[rockom]

Hello all,

If this has already been done, let me know. Send the link to the post if you have it. So far, I have not seen this method.

Here is a concept that I intend to use on my machine. The complete machine is based on the JGRO plans with some modifications. The first modification I intend to implement is described here. Please check out the pictures.

The angle iron will be supported by the machine frame allowing the pipe to be freely suspended (just like JGRO's pipes). Pic 1 shows how I cut slots for the end mounting bolts. This allows me to adjust the pipes further away or closer to the angle iron by turning the appropriate nuts. Pic 2 shows the rails with a bearing assembly zip tied in place. Pic 3 is a close-up of the support adjustment bolts. Pic 4 is a close-up of how I bolted the ends of the pipe to the angle iron. Pic 5 and 6 are of the whole rail assembly. In order to flex the pipe, you would need to flex the entire assembly. The rail shown is only 3ft long (x-axis) but I plan on having 5ft rails on my y-axis. That's the main reason I'm trying to support the pipe.

My adjustment bolts are obviously way too long. They are what I have available until my next trip to the store. So what do you think? Please reply with your comments, suggestions, criticism, or whatever you have to offer. I'm looking for possible weaknesses and methods of improvement. After I get some feedback, I'll move forward building the rest.

What I like best so far, is I was able to make the whole thing using my drill press and a few clamps. The worst part was getting two perpendicular holes on one end of the pipe to be perfectly in line with two perpendicular holes on the other and of the pipe. My fabrication methods definitly need improveing. I came very close to perfect but, one of my holes is a little bit off. I had to wrestle with it a little while assembling. One other dawback is it adds considerable weight to the gantry.

-Rocko

[Verfur]

I woder if you can find some washers with the radii of the pipe on one side and flat on the other side? I think it would help keep from destortion and maybe more rigid.
I gues the 2 bearings would roll on the top sideeach isde of center of the pipe and the one bearing would be on bottom outside. The bearing on the bottom will it be far enough under to keep it from rocking? Oh on the holes being in the same plane as each other may want to look for a used "pipe head" it uses a punch, a V and an level,
A weld shop will now what you are talking about maybe even a pawn shop. work very well for low tech.
please post any progress (I like it so far)

John

[rockom]

Verfur,

We think alike. I was trying to think of a way to make some sort of washer or support with the radii of the pipe. So far I came up with drilling holes in bar stock. The holes will be the diameter of the pipe. Then cut them in half with the band saw. That gives you the radii. I think it sounds expensive. Maybe some hardwood or UHMW plastic would be suffiient. Maybe the dont even need to have a radii. Something with a 1/4" V groove might be ok.

Playing with the design, The bearing assembly bolts come very close the rod support bolts. This reduces room for adjustment. Definitly need to put some more thougth into this.

I'll look for a "pipe head" device. Thanks for the info.

EDIT: Reading back through my reply, I see an issue. Supports that have the radii of the pipe would need to be very narrow for the bearing assembly to clear them. I think they would still be worth adding.

-Rocko

[Verfur]

? smaller bolts maybe? Sence ther are so many say somthing like 1/4-28, I now that I have to watch myself or I will make stuf so beefy you cant even move it. My family have bin in R/C aircraft for 30 plus years and the thing we have finaly got, is that geometry is better than extra beefy.

How much weight do you think you will need to suport?

How strait is the pipe? we have ben kicking around the V-bearing and angle iron, but the pipe with roller bearings is a consederation for the next (bigger) machine.

It would not supprise me to find the trick washers at a Industrail bolt co. the thing is you may have to buy a hundred or two still be time and money ahead though vrs. making them.

John

[Verfur]

I got a better look at your roller asm. are you just useing the weight of the gantry to hold it down? How well does that work on a router?

John

[rockom]

All bolts in the pictures are 1/4-20.
I'm not using the weight of the gantry to hold them down. They will ride the rails exactly like JGRO's. The pipes will be in the same pisiotion as in JGRO's....I'm just adding the angle iron. The bearing assemblies will be "captured" between the pipes and gantry.

[Verfur]

aaaha,

cool that makes more sence to me. the pics are deciving to me at first Now that I have looked again (a little closer) I see the bolts are smaller than I thought. I was thinking of one for myself in the 4ft by 8ft range with like maybe somthing in the order of 1.5 to 2 inch pipes. How big will yours be when finished?

P.S. I have not studied the JGRO much as I probaly should

thanks for the information

John

[rockom]

Verfur,

My X axis pipe is 3ft long (pictures above). I'll lose about 3 inches off each end for mounting. I hope to get 2ft of cutting surface out of whats left. For the Y axis I'll be using 5ft pipes. I should have no problems getting close to 4 ft of cutting surface out of that.

I'm using 3/4" pipe on the X and 1" on the Y.

-Rocko

[rockom]

Anybody else?

[spalm]

Looks like an inexpensive, non-flexing rail. But I’m not sure I see how you are going to mount it.

“The angle iron will be supported by the machine frame allowing the pipe to be freely suspended (just like JGRO's pipes).” ???? Are you going to use the 4 bolt adjuster thingies at the two ends?

Steve

[rockom]

Well since I don't have it built up yet, I'll try and explain. I wont need the four bolt adjustment because I can accomplish the same results be adjusting the bolts on each end of the pipe that go all the way through. In my MDF frame pieces I'll cut square holes instead of round holes (in the same location as JGRO's four bolt adjustment block) . The angle iron will go through the square holes far enough to bolt them down. I don't have those holes drilled yet on the iron. I'll bolt the angle iron to an L shapped piece of MDF or UHMW. Then bolt the L piece to the end piece face. The angle iron will sort of double as more support for the frame along the axis. Kind of hard to explain or understand without seeing it. The important thing is, the angle iron is fixed to the frame. The pipe will not touch anything it isn't already touching in the photos above. I was trying to model this in Solidworks but, I'm not so good at that yet.

Make sense? Unfortunatly I'll be gone most of the weekend and am not sure how much progress I'll be able to make. One rail assembly took me a long time to make. I'll post updates but they will be slow.

Any othe questions, just let me know. Keeps me thinking about how to improve the design.

-Rocko

[jimini]

That's basicly what I did on my machine before I went to THK rails.

http://www.cnczone.com/gallery/showp.../54/ppuser/410

Width adjustment was threaded rod between rails. Your width adjustment is better I think.

[rockom]

Jimini,
I saw the picture of your machine a while back. That picture is actually what inspired my design. What is the metal "cylindrical" object you have between the pipe and nut? Looks like some sort of spacer. Does it fit the radius of the pipe?

I have the pipe supports ever 6" from center.

Thanks,
-Rocko

[jimini]

The cylindrical object is drilled to fit over the bolt, and is tapped for a horizontal threaded rod that is width adjustable, to space the rails.
The rails I used were a thick walled smooth pipe with about 1/4" walls.
I then ran a 3/8" threaded rod throught them lengthwise, with nuts on the ends.

[rockom]

jimini,

Sounds good. Where did you get that kind of pipe? Whats it's more common use?

-Rocko