home made epoxy granite cnc - part 4 - x axis 

Yes, wasn't too sure about that. And pretty happy when I opened the mold and saw that it worked out

@@joergbeigang think I'd have casted the plate "housing" with inserts, then bolted, glued and leveled with a thin layer of epoxy... Anyway, glad it worked 👍

Hardly practical.

@@hardcase1659 why not ?

@@dellosCao You don't really need that stiffness for 3D printing where there are no forces involved. You would just be wasting money tbh.

Definitely. But luckily it worked without as well. With this part I was a bit concerned...

@@joergbeigang Yes. Looks like it worked either way. Coming along nice!

@@joergbeigang would definitely recommend it, if you don't vibrate the bubbles out you end up having a lot of porosity. Would suck to spend all the work on it and then have it break because of that. It can be as easy as pushing a delta grinder or similar against the mould.

Actually I can't really remember anymore. Bought 3kg bottles. Not sure anymore if two or three. Got half a bottle left. Gelcoat was one tin maybe half a kg and release agent one bottle which is still almost full. Just go and buy a bottle of resin and do some test castings. After that you got a pretty good idea on the percentage of the resin in the mix and you can can easily calculate the total amount. Good luck with your build!

With the first piece I went to the shop of a friend and milled it. Because his shop is six hours drive away and I don't want to steal too much of his time I did the other two pieces by hand. With a granite plate and sand paper. Was quite a bit of an exercise, but didn't came out any worse then the milled ones. I'll show a bit of it in the next vid. And yes, feel free to copy :-)

No worries, I'm not rushing at all. Took plenty of time to prepare the parts for both molds, x and z. Then casted them shortly one after the other. My goal is to build a good machine I'm happy with and to learn a lot while doing it. That can't be done in a rush. But learning also results in doing tasks faster and better the second or third time. Always happy to read your comments!

The surface finish is like that because of the gel coat

Ah okay. So probably that gel coat also is a kind of protective cover against coolants right?

The main reason I used it is to protect the release agent. I was afraid that the sand and gravel could scratch it away and it would all stick to the mold.

The rails are mounted first. With the rails is not much room for adjustment. The two plates are going to be screwed together with quite a few screws. The screws in the holes will have enough play to adjust the x axis perpendicular to the y axis. Making x and y parallel to each other will be a bigger problem. The perfect way would adjust it just by lapping one metal plate, but I'm afraid I got to do some shimming too.

You could probably adjust the angle of the z-axis to compensate for this. Then the x-axis and the y-axis dont have to be perfectly parallel

Thanks. It's made by proxxon.

I mixed resin and hardener first, then I poured it in an empty bucket and mixed it there by putting step by step more sand gravel mix in. All after extensive testing to find a good mix ratio

@@joergbeigang Thank you very much, I have my cnc machine and it is made of cast iron but it has very thin and hollow parts of the machine, it is where the vibration and resonance occurs, my intention is to fill with the granite epoxy, what I have doubt is if granite epoxy will adhere to the cast iron frame, very grateful for responder

There are some videos on RU-vid of guys who did exactly that. Maybe ask them if it's worth the effort in the end. For example here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-k1r36ykaRLA.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Upeu0kteUs0.html I'm sure if you start digging, there are plenty more

On the first part I used 15 percent. Came out slightly bended. 3/10 mm on 450 mm length. On the other parts I used 12 percent and they came out pretty good. The base of the z axis didn't need any machining. Was done in one hour lapping by hand. It depends a lot on the sand gravel mixture, and the kind of epoxy. But 20 percent sounds a lot to me...

@@joergbeigang I see - 0.3MM is quite a lot over 450MM.. hmm. I saw this video which shows that 20% epoxy seems to offer more rigidity (ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-bcEPoZTAlcA.html). The other thing is just the surface finish is easier to get perfect with more epoxy judging by what I've seen. Is there a problem with machining the 0.3MM down afterwards or are parts under too much stress? Thanks

Can't tell about the stress, but I simply milled it flat. I made some tests before, from 10 to 17 percent. From 15 percent on there was quite a bit of a layer of resin on the top. I made more of less identical parts and I couldn't really measure any difference in stiffness with the strictly non scientific tests made. In the end of the first vid of this series you can see the bended one under the straight edge.

@@joergbeigang Thank you! Look forward to seeing the rest of your build :)

That's pretty hard to tell. Just the actual work might be about three to four hours for the metal parts, maybe one hour for the chip board cutting and drilling, an other hour for the reinforcement, two hours assembly of the mold, half an hour for the gel coat and a good hour for the actual casting. But endless hours went into the planning and the cad. Those i can't count...

No, still a bit of work. Finished the steel frame where everything is sitting on. Now I'm taking my time for adjusting everything. I guess in about two weeks I'll have a new vid with the progress

I love the whole reef calendar. Sadly my source for getting them dried out a few years back

You're right, didn't really show this. The bearing blocks are mounted on a aluminum plate, that's attached with screws to the aluminum surface on the part I made in this vid. Getting it square was a proper pain in the bum. Gave up at one point and started over again the next day. Just not something that's interesting in a video. Loosening and tightening screws and knocking with a hammer for hours...

I think he left enough possibilities for adjusting all the parts relative to eachother. My biggest concern is the planarity of the guide mounting surfaces tho. Anyway, you don't know the application the creator of this video has in mind. No need to talk him down.