nice job!! I used to make custom parts for pinball machines, video games, pool tables etc, it will help greatly if you wet down that sandpaper in warm water and just a drop of dish soap as you are deforming it, it will take the shape better and last a bit longer.
If you cut the abrasive sheet from the rear (paper side up, grit on the cutting surface) your knife will stay sharper longer and you will get a better cut
pro tip, for lasercutting layers. give them a spine. meaning each layer gets a rectangular hole in with the thickness of the material as side a. and you cut out a rectangle with side b as one side and the overall hight of your build as the other. than you can stick that spine through all of the holes. that way the layers are perfectly alined.
@@FraensEngineering I did not find the comment you refer to. could you add the link? in you do not know how this works, the link directly to a comment is under the time stamp (right klick, copy link address)
@@FraensEngineering well, than you can see this comment as a refinement of that Idea, in that you also cut out the spine. in my library alinement holes and spine are a standard joint (even though that is not stricktly speaking a point) so it always fits perfectly.
Love this. So satisfying seeing the surface of that wood shine. Modularity of the tool heads is so cool. That concave surface must be important. I've cut down finishing times by adjusting seams to 'rear' then orienting parts to put seams safely away from contact points.
the concavity is irrelevant other than it should be more extreme than the convexity of the surface being ground. you want the contact patch to be at the outer edge. look at commercial units and theyre always more oriented to "rings" or cups, much like the hole saws were...
I'm happy to get a comment from you ;-) I know all your videos and your website and have been a long time subscriber. I'm glad you like my machine. I would like to make stone balls with it next. However, I still lack the right tools to make the raw balls.
Since you've been bothered with 3D printing, at the first stage it was worth making a mini wood lathe. The motor rotates the workpiece. The cutter has two degrees of freedom: it can rotate radially and move perpendicular to the axis of rotation.
I like how you've done this, it's satisfying to see the 120 degree angles and geometry of your parts. I made some wooden spheres entirely by hand during COVID times. I made a cube and used a handsaw and plane to remove the corners, then made a 'hole saw' by filing teeth into the end of a steel IKEA table leg. I held that in a vice then randomly scraped my cube on the teeth (wearing thick gloves). That got the basic sphere then I used sandpaper held on the open end of a jam jar to do the polishing. They ended up really good. I think it's interesting that random movements produce such a perfectly even and symmetrical shape.
Hi, that sounds like a lot of work. The idea with the table leg is brilliant. How many hours of work must that have been? What do you do with these balls? Are they purely for decoration?
@@FraensEngineering The table leg worked well, I have coarse teeth on one end and finer teeth on the other end. Making a sphere takes me about 5 hours from cube to about 2000 grit sanded. So far I just have them as decoration and presents for my family. I'll make more when I have some more interesting pieces of wood. Great idea of yours with the plywood discs glued together!
@@FraensEngineeringI wonder if a very large rock tumbler could do the trick, after receiving rocks crushed uniformly by a large rock crusher. I'm interested in this idea for forming curved ends of compression rods for tensegrity construction, so the ropes or metal cables will smoothly bend around a curve, rather than be cut over time by wrapping around a harsh hole or pipe end. Maybe if end-plugs compression rods are made of stronger and tougher material than the rod, it will allow for more certain and predictable strength. ...Perhaps even better if these spheres had a curved end-mill drill into them on either side, 4 times, connecting in the middle, so cable could be looped through the holes.
I don't quite understand what you mean, but the tensegrity construction looks very interesting. I have been working on a vibration tumbler with magnetic drive for about 2 months. It works really well and I'm currently polishing my second batch.
> make gemstone spheres! Thought the same thing ... but I don't see that the extra hardware (steel and diamond abrasives) are required at each stage. Required at some point? Some yes, some not at all. Here's how I see it (corrections and additions are appreciated!); * As long as the mechanism can support the heavier material, that design is fine. If it can't, making a more robust mechanism, while keeping the general design, should reach the intended goal. * There will be a change at each stage of the abrasives that are used. Saw a tree down with a chainsaw? Good. Use the same chain saw to make a thin walled bowl -- from the same wood? Stupid, even if possible on a dare. Using the right abrasive at each stage will save time/effort. Ignoring this while making new machines to make things faster is not going to make things faster or reduce effort required to make things faster. (Note: At the same or better quality level.) * As long as the abrasives used are efficient at the stage of carving (or polishing), they are suitable at that stage. Unless the sphere is a one-off, there's a gap between what is possible and what is efficient. * For most (?!) of the polishing stage, diamond abrasives are not required. Here's why: The Mohs hardness scale should be included to see if the abrasive material at each stage (not just polishing) would be effective. Ignoring that would likely waste time and materials; even tool steel requires sharpening and/or replacement.
if you're going to use a laser cutter to cut out disks you should probably cut a hole in the center of each to glue a dowel in the middle. it should keep them nice and uniform so you dont have to grind away as much!
ok at 3:50:00 how is your parts holding up? this is good, but curious on the friction heat from the sandpaper to the pressure pushing against the sandpaper and wood. did the part have any deformation or heat issues. or is it still holding up. Also, your machine should be leaning or standing up where the dust will escape at the y opening for them to fall out. just a thought
Basically, you're right. However, it is also possible to form a relatively coarse ball. Of course, it is easier to grind an already clean ball further.
I'd like to find a good method to measure how spherical they are, I haven't got round to it yet but I think the biggest deviation is less than half a millimetre in a sphere of 70 mm diameter. Would be nice to compare 😊
Just found your channel and this build. Very nice! Definitely gonna have to build one. Is the size of ball made somehow adjustable? Or what size or range balls are made?
@@FraensEngineering Loved the video. A unit I saw for rock had diamond hole saws the same way you did. The big problem is you will need to mitigate abrasive dust and water so the motors may need work.
I need a spear for my table it goes at the bottom under my 6+2 = 8 with extra leaf put in to hold the table stable, underneath stabilizing the table from unnecessary movement...
You have to plan for a few hours. However, you can leave the machine to run on its own. You should only check from time to time whether the motors are still at a comfortable temperature.
That's exactly my plan. However, it is currently failing due to a rough stone. Unfortunately, I don't have the right tools to make a rough cut. Do you have any idea where I could get a stone from?
th-cam.com/video/Xu5X6UOAijw/w-d-xo.htmlsi=ZLLCyWQz8CnI46J5 This with your design would make fast work. As for the stone I am a professional glazer I have some ideas to share
End product looks really amazing. IDK how you could use it for further utility, but I bet they would make great juggling balls, artistic features, light fixtures, etc. Extremely cool. Do you think you could grind a clear plastic down so you have a clear transparent wizard orb?
I'm most impressed with the shear amount of abuse it's able to take I haven't been this impressed since I stepped out of the shower dripping wet (sorry for that visual). Thank you for the video!
I saw this idea in rocks sphere manufacturing. If you have good drill press you can try using sphere cutters from china. Biggest I buy was for 50mm dia spheres. Or use this method of preparing sphere blanks for sanding th-cam.com/video/JB0x5v5WUYE/w-d-xo.html
Interesting machine, however overly complex... You do realize that any object left to bounce on a flat surface will inevitably tend towards a sphere ? All you need is a moving abrasive flat surface, like a disc from an angle grinder, and a way to loosely constrain the wooden piece. Then you can even start with a cube and it will grind itself into a sphere...
@@FraensEngineering I'll check and post but here is maybe a more practical description of such an implementation: Take a tube 50cm long, 15cm diameter. Mount vertically. The top open end is where you drop the block of wood (say 5cm long) to be rounded. On the bottom end, place an angle grinder with a sanding disc, so that the disc essentially covers the opening. drop a block of wood in the tube while the grinder is running. The important part is that the wood piece should bounce around and roll randomly, if it gets caught, it will just grind a flat. So chopping off each corner of the cube to grind will help.
It's great that it works like this. That would be an excellent method for preforming the balls. With the Sphere machine you can then finish grinding and polishing them.
@@FraensEngineering yes, but you can also polish as long as the disc has very fine abrasive, or a felt pad with polishing paste ( and the cylinder interior could also be felt lined and polishing paste loaded )
@@bschwand yep. or mount an orbital grinder above a flat board with sanding sheet, and a spacer in between with a hole cut through to shove the item in. the orbital motion helps... some sort of feeder so you can adjust the gap between sanding surfaces... pretty well much how ball bearings are made, though they do start with a forged, "close to ball shaped" lump of steel. this approach, using the three cutters, is more trended towards the final polishing process, not rapid material removal.
Anybody wants to make their own, 4 would have been better than 3. Because the real world is 3D and not 2D. It's obvious when he had to hold it in because it was falling out.
I don't think this is the way you describe it. Professional ball machines work exactly according to this principle. I only had to hold the ball in place because the ball was very inaccurately pre-cut.
Very interesting ideas ! But it's either unwillingly wrong or plainly clickbait: it should read something along the lines of "3D printed sphere *polishing* machine" the way it's worded gives us the impressing that the machine actually makes the spheres.
@@FraensEngineering T nuts are designed to be used under compression, not under tension. You've installed them all under tension by putting them on the the same side of the board as their bolts. The result is that, under low to modest load, the nuts will come loose (pop out of the board). They cannot typically support more than a few pounds of force in this configuration. If you had instead placed the nuts on the bottom of the board (opposite to the bolts, as they're designed to be used), then the nuts would be capable of supporting orders of magnitude more load, and it did likely contribute to a stiffer mechanism overall. Each nut would then be able to support over a hundred pounds of force.
@@FraensEngineering no, I mean the T nuts you pounded into the wood. i.e. the "wooden T-nuts" that I said in my first comment. Search for "t-nuts for wood" on Google and you'll know exactly what I'm talking about.
0:42 that music sync is insane
It’s not often that I see a brand new machine concept. I’m impressed with the ingenuity.
It took a lot of balls to make this video.
OK. Now that's humor
It took a lot of video to make these balls. 😜
touché
Does it cut the balls?
with that, I'm not going to ruin your 69 likes there!
3:27 - step 1. Start with a sphere...
The way the video is edited makes the hole process look really good it was a joy to watch it! thank you!👍
nice job!! I used to make custom parts for pinball machines, video games, pool tables etc, it will help greatly if you wet down that sandpaper in warm water and just a drop of dish soap as you are deforming it, it will take the shape better and last a bit longer.
That's a really good trick. I wouldn't have thought of that. Thank you very much
If you cut the abrasive sheet from the rear (paper side up, grit on the cutting surface) your knife will stay sharper longer and you will get a better cut
That's exactly what I did after the knife immediately became blunt.
pro tip, for lasercutting layers. give them a spine.
meaning each layer gets a rectangular hole in with the thickness of the material as side a.
and you cut out a rectangle with side b as one side and the overall hight of your build as the other.
than you can stick that spine through all of the holes. that way the layers are perfectly alined.
A similar idea has already come up in the comments. Thanks anyway ;-)
@@FraensEngineering I did not find the comment you refer to. could you add the link?
in you do not know how this works, the link directly to a comment is under the time stamp
(right klick, copy link address)
It was a hole in the middle that was used to align the disk. Unfortunately, I can't find the comment on the fly.
@@FraensEngineering well, than you can see this comment as a refinement of that Idea, in that you also cut out the spine.
in my library alinement holes and spine are a standard joint (even though that is not stricktly speaking a point)
so it always fits perfectly.
Love this. So satisfying seeing the surface of that wood shine. Modularity of the tool heads is so cool. That concave surface must be important. I've cut down finishing times by adjusting seams to 'rear' then orienting parts to put seams safely away from contact points.
the concavity is irrelevant other than it should be more extreme than the convexity of the surface being ground. you want the contact patch to be at the outer edge.
look at commercial units and theyre always more oriented to "rings" or cups, much like the hole saws were...
This is amazing! I've been looking for this exact machine!
I'm happy to get a comment from you ;-) I know all your videos and your website and have been a long time subscriber.
I'm glad you like my machine. I would like to make stone balls with it next. However, I still lack the right tools to make the raw balls.
Since you've been bothered with 3D printing, at the first stage it was worth making a mini wood lathe. The motor rotates the workpiece. The cutter has two degrees of freedom: it can rotate radially and move perpendicular to the axis of rotation.
I like how you've done this, it's satisfying to see the 120 degree angles and geometry of your parts. I made some wooden spheres entirely by hand during COVID times. I made a cube and used a handsaw and plane to remove the corners, then made a 'hole saw' by filing teeth into the end of a steel IKEA table leg. I held that in a vice then randomly scraped my cube on the teeth (wearing thick gloves). That got the basic sphere then I used sandpaper held on the open end of a jam jar to do the polishing. They ended up really good. I think it's interesting that random movements produce such a perfectly even and symmetrical shape.
Hi, that sounds like a lot of work. The idea with the table leg is brilliant. How many hours of work must that have been? What do you do with these balls? Are they purely for decoration?
@@FraensEngineering The table leg worked well, I have coarse teeth on one end and finer teeth on the other end. Making a sphere takes me about 5 hours from cube to about 2000 grit sanded. So far I just have them as decoration and presents for my family. I'll make more when I have some more interesting pieces of wood. Great idea of yours with the plywood discs glued together!
"Tell me you're an engineer without telling me you're an engineer"
Well rounded idea
"You have nothing to sphere but sphere itself..."
Dude.. you did it again! Amazing machine and video (and music! 8) and thanks again for sharing your work ❤ 🇳🇱
Thank you for the nice comment ;-)
The beauty of genius.
Cool, now make it in steel, with diamond abrasive, and make gemstone spheres!
Stone balls would be the next step. I plan to test it. However, the rough cut is still a problem.
@@FraensEngineering Fette Flex?
@@FraensEngineeringI wonder if a very large rock tumbler could do the trick, after receiving rocks crushed uniformly by a large rock crusher. I'm interested in this idea for forming curved ends of compression rods for tensegrity construction, so the ropes or metal cables will smoothly bend around a curve, rather than be cut over time by wrapping around a harsh hole or pipe end. Maybe if end-plugs compression rods are made of stronger and tougher material than the rod, it will allow for more certain and predictable strength.
...Perhaps even better if these spheres had a curved end-mill drill into them on either side, 4 times, connecting in the middle, so cable could be looped through the holes.
I don't quite understand what you mean, but the tensegrity construction looks very interesting. I have been working on a vibration tumbler with magnetic drive for about 2 months. It works really well and I'm currently polishing my second batch.
> make gemstone spheres!
Thought the same thing ... but I don't see that the extra hardware (steel and diamond abrasives) are required at each stage. Required at some point? Some yes, some not at all.
Here's how I see it (corrections and additions are appreciated!);
* As long as the mechanism can support the heavier material, that design is fine.
If it can't, making a more robust mechanism, while keeping the general design, should reach the intended goal.
* There will be a change at each stage of the abrasives that are used.
Saw a tree down with a chainsaw? Good. Use the same chain saw to make a thin walled bowl -- from the same wood? Stupid, even if possible on a dare. Using the right abrasive at each stage will save time/effort. Ignoring this while making new machines to make things faster is not going to make things faster or reduce effort required to make things faster. (Note: At the same or better quality level.)
* As long as the abrasives used are efficient at the stage of carving (or polishing), they are suitable at that stage.
Unless the sphere is a one-off, there's a gap between what is possible and what is efficient.
* For most (?!) of the polishing stage, diamond abrasives are not required.
Here's why: The Mohs hardness scale should be included to see if the abrasive material at each stage (not just polishing) would be effective. Ignoring that would likely waste time and materials; even tool steel requires sharpening and/or replacement.
Try installing flap discs for an angle grinder
That's a great idea
if you're going to use a laser cutter to cut out disks you should probably cut a hole in the center of each to glue a dowel in the middle. it should keep them nice and uniform so you dont have to grind away as much!
I'm pleased that so many good ideas have already come together here in the comments. Thank you very much.
I wondered who would get around to making one of these.
Someone who likes to polish wooden balls.
That one ball @7:33 has a literal Pegasus coming out of the clouds in it. Or a dragon. Either way metal as fuck for wood.
ok at 3:50:00 how is your parts holding up? this is good, but curious on the friction heat from the sandpaper to the pressure pushing against the sandpaper and wood. did the part have any deformation or heat issues. or is it still holding up. Also, your machine should be leaning or standing up where the dust will escape at the y opening for them to fall out. just a thought
The sandpaper heats up slightly. But nowhere near enough to damage the 3D printed parts.
That Reese going crazy bro
What size 3d printer bed is required? Can a a1 mini print the parts off? Its a 180mmx180mmx180mm bed size
Great build and great music. I usually hate vids that don't have talking in them, but this was awesome.
i think this technique is more suited to refining a sphere than creating a sphere from rough stock
Basically, you're right. However, it is also possible to form a relatively coarse ball. Of course, it is easier to grind an already clean ball further.
Nice balls
I'd like to find a good method to measure how spherical they are, I haven't got round to it yet but I think the biggest deviation is less than half a millimetre in a sphere of 70 mm diameter. Would be nice to compare 😊
I am currently grinding a sphere that is 3D pre-printed. I will try to measure the diameter. However, the ball has a diameter of 100mm.
Very impressive
Help i now have the innate urge to go and make this but its three am on a sunday
I can understand that. It is very satisfying to grind balls. It's 11 o'clock in the morning on a Sunday ;-)
I always polish my ball at that hour
💥💥💥💥, Can I have all the parts in detail?
www.etsy.com/at/listing/1661691704/3d-printed-sphere-machine?click_key=3136a969d67a05485fee2425bf9ef266eb4d81e1%3A1661691704&click_sum=a706b7d8&ref=shop_home_active_13&crt=1
Just found your channel and this build.
Very nice! Definitely gonna have to build one. Is the size of ball made somehow adjustable? Or what size or range balls are made?
Hi, the size can be adjusted by the distance between the individual grinding heads. I have ground balls up to about 100mm in diameter.
Yea, because any time I see Crocks in a video with power tools I know I'm in for a high quality video.
cool video!
Seeing you have a lathe could it drive one of the sander heads while the two others are non driven sanding heads?
Very nice!
Ah yes, making a sphere from a sphere. the old pass time of redundancy.
You need a blank. The machine then grinds the ball into a perfect ball. But yes: two are better than one ;-)
I used to have a neighbor who had something similar for stone. Do you think this could be modified to make stone spheres?
For stone balls, I'd have something. Just an idea. However, I'm still struggling with the rough cutting of the spheres.
@@FraensEngineering Loved the video. A unit I saw for rock had diamond hole saws the same way you did. The big problem is you will need to mitigate abrasive dust and water so the motors may need work.
I need a spear for my table it goes at the bottom under my 6+2 = 8 with extra leaf put in to hold the table stable, underneath stabilizing the table from unnecessary movement...
I don't understand what you mean.
The moment i have access to a 3d printer im gonna try this for stone spheres.
I'm just waiting for someone to test it. Please report when the time comes ;-)
@@FraensEngineering I'll be sure to.
I am here before the 1 million view mark!
1 million... that's still a long, hard road ahead. I don't think I'll ever reach that ;-)
@@FraensEngineering I have faith! Subbed!
First song reminds me of GTA 4, not sure why. That aside, the results are impressive! Very, very cool build.
Yes... those were the days ;-)
would this work for rocks with diamond abrasives
Unfortunately, I have not yet been able to test this. Unfortunately, I don't have any diamond grinding tools.
great project. sand dust clogged paper less effective, you may want to adress this issue
Can you describe in more detail what you mean?
@@FraensEngineering for example @5:17. if the dust remains in the sandpaper it becoma less effective. try dust extractor such as vacuum.
Have you considered spinning the rough cut on a lathe?
Yes, I have. But I didn't want to contaminate my lathe with wood dust.
如果做成4個
也就是把本來3個往下移 再加1個在正上方 會不會更順暢?
No, three are enough. You just have to place them at the right angle.
The comment below is probably the bast thing I have seen all day!
That's neat. How long did it take for the second one to run?
You have to plan for a few hours. However, you can leave the machine to run on its own. You should only check from time to time whether the motors are still at a comfortable temperature.
can you design one that can do rocks?
That's exactly my plan. However, it is currently failing due to a rough stone. Unfortunately, I don't have the right tools to make a rough cut. Do you have any idea where I could get a stone from?
@@FraensEngineeringmaybe ebay or a rock supplier for landscaping. I live in Colorado and there are rocks everywhere.
@@FraensEngineeringhammer and chisel?
Aawweessoommee!👏🏻👏🏻👏🏻👏🏻👏🏻🥰🥰🥰💓💓💕💞💛💛💗💗😍😍💖💖❤️
This is how pal spheres are made
I really like your design as a finishing tool not so much for a rough our, seems it would destroy the tool very shortly .Still as I said nice work.
I am testing whether I can grind stone Sphere
@@FraensEngineering Really?
But it will still take some time. A raw sphere has been molded for the time being.
How about a finer tool hole drill cutting first from 90 degrees latitude and longitude in a cross section then use your neat tool?
th-cam.com/video/Xu5X6UOAijw/w-d-xo.htmlsi=ZLLCyWQz8CnI46J5
This with your design would make fast work. As for the stone I am a professional glazer I have some ideas to share
End product looks really amazing.
IDK how you could use it for further utility, but I bet they would make great juggling balls, artistic features, light fixtures, etc. Extremely cool. Do you think you could grind a clear plastic down so you have a clear transparent wizard orb?
You could try to print a ball out of transparent filament and grind it. Should work I think.
I'm most impressed with the shear amount of abuse it's able to take I haven't been this impressed since I stepped out of the shower dripping wet (sorry for that visual). Thank you for the video!
I saw this idea in rocks sphere manufacturing. If you have good drill press you can try using sphere cutters from china.
Biggest I buy was for 50mm dia spheres.
Or use this method of preparing sphere blanks for sanding th-cam.com/video/JB0x5v5WUYE/w-d-xo.html
No balls, no glory!
🙂❤❤❤❤
Interesting machine, however overly complex...
You do realize that any object left to bounce on a flat surface will inevitably tend towards a sphere ?
All you need is a moving abrasive flat surface, like a disc from an angle grinder, and a way to loosely constrain the wooden piece. Then you can even start with a cube and it will grind itself into a sphere...
Sounds interesting. Do you have a link to such a machine?
@@FraensEngineering I'll check and post but here is maybe a more practical description of such an implementation:
Take a tube 50cm long, 15cm diameter. Mount vertically. The top open end is where you drop the block of wood (say 5cm long) to be rounded.
On the bottom end, place an angle grinder with a sanding disc, so that the disc essentially covers the opening.
drop a block of wood in the tube while the grinder is running.
The important part is that the wood piece should bounce around and roll randomly, if it gets caught, it will just grind a flat. So chopping off each corner of the cube to grind will help.
It's great that it works like this. That would be an excellent method for preforming the balls. With the Sphere machine you can then finish grinding and polishing them.
@@FraensEngineering yes, but you can also polish as long as the disc has very fine abrasive, or a felt pad with polishing paste ( and the cylinder interior could also be felt lined and polishing paste loaded )
@@bschwand yep. or mount an orbital grinder above a flat board with sanding sheet, and a spacer in between with a hole cut through to shove the item in. the orbital motion helps...
some sort of feeder so you can adjust the gap between sanding surfaces...
pretty well much how ball bearings are made, though they do start with a forged, "close to ball shaped" lump of steel.
this approach, using the three cutters, is more trended towards the final polishing process, not rapid material removal.
Anybody wants to make their own, 4 would have been better than 3. Because the real world is 3D and not 2D. It's obvious when he had to hold it in because it was falling out.
I don't think this is the way you describe it. Professional ball machines work exactly according to this principle. I only had to hold the ball in place because the ball was very inaccurately pre-cut.
Very interesting ideas ! But it's either unwillingly wrong or plainly clickbait: it should read something along the lines of "3D printed sphere *polishing* machine" the way it's worded gives us the impressing that the machine actually makes the spheres.
Hello, such machines are called Sphere machines. Unfortunately there is nothing I can do about it. If you took it as clickbait, I apologize.
You mean sphere-sanding machine...
Wow!!!!😮
👏👏👏😎👏👏👏
👍
You certainly found a way to get some balls. You just took the saying too literal.
Токарный станок похоже стерт из этоц реальности
Bocce anyone?
no chance this actually works.
Am I the only one triggered by his improper use of wooden T-nuts?
Of course, you can also drive just one grinding head. But what exactly is the point?
@@FraensEngineering T nuts are designed to be used under compression, not under tension. You've installed them all under tension by putting them on the the same side of the board as their bolts. The result is that, under low to modest load, the nuts will come loose (pop out of the board). They cannot typically support more than a few pounds of force in this configuration.
If you had instead placed the nuts on the bottom of the board (opposite to the bolts, as they're designed to be used), then the nuts would be capable of supporting orders of magnitude more load, and it did likely contribute to a stiffer mechanism overall. Each nut would then be able to support over a hundred pounds of force.
Do you mean the melt-in nuts?
@@FraensEngineering no, I mean the T nuts you pounded into the wood. i.e. the "wooden T-nuts" that I said in my first comment.
Search for "t-nuts for wood" on Google and you'll know exactly what I'm talking about.
potato :D
Alô @manualdomundo