[RedLabel]

Well, just as I thought everything was going fine I realized that the guy who was cutting the wood parts for me actually did Nothing. Still angry but I'll go on.

I'll have the parts cut to a reliable person very soon. I modified and redraw the jgro as seen on the pictures. Found some bearings for the threaded mill. Also I will get some couplers made for connecting the mill and the steppers.

Fixing the pipes seemed a little problematic for me. In the apparatus seen below are the nuts glued to the surface. Is there another way to fix the pipes?

Thanks
(attaching the pictures of my modified jgro too)

[edo]

The "Adjustment Block" assemblies allow you to adjust the pipes. It's doubtful that you'd be able to measure and drill the endplates accurately enough that the pipes will be level and parallel. If only it was that easy.

The holes on the four sides of the adjustment blocks are threaded for the bolts and the nuts are placed on the bolts before screwing them into the block. You turn the bolts in and out as needed to hold the pipe in the adjusted position, then turn the nut tight against the block to lock the bolt in position.

Hope this helps.

[RedLabel]

thanks for the reply but I'm still confused.

Isn't the adjustment block made of mdf too? Threading inside of mdf doesn't seem like a good idea. And how does the nut lock the bolt in position if it is not fixed anywhere else?

Thanks

[edo]

If you read through the plans you'll see that there are a lot of threaded holes in the MDF on just about every piece. They hold. Some people recommend putting cyanoacrylate (Super Glue) on the threads to make them stiffer and less prone to pull out. Depending on how much glue the MDF soaks up, you may have to run the tap through the hole one more time.

When you turn the bolts into the adjustment block they tighten against the gas pipe to hold it where it needs to be. With the bolts tight against the pipe, when you turn the nuts against the block they will tighten and will keep the bolt from loosening. Over tightening the nuts can pull the bolt out of the MDF threads.

Here's a picture of my Gantry. Notice how the pipes are sitting in the adjustment blocks. The top pipe is almost at the bottom of the block and the bottom pipe is almost at the top. Even though I was careful in cutting every piece I still had to adjust the pipes almost to their limits to get the Z axis to ride tightly between them.

[RedLabel]

Now it is clear(I always thought threaded mdf wouldn't hold).

Thanks a lot...

[tajord]

just want to add a note, from what i've seen and experienced, a good hardwood like "oak" seems to hold threads a lot better than MDF for the adjustment blocks, I've tried this with "purple heart" and it turned out quite well.

[RedLabel]

Btw, is there an easy way to open threaded holes?

[edo]

I don't understand the question - what do you mean by 'open'?

[RedLabel]

I mean drilling the threaded holes.

[edo]

You just use a drill and tap. There are two different size holes in the JGRO build:
10-24 - use a #25 drill bit and 10-24NC tap
1/4"-20 - use a 13/64" drill bit and a 1/4"-20NC tap

If you don't have the drills or a tap and die set, you can buy the individual size taps you need and they'll come with the appropriate sized drill bits in a pack for only a couple of bucks each.

[RedLabel]

finally completed cutting the parts. It is nice to see them together doesn't it .

For most of the build I'll use Bison montage kit construction adhesive. It is really strong, hope will eliminate the need for most of the bolts.


I'll start the assembly tomorrow, will post pictures as I proceed.

[edo]

Looking good. The hard part's done - you'll be cutting in no time. Keep us posted.

[tajord]

hey red label, how's the build going these days?

[Glidergider]

Red,
Did you finish drilling and tapping those holes? Probably.

If I were building another one, I'd skip most of the drill and tap notes and just use wood screws. It will go together just as strong, maybe stronger. Drill clearance holes in the outside part and pilot holes for the mating part. It goes together quicker.

But I did enjoy, on some level, making all those tapped holes.

On the adjustment blocks, don't tap the mounting holes. Use wood screws there.

These are just my methods.
Dave

I mean drilling the threaded holes.

[RedLabel]

it has been several months now and I gave up jgro after building the z-axis. I decided to go for the cheap linear bearings which simplified everything greatly.

btw I tapped a lot of holes, they were working as you've said but takes a lot of time and not worth the effort since I used Bison's PU based glue which was fast and very strong.

And here is the link to my machine, any advice will be great.

http://www.cnczone.com/forums/showthread.php?t=40151