www.lowes.com/pd/Minwax-Helmsman-11-5-fl-oz-Oil-based-Varnish/999913673
Pick any moisture-resistant finish you are comfortable applying/using.
I used a spray spar urethane.
Should it be oil based or water based ?
What about polyurethane ?
I have no idea how any of this stuff reacts on MDF
Water based will swell your mdf more than oil based. Oil based will soak in better but if you have any scraps try it out before applying it to your spoilboard. Oil based like polyurethane and the spar urethane are oil based and as the urethane name implies is also a plastic. Thinks like polycrylic is waterbased and will penetrate but tends to swell and raise grain. Now MDF does not have grain but it will swell more than the oil based.
I do not put anything on my spoilboard but I am not machining metal with any lubricants. So mileage varies depending on what you will be machining. I live in East Texas where the humidity is 80% most days. So it is hot and humid. Unless you live by the sea humidity may or may not effect your spoilboard because mdf is a mix of sawdust and glue. There are different types of mdf and some have more sawdust and some have more glue. There is no specifications for what you get.
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I have a question for the group. If I seal my MDF waste board, will I be causing issues?
Mounting holes “Screw”, when I attach the board, won’t I be scaring the protected surface allowing moisture an access point? When I cut into the MDF, should I follow that up with a spray of sealer?
Some of our climates are not helpful to the MDF. That is why I call it a waste board. I use it up, waste it, then replace when used up.
Will sealing it make it last longer? Will the extra steps used to re-protect it save us time in the long run?
Not trying to be obnoxious. Like anyone if I can save a dollar, I will try.
If you are cutting into it constantly, as on an MDF filler strip on the Hybrid T-track, or a spoilboard added to an SO3, then no, it probably doesn’t help to seal it — if you need additional stability in something you are constantly cutting into the solution is to use a more stable material such as cellular PVC.
Sealing only makes sense in the instance of a piece which is intended to last — the baseplate on an SO3, or the MDF Filler strips on the Hybrid T-track if one will be mounting a spoilboard on top of them.
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Thanks, Will
I almost swallowed my gum when I saw “Sealing” ha ha ha
Stick with what I am doing
Ok so I finally got the time between a bunch of medical appointments to work on this again and I wanted to update my progress, I bolted down the spoilboard until it was flat against the top of my shapeokos original spoilboard slats using the slots underneath. (thank you for this suggestion Will)
I refinished the top using a Whiteside Fly cutter this time and it did a much better job than the McFly Cutter. I was like a night and day difference. The Whiteside Fly Cutter did not leave high grooves like the McFly did between passes and I only had to lightly sand it briefly over the top to get it totally smooth.
The pocket in progress is with the Whiteside Flycutter. Outside of that is the original surface the McFly bit left. There is a huge noticeable difference between the two.
I did get the Edge Technology Mini Pro Tram for my Shapeoko and plan on tramming it soon but I do not think it is far off it is off at all based on how the Whiteside Fly Cutter did.
When I go to replace this spoilboard I will do as you suggested gdon and Neil to extract the t-nuts and seal it.
Thank you Julien for the explanation of how to do the slats and the history of the machines , and the zeroing on stock bottom method (I will have to look more into that.
If I missed anyone thank you to you as well. Appreciate the help
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