Another New JGRO Build - Advice Sought...

[dbprojects]

OK – now it’s my turn for a new JGRO build.

I’ve been lurking/reading for months on this site, and have ordered (and received) the 305 oz/in 3-axis package kit from HobbyCnc. Soldering __should__ commence this weekend…

I’m at the point where I have to commit to some of the details, so I’d like some advise:

CONSTRUCTION:
I have some ¾ in birch plywood left over from a recent job, and am wondering if this would be superior to ¾ in MDF? While the dimensional stability of any hardwood probably would not be as good as the MDF,
I would think that the plywood would be Nearly the same as MDF.
There would certainly be less “tear-outs” from tapped holes etc. Opinions???

GLUE: I’ve read that some builders do/don’t use glue on their builds – I’m thinking of
Gluing the base, and possibly some of the Z-axis frame. Any recommendations for or against?
Also, I’ve read somewhere (???) about a certain type of tap that should be used when tapping MDF. I can’t find the link again. As I remember, it does a better job with composites like MDF – any suggestions?

LEADSCREWS: From reading other posts from JGRO builders, I’m certainly not going to use the ¼ - 20 threaded rod - But the question is: If I use ½ - 10 Acme 1-start ($6.99 for a 6 foot length from ENCO), can I later substitute it for ½ -8 Acme 2-start from McMaster Carr or MSCdirect? (about $45 - $60 for a 6 foot length!!). I would imaging that the bearings and LoveJoy couplers could be re-used.
[So – why is there such a huge difference between ENCO and MSC (even for the same ½-10 1 start rod - about $25 from MSC vs. $7 from ENCO. Is the ENCO rod of similar quality ??? Will the ENCO ½-10 Acme 1-start rod get me started for a while???]
I figure that from the RPM vs Torque graphs, I can/should run the motors at a max of 400 RPM before the torque significantly rolls off (or they start to whip) – this should get me about 40 inches per minute using the Excel spreadsheet from the FAQ section???

COUPLERS:I’d like some advise about the LoveJoy couplers vs the DumpsterCNC ACME couplers.
As I see it, the Lovejoys are half the price, and can be re-used if I upgrade to ½-8 Acme 2-start rods. I’d have to purchase a different set of couplers if I went for the DumpsterCNC type. I’m also assuming that the LoveJoy couplers only need you to possibly make a flat spot on the Acme rod – no keyway needed to machine, and the rod does not have to be turned down. I also think that the loveJoys would be more forgiving to mis-alignment of the rod to the motor – I would think that a direct coupling could result in forces on the motor bearings that they were not designed for.
For the reasons just mentioned, I’m leaning towards the LoveJoys – but are they good enough? Do they exhibit much “slop”?

SIZE: I’ve read that the usable table size of the JGRO is about:
> Jgro: The cutting area is about 30" x 15" x 6".

And that some of the pieces of the Joe2006 are too large to make on this table.

>Some of Joe's part measurements that are longer than the JRGO can cut:
>Router end supports 33.95"~
>Torsion box bottom 34.5"~
>Gantry sides 30"~
>Torsion box long braces 41.36"~

From reading this site, it seems *everyone* makes a second, third… machine!
So… If I expand the JGRO to have a usable table size of about 42” x 20” x 6” , and use the rail stabilizing technique that I’ve seen on this board (reddish/orange pipe supports – possibly from GliderGider’s build), would I be satisfied with the result, or would I only get aggravation ? [Note that I’m planning on adding that mod to the basic JGRO once it is up and running anyway]. Like they say, “size isn’t everything”… should I stick with the basic JGRO footprint to start out with?


4TH AXIS:
My long term plans are to build up a 4th axis, But I’d probably start with a manual indexing jig – so that I can accurately flip a piece of work over to rout the bottom.
From all of my reading etc., I haven’t seen a JGRO or Joe2006 with any type of 4th Axis – anyone using one? (or have a link to a “real cheap” method of doing this?)

INSTRUCTIONS:Is there a set of written text instructions (similar to what Joe did for the Joe2006), for the JGRO? If not, they are obviously not needed, based on the number of JGRO’s I see out there - but a text writeup with some hard learned assembly/alignment tips would be nice… [note that I’ve gone through most, if not all of the JGRO build threads, and have squirreled away all the tips that I’ve seen]

SOFTWARE:
Well – that’s a whole other set of questions…


Thanks,
Don

[silentreaper]

Originally Posted by dbprojects OK – now it’s my turn for a new JGRO build. I’ve been lurking/reading for months on this site, and have ordered (and received) the 305 oz/in 3-axis package kit from HobbyCnc. Soldering __should__ commence this weekend… I’m at the point where I have to commit to some of the details, so I’d like some advise: CONSTRUCTION: I have some ¾ in birch plywood left over from a recent job, and am wondering if this would be superior to ¾ in MDF? While the dimensional stability of any hardwood probably would not be as good as the MDF, I would think that the plywood would be Nearly the same as MDF. There would certainly be less “tear-outs” from tapped holes etc. Opinions???

Honestly I couldn't help you on this as my whole build is MDF except for bearing and adjustment blocks.

Originally Posted by dbprojects GLUE: I’ve read that some builders do/don’t use glue on their builds – I’m thinking of Gluing the base, and possibly some of the Z-axis frame. Any recommendations for or against? Also, I’ve read somewhere (???) about a certain type of tap that should be used when tapping MDF. I can’t find the link again. As I remember, it does a better job with composites like MDF – any suggestions?

As far as gluing I glued both of the torsion boxes just not the top skin that one is screwed on, one thing to think about is, if MDF acts the same way with glue as what I call particle board (basically the same as MDF but slightly larger fiber particles), when ever we would glue particle board together and brad nail or staple it, if you needed to disassemble, you might as well just build a completely new "insert name of part here" because you will simply destroy what ever it is your need to take apart.

The tap is a roll form. Thats what we call them, the tap acutally "forms" the material into threads as apposed to cutting which is what you can get when you buy a tap at any hardware store. Another thing to know about roll form taps is you need to drop you drill size a bit. When I used to work at "terrible machine shop/assembly facility.IND" we cut aluminum almost exclusively, and we used roll form taps almost exclusively, it was rare to use a cutting tap at all, then again we weren't a prototype/short run facility either we ran high volume orders.

Originally Posted by dbprojects LEADSCREWS: From reading other posts from JGRO builders, I’m certainly not going to use the ¼ - 20 threaded rod - But the question is: If I use ½ - 10 Acme 1-start ($6.99 for a 6 foot length from ENCO), can I later substitute it for ½ -8 Acme 2-start from McMaster Carr or MSCdirect? (about $45 - $60 for a 6 foot length!!). I would imaging that the bearings and LoveJoy couplers could be re-used.

Yes you can but of course, you would need a few thing changed eg. AntiBacklash assembly, nuts and the like, basically anything that is using the 1/2-10 thread would also have to be changed to use the 1/2-8 2 start.

Originally Posted by dbprojects [So – why is there such a huge difference between ENCO and MSC (even for the same ½-10 1 start rod - about $25 from MSC vs. $7 from ENCO. Is the ENCO rod of similar quality ??? Will the ENCO ½-10 Acme 1-start rod get me started for a while???] I figure that from the RPM vs Torque graphs, I can/should run the motors at a max of 400 RPM before the torque significantly rolls off (or they start to whip) – this should get me about 40 inches per minute using the Excel spreadsheet from the FAQ section???

Couldn't tell ya why such a price difference as I went right to 1/2-8 2 start (after finding out how bad an idea it was to use the 1/4-20) from MSC.

Originally Posted by dbprojects COUPLERS:I’d like some advise about the LoveJoy couplers vs the DumpsterCNC ACME couplers. As I see it, the Lovejoys are half the price, and can be re-used if I upgrade to ½-8 Acme 2-start rods. I’d have to purchase a different set of couplers if I went for the DumpsterCNC type. I’m also assuming that the LoveJoy couplers only need you to possibly make a flat spot on the Acme rod – no keyway needed to machine, and the rod does not have to be turned down. I also think that the loveJoys would be more forgiving to mis-alignment of the rod to the motor – I would think that a direct coupling could result in forces on the motor bearings that they were not designed for. For the reasons just mentioned, I’m leaning towards the LoveJoys – but are they good enough? Do they exhibit much “slop”?

From what I read (actually it was joe2000 that said thats why he made his own jovejoy spiders, cause they had a bit of slop. And yes the lovejoys are much more forgiving of slight misalignments than the acme couplers at dumpster, I bought 1 acme coupler from dumpster just for the Z axis as I find the Z axis to be the easiest to get a perfect alignment on.

Originally Posted by dbprojects SIZE: I’ve read that the usable table size of the JGRO is about: > Jgro: The cutting area is about 30" x 15" x 6". And that some of the pieces of the Joe2006 are too large to make on this table. >Some of Joe's part measurements that are longer than the JRGO can cut: >Router end supports 33.95"~ >Torsion box bottom 34.5"~ >Gantry sides 30"~ >Torsion box long braces 41.36"~ From reading this site, it seems *everyone* makes a second, third… machine! So… If I expand the JGRO to have a usable table size of about 42” x 20” x 6” , and use the rail stabilizing technique that I’ve seen on this board (reddish/orange pipe supports – possibly from GliderGider’s build), would I be satisfied with the result, or would I only get aggravation ? [Note that I’m planning on adding that mod to the basic JGRO once it is up and running anyway]. Like they say, “size isn’t everything”… should I stick with the basic JGRO footprint to start out with?

Can't help you here.

Originally Posted by dbprojects 4TH AXIS: My long term plans are to build up a 4th axis, But I’d probably start with a manual indexing jig – so that I can accurately flip a piece of work over to rout the bottom. From all of my reading etc., I haven’t seen a JGRO or Joe2006 with any type of 4th Axis – anyone using one? (or have a link to a “real cheap” method of doing this?)

Again no help here.

Originally Posted by dbprojects INSTRUCTIONS:Is there a set of written text instructions (similar to what Joe did for the Joe2006), for the JGRO? If not, they are obviously not needed, based on the number of JGRO’s I see out there - but a text writeup with some hard learned assembly/alignment tips would be nice… [note that I’ve gone through most, if not all of the JGRO build threads, and have squirreled away all the tips that I’ve seen]

Tip: Don't over tighten anything, especially if you use MDF.

Originally Posted by dbprojects SOFTWARE: Well – that’s a whole other set of questions… Thanks, Don

[tajord]

SIZE: I’ve read that the usable table size of the JGRO is about: > Jgro: The cutting area is about 30" x 15" x 6". And that some of the pieces of the Joe2006 are too large to make on this table. >Some of Joe's part measurements that are longer than the JRGO can cut: >Router end supports 33.95"~ >Torsion box bottom 34.5"~ >Gantry sides 30"~ >Torsion box long braces 41.36"~ From reading this site, it seems *everyone* makes a second, third… machine! So… If I expand the JGRO to have a usable table size of about 42” x 20” x 6” , and use the rail stabilizing technique that I’ve seen on this board (reddish/orange pipe supports – possibly from GliderGider’s build), would I be satisfied with the result, or would I only get aggravation ? [Note that I’m planning on adding that mod to the basic JGRO once it is up and running anyway]. Like they say, “size isn’t everything”… should I stick with the basic JGRO footprint to start out with?

I've made mine longer, X is about 46" cutting area, it's not a problem:
http://www.cnczone.com/forums/attach...7&d=1177635932

4TH AXIS: My long term plans are to build up a 4th axis, But I’d probably start with a manual indexing jig – so that I can accurately flip a piece of work over to rout the bottom. From all of my reading etc., I haven’t seen a JGRO or Joe2006 with any type of 4th Axis – anyone using one? (or have a link to a “real cheap” method of doing this?)

I've seen something i don't know if it'll help you, don't know how far he got with it, take a look:

http://www.cnczone.com/forums/attachment.php?attachmentid=33325&d=1173572303

here's his thread:

http://www.cnczone.com/forums/showth...light=lionclaw


good luck.

edit: Sorry about the "bold" can't seem to get it all taken out

[Glidergider]

Looks like great advice from Jordan and the SilentReaper. So I won't add anymore duplicate advice.

Here's my limited comment. Don't tap all the threads that plans call out. Drill and pilot for a wood screws. Use all the suggested bolt locations, but use long phillips head (trumpet head) wood screws. It's so much faster and just as strong. Glue most all the joints with carpenters glue. Some joints I didn't glue, so I'd have access later. Table top is one of those joints.

Your reference to my stabilization method is a misquote. My table is standard length and I didn't stablize the X axis. I forgot who did that, but I know what you're talking about.

Good luck with your build. If your skills with computer CAD is pretty good, then I'd recommend that you build the Joe's2006R2 rather then the JGRO. If you are like me (I wanted a paper drawing) then go with the JGRO.

[dbprojects]

SilentReaper,

Thanks for the inputs. I'll look around to see where I can get the correct "roll form" tap.

So, if you only bought 1 acme coupler from DumpsterCnc, did you use LoveJoys for the other 2 axis?

Thanks again,
Don

[dbprojects]

Tajord,

Very, very nice build!
You said that your cutting area (x) is 46". Did you keep the other axis as they were (y=15, z=6)? I realy like the enclosed base - it must cut down on the sawdust getting everywhere.

Also, thanks for the 4th axis link. It's something to think about for the future...

Don

[dbprojects]

Originally Posted by Glidergider Looks like great advice from Jordan and the SilentReaper. So I won't add anymore duplicate advice. Here's my limited comment. Don't tap all the threads that plans call out. Drill and pilot for a wood screws. Use all the suggested bolt locations, but use long phillips head (trumpet head) wood screws. It's so much faster and just as strong. Glue most all the joints with carpenters glue. Some joints I didn't glue, so I'd have access later. Table top is one of those joints.

Dave, by "trumpet head", do you mean drywall screws? Also, what other parts would you not glue?

Originally Posted by Glidergider Your reference to my stabilization method is a misquote. My table is standard length and I didn't stablize the X axis. I forgot who did that, but I know what you're talking about.

I'll have to go back through the build logs to see who did that. With the experience that you have using your JGRO, would it be something to think about adding?

Originally Posted by Glidergider Good luck with your build. If your skills with computer CAD is pretty good, then I'd recommend that you build the Joe's2006R2 rather then the JGRO. If you are like me (I wanted a paper drawing) then go with the JGRO.

I started out on the Joe2006 path, but it realy looks like you need a CNC setup to do it justice. I know that other(s) have made it with hand tools, but I think I'd do better with the JGRO as a first machine - and then possibly use it to make a larger/sturdier unit. With the possibility of a second machine, I'm leaning towards using the cheap 1/2-10 ACME 1 start leadscrew from ENCO, instead of the more expensive 1/2-8 2 start... I can always upgrade the JGRO later, or use the 2 start in the second unit...

By the way - what do you guys do with your 1st / 2cnd / 3rd machines???

Thanks,
Don

[Glidergider]

I had no idea how much enjoyment I'd have with this hobby. At this point, if I could have done it again, I'd build a Joe2006. Mostly for the extra inches. I'm not even sure how much bigger they are, but I want a bigger table now. I'm also a lot braver now after working in this hobby for 6 months. Plus, I would give me an excuse to buy a band saw to help cut out those complicated parts.

Never mind that I said all this. I'm having a GREAT time with my JGRO.

The other thing to avoid glueing are the aluminum angles that hold the bearings. You may need to shim that and if you, well, it will limit your adjustment.

[tajord]

Tajord, Very, very nice build! You said that your cutting area (x) is 46". Did you keep the other axis as they were (y=15, z=6)? I realy like the enclosed base - it must cut down on the sawdust getting everywhere. Also, thanks for the 4th axis link. It's something to think about for the future... Don

hey no prob, we are here to help, the other axiis remained the same, you'll be able to extend the y axis you just have to bare in mind that the longer those pipes get, the more it'll be able to flex, i'd recommend trying to support the pipes somehow, the enclosed base does capture quite a bit of the dust, but sorry to say it will not stop it, it gets everywhere, i still at this point have not yet made my dust collector, (shame shame) trust me you'll need one.

good luck.

[silentreaper]

Originally Posted by dbprojects SilentReaper, Thanks for the inputs. I'll look around to see where I can get the correct "roll form" tap. So, if you only bought 1 acme coupler from DumpsterCnc, did you use LoveJoys for the other 2 axis? Thanks again, Don

Ah man sorry bout that, I thought I mentioned that, yes I got 1 coupler from dumpster and am using lovejoys on the other 2 axis.

Reaper

Edit: and as far as the roll form taps, a quick look at MSC the cheapest 1/4-20 they have is $9.61 but they do have them, apparently they are really called "thread forming" taps, well I guess thats what you get when you work at a place that uses there own lingo long enough.

[dbprojects]

Originally Posted by silentreaper Ah man sorry bout that, I thought I mentioned that, yes I got 1 coupler from dumpster and am using lovejoys on the other 2 axis.

So Reaper,
What are your experiences with the LoveJoys? Is there very much slop?

Don

[silentreaper]

Originally Posted by dbprojects So Reaper, What are your experiences with the LoveJoys? Is there very much slop? Don

Well let me tell you, I think it is the luck of the draw, as with most manufactured parts, you have an amount of tolerance with your dimensions, I bought 2 sets, 1 set of .25" and 1 set of .5" and a set of the rubber spiders, now when I matched up 1 pair they fit beautiful, the other pair I matched up has a small, very small amount of slop (like the .5" hub was made on the low end of the tolerance and the spider was made on the high end), but it is enough to notice a difference between the 2 sets, so you might get a set that fits beautiful you might get a set that is just sloppy as...well I think you might get the picture here.


Reaper