I'm developing a new metal cutting CNC – a CNC mill – and a strong base is always the very best method to start. Made from 200lbs of high strength concrete, in this video I construct the kinds to cast the concrete, then mix and put the concrete in.
As I stated in the video, the concrete is simply the sand/ cement blend you can get at the home center, however I augmented the strength by including additional portland cement.
The base is a fairly intricate shape with high sides and back, however open on the front for gain access to. The bed actions down at the back to form a sump for the coolant pump, keeping the cutting fluid inside the base.
No strengthening steel: strengthening is not required for this sort of casting that will be totally supported on a table. I did use a piece of high strength polyester fabric to "reinforce" the bed, but that remained in the "it can't harm" category and better than tossing the scrap of cloth in the garbage.
In the next video I'll strip the types and we will see how it turned out.
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I’m building a new metal cutting CNC – a CNC mill – and a solid base is always the best way to start. Made from 200lbs of high strength concrete, in this video I build the forms to cast the concrete, then mix and pour the concrete in.
As I said in the video, the concrete is just the sand / cement mix you can get at the home center, but I augmented the strength by adding extra portland cement.
The base is a fairly complex shape with high sides and back, but open on the front for access. The bed steps down at the back to form a sump for the coolant pump, keeping the cutting fluid inside the base.
No reinforcing steel: reinforcing is not needed for this kind of casting that will be fully supported on a table. I did use a piece of high strength polyester cloth to “reinforce” the bed, but that was in the “it can’t hurt” category and better than throwing the scrap of cloth in the garbage.
In the next video I’ll strip the forms and we will see how it turned out.
Thanks to you i have build myself many tools but you are wrong about wood glue and melamine i do it all the time this glue nowdays is artifishal not natural it will glue up that melamine like nothing
Love your work!
OK, so now we wait for part 2!
LOL definitely 😀
Should be next Sunday, barring any problems.
To reduce the pinching of the blade, you could also do the “flat” side cut first, then when you do the “edge” cutting, the waste piece will have less strength to close up.
For the plastic cutting, place a piece of plywood on top of the plastic to hold it down. If it slips too easy, put some “rubber” shelf liner under the plywood. Much faster and saves the digits.
You should have added a ratchet strap around the form, the brads do not have a large holding force and the weight of the concrete could have pushed out one of the sides.
I like your first suggestion, but hindsight always has better vision that in-the-moment foresight 🙂
A ratchet strap would have been belt over the suspenders and wouldn’t have made a difference for this – the yoke was strong enough. I’ll show where I should have beefed up the forms in the next video.
I’ve seen others take the blade off of a reciprocating saw to vibrate forms with, might be able to press it in to the back of your trowel and use it that way to agitate the concrete w/o stressing the form too much.
That’s good for a bigger pour, but this was small enough that the trowel worked perfectly – fast and easy, since it’s already in my hand.
No sé si por ahí tenéis bolsas de hebras de fibra de vidrio. Lo mezcla con el hormigón y le da mucha firmeza y fuera anti grietas . Saludos desde España
After the CNC is before the CNC 🙂
Let’s hope you don’t regret it not throwing some cheap reinforcements in the base.
I know I would have spent the 5 bucks or 10 minutes to find some scraps.
Of course you would.
I was so relieved when you added the cloth reinforcement. It was a great idea.
Nothing better then getting out of church, then being treated with a John Heisz video.
Always well done!
Ive always admired how you build the tools in your shop, really looking forward to see how this turns out. Thanks for sharing!!
aint watched your channel in a while. you look super well. ive seen people use 3d printer forms as concrete forms. you can even keep the plastic forms inplace, cuts down the dust etc.
I used to be a cabinet maker. At one place I worked we built cabinets primarily for schools, hospitals, and offices. Most of it built with melamine – we used a glue made for bonding melamine and porous wood materials, came in big ketchup/mustard type dispensers…I don’t remember the name of it. I think Titebond makes a glue for it also.
I use a glue that does stick – polyurethane construction adhesive
If, or when, you rebuild this I would recommend sealing the edges of the melamine. It absorbs a lot of water from the concrete mix and can swell. Rubbing wood glue over it works well.
I left out the part where I coated the endgrain of the particleboard with vaseline. It stopped the swelling and of course made it less sticky for the concrete.
You can always drill a hole and epoxy in that little plug you kicked out.
Hello John. I hope you are doing well. I always get an education watching your videos! I’m not a big CNC guy but I do enjoy seeing your creations. Look forward to part 2 of this build.
Thanks Bill 🙂
Next time on a concrete project, to overcome the water/cement ratio problem of a not-to-dry/not-to-wet mix, consider an admixture called a plasticizer or commonly referred to as a water reducer. It is used all the time in construction to achieve a very flowable mix that will get into all the “nooks and cranny’s” that might otherwise be a problem. Plasticizers are a polycarboxylate that work on the molecular level and help break down surface tension, allowing a flowable, more workable mix w/o adding excessive water. I think they are even available at the big box stores these days in the concrete section. In a pinch you can add some dishwashing soap to your water as they contain polycarboxylates as well.
Do you have something against shrinkage?
It’s looking great, John! 😃
Looking forward to the next steps!
Stay safe there with your family! 🖖😊
What a cliff-hanger!
Makes me want to go out side and mix a batch of concrete! Thanks for the vid, cheers!