Actually I used the milling machine of a friend only for the first part (mainly because it's six hours drive to get there). X and Z I lapped by hand. Took a while, but the result was better.

That's difficult to answer for me. I'm by no means an expert for epoxy granite. I did a few tests and then I build myself a machine. So my experience is limited. I can share some observations I made. But in the end you gotta make some tests by yourself, with your epoxy, your sand and gravel. Epoxy is shrinking when hardening. More epoxy in the mixture means more shrinkage but it's easier to work with, less means less shrinkage but from one point on you need vibration to get the air out. It all depends on the volume.It needs a certain volume to work well, also the shape is important. As closer the proportions are getting to a sphere as lower is the resonance frequency. Long and skinny is bad (figured that with my z-axis). But the shape in your case is given anyways, and extrudes sounds like long and skinny. The question is what is your goal here. Stiffness or damping? It’s really hard to tell, for damping just filling with sand could do the job, for stiffness you need volume. But I can be totally wrong here. Just go and buy some epoxy, get some really dry sand and start playing around to get a feeling for it. Fill an extrude and compare it to an empty one or one filled with sand. Deflection is easy to measure and how “silent” it is you’re getting a good idea when hitting it with your palm or a soft hammer.

@@joergbeigang okay thank you for taking time to give me such good advices I will do some experience so . And yeah I want to fill it for no resonance and for the stiffness a don’t if it’s useful or if my machine will do the job like that …

So far it's all good with the linear rails

@@joergbeigang thank you bro

Can't remember, was a few years back now. Just do some tests, that's what I did before. Most important it's got to be very dry.

Good point. I can understand that it's not always that easy to follow, also because I only recorded a small part of the actual work and often I was working around problems which are not that obvious. Making a summary video is of course a good idea, but it's also time consuming. And time is the crucial point here. I'm pretty busy at work plus I'm also renovating a house I recently bought. But it's definitely on my to do list.

the nipples were mounted on the linear bearings, I replaced them there with the quick release fittings for the tubes. I bought all that stuff online, could have been ebay, can't really remember. If you google for pneumatic tube and quick release you'll find plenty.

Hi, I used some liquid, wax based release agent. You can find it everywhere where they're selling materials for composite

@@joergbeigang Thank you

they are Chinese CHTR

@@joergbeigang Thank you

sure, my first name at goob.de

That's because I can't really work with bigger parts of steel (not having the machines for it), and aluminum is a terrible choice concerning vibrations. That's why I made it of mineral cast. I read about a minimal material thickness with mineral cast, and I did not have any experience with this material, so I preferred to stay on the safe side and make it a little more massive.

@@joergbeigang HI Joerg, thank you very much for your reply, I am designing mine at the time, this is why I am asking questions.. cool that you took the time to reply, I really appreciate

Happy you liked it. Yes, I've tried. Mild steel with a 3mm end mill is working. But it starts to sound bad. I think the HF spindle is not the right choice for steel. With a low rpm spindle it might be a different story, but not with that spindle. It's just not having any torque in lower rpm, and high rpm requires a adequate feed and then the forces are just too high for this little machine.

I'm about to start building a cnc lathe and I was planing to do a very similar thing like you did with the molds. I'm wondering how's your machine holding up? Were there any issues with casting the epoxy granite, or with the flatness 9f the machine bed?

For oil. Without them it would be pretty hard to reach the bearings when the machine is assembled.

sure, they are x 600, y 450 and z 350mm x 20mm. The length of the ball screws are according to the travel of each axis. The rails are Chinese CHTR and about the ball screws I got actually no idea what brand they might be. And the travel is 330mm, 235mm and 180mm.

@@joergbeigang Thank you so much! Could you also reveal how it turned out in the long run? Are you still using it? I think youve done something incredible here and people are definetely curious to hows it going !

​@@piotrilja9211 Actually I had my whole workshop in a storage for two years. Had to temporary leave the country for some family reason and just last month I moved everything in a new garage. So I used it less then planned in the last years. But used it enough to figure out a few things. First of all I'm not so happy with the 2KW spindle. It just doesn't have enough torque in the speeds where you'd like it to have torque, The assembly of the Z axis is made of aluminum which isn't the best when it comes to vibrations, and I should have made the z axis longer, at least 100mm. Especially with a vise and a little longer end mill it's getting quite tight. And a few things I overcomplicated design wise. For sure the wheels where it's on are way too flimsy. One wheel broke when moving it off the trailer and now I got to find a way to replace it. Right now I'm too busy to find some time to take care of it, but I'm planning some project for the winter month. Till then I'm trying to get it all in good running condition again.

They're just some Maya shading networks simulating the alias shaders