New build (I hope so) in France

[Zm@steR]

Hi there,

I started lurking around after discovering Lenne's CN on BitTech about a year ago.
Since then I became a bit obsessed with building a CN.
At first, I dreamed myself building a huge one then the cost for such a machine bring me back to reality
so I planned to build a tiny one with drawer rail or so .
Eventually I decided to put some money in it to get something that would allow me to mill plastic, wood
and (I wish) 5mm alu plate even if I got to do it in severall time.

I began by buing this kit on ebay.

SBR16-300/800/1300mm(6supported rails and 12 SBR16UU bearing blocks)
3pcs RM1605-350/850/1350mm with ballnuts and end machined
3sets BK/BF12 end support with locknuts and circlips
3pcs couplers 6.35mm*10mm

I am waiting for them to get started with the plans.
I will get the electronic once the frame is going to be usable.
Due to lack of money I intended to use MDF to build it, but I might have an opportunity to get some 40*40 & 40*80 alu
profiles , I'll keep you posted about that.

In the end I would like to get somthing like Lenne's V1

Sorry about if there are some mistakes, I'm still trying to improve my english.
Feel free to post any comments or suggestions.
Z

[lenne0815]

I dont mind, but asking is always a good way to start if ure using other peoples pics.

[Zm@steR]

asking is always a good way to start if ure using other peoples pics

Trully sorry about that, I just wanted to "picture" what I intend to do since my sketches are not ready yet.
I didn't occured to me at the moment to ask you before using your pic.
Sorry again.

[OCNC]

Trully sorry about that, I just wanted to "picture" what I intend to do since my sketches are not ready yet.
I didn't occured to me at the moment to ask you before using your pic.
Sorry again.

I wouldn't feel too bad. After all you're just linking and you did give credit. In the end it's the free exchange of information that makes this site work. Check out Mike Everman's posts and the generous way he's exposed all of the details of his proprietary development of the servo-belt drive.

[Zm@steR]

QUICK UPDATE

One of my coworker had a present for me

There are some 40*40, 40*80 & 50*50 alu profiles.
I am still waiting for the rails & bearings.

BTW does any of you have some tip about how I could fixe the rails ?
As I intend to use the 40*80 profile and the support of the rail is 40 at the base, it going to be tricky to tide them.
Z

[lenne0815]

I wouldn't feel too bad. After all you're just linking and you did give credit. In the end it's the free exchange of information that makes this site work. Check out Mike Everman's posts and the generous way he's exposed all of the details of his proprietary development of the servo-belt drive.

Im not offended by it anyway, that was meant more as a tip in general, its always nice being asked if someone wants to use ur work for whatever purposes, sometimes i find it linked in the weirdest places

back on topic, i do not really understand what ur mounting Problem is, maybe u can make a pic to show it ?

[Zm@steR]

Ok not the best sketch but it will do the trick.

From left to right
- what Lenne did on his V1 (it seems to work fine for him but IMO it may be improved a bit)
- what would be perfect (but it would require to get a 30*60 alu profile)
- what I am currently thinking about (no idea if it's possible and suitable)

Hope it's clear enought.
Every suggestion/advice is welcome
Z

[PaulRowntree]

The middle picture shows how it is supposed to work, if the hole spacing works. The right may work, but it goes against the working ideas of using 8020 stock.
1) you are drilling through holes, and therefore not taking advantage of the extrusions flexibility with slots.
2) The std way of tightening with 8020 pulls the extrusion up against the bottom of what is being attached, increasing the contact area as you tighten; the extrusion is initially bent down towards the slots to make this effective. Your bolts are trying to compress the wall on the other side of the extrusion in toward the middle (ie in the opposite direction) without deforming towards the contact surface. You are concentrating the forces to a few contact points instead of distributing them to create contact surfaces.

[DonFrambach]

I'm no expert so take with a grain of salt. I think your option number 3 is suboptimal because tightening the bolt would tend to crush and deform your extrusion. When I mounted as SB20 rail on an 8020 extrusion, I made a steel adapter plate. The plate is bolted to the extrusion, the SB20 rail bolted to the steel adapter. Another builder simply tapped the 8020 extrusion and this seems to be working fine. Here's a link to his build: http://www.cnczone.com/forums/cnc_wo...tml#post985034

[lenne0815]

I'm no expert so take with a grain of salt. I think your option number 3 is suboptimal because tightening the bolt would tend to crush and deform your extrusion. When I mounted as SB20 rail on an 8020 extrusion, I made a steel adapter plate. The plate is bolted to the extrusion, the SB20 rail bolted to the steel adapter. Another builder simply tapped the 8020 extrusion and this seems to be working fine. Here's a link to his build: http://www.cnczone.com/forums/cnc_wo...tml#post985034

A big washer would solve that problem though, i would go for solution 3; u can unscrew the rail from the support and then drill and tap it.

[Zm@steR]

The middle picture shows how it is supposed to work, if the hole spacing works.

That's the problem, the hole spacing doesn't match.

2) The std way of tightening with 8020 pulls the extrusion up against the bottom of what is being attached, increasing the contact area as you tighten; the extrusion is initially bent down towards the slots to make this effective. Your bolts are trying to compress the wall on the other side of the extrusion in toward the middle (ie in the opposite direction) without deforming towards the contact surface. You are concentrating the forces to a few contact points instead of distributing them to create contact surfaces.

Indeed, one other solution is to put a plane steel in the slot underneath the rail support, but I still have to drill threw the 8020 to screw the bolt from the bottom.

I'm no expert so take with a grain of salt. I think your option number 3 is suboptimal because tightening the bolt would tend to crush and deform your extrusion. When I mounted as SB20 rail on an 8020 extrusion, I made a steel adapter plate. The plate is bolted to the extrusion, the SB20 rail bolted to the steel adapter. Another builder simply tapped the 8020 extrusion and this seems to be working fine. Here's a link to his build: Redirecting...

Thx for the tips I'll think about those.

A big washer would solve that problem though, i would go for solution 3; u can unscrew the rail from the support and then drill and tap it.

What do you mean by "drill an tap it" I just want to unscrew the original bolt and replace them with longer ones, so I will just have to drill the 8020 and the plane steel
I will slide in the upper slot or underneath the 8020 and then rescrew everything.

[lenne0815]

What do you mean by "drill an tap it" I just want to unscrew the original bolt and replace them with longer ones, so I will just have to drill the 8020 and the plane steel
I will sled in the upper slot or underneath the 8020 and then rescrew everything.

Slide ? i wasnt aware that ur supported rails already have threads for fixing them in the middle, mine didnt ( that makes it even easier ) and make sure u drill the holes through the 8020 a fair bit bigger than ur screws gonna be, otherwise u wont have a chance to align them properly later on ( this applies only if ur screw goes through the whole profile )

If ure going to drill the profiles anyway u could still mount them as shown in pic 2 it would just require some more holes.