New UK JGRO

[NB70]

I have nearly finished a JGRO build in the UK. At the start of the project my experience in CNC (and woodwork!) was just about zero, but the great plans and the mountain of useful information at cnczone.com made it possible to complete the machine. My stated reason for building the machine was to make parts for guitars, but I really just wanted to make a robot and I had great fun doing it.

My version of the JGRO is similar to the plans with some minor differences:

• My build used all skate bearings.
• The lead screws are M8 threaded rod, supported each end by skate bearings and double nuts.
• The steppers stand proud of the MDF frame on plastic mounts (I think I got the idea from GliderGlider's thread) and are coupled to the lead screws with lovejoy type couplers.The lead screws are under tension which stops them whipping about at speeds (I haven't used the anti-whip block).
• I couldn't find any gas-pipe over here in the UK so I used cold-rolled steel tube for the Z and Y axes and some hand-rail for the X-axis. I am prepared to replace these tubes if something more suitable comes along.

The power supply, motors (1.8 Nm) and drivers (MSD542) are from motion control products. I was surprised at how fast the machine can move (I was expecting it to be really slow), but I need to do some proper tests to establish the usuable speeds.

I have connected the drivers, e-stop and limit switches to the PC using a CNC4PC breakout board. My limit and home sitches are mounted on aluminium rails, so they can be adjusted.

I am controlling the machine using EMC2 on an old pentium III computer (I am impressed by EMC2 - it now comes on a live-CD which is easy to install).

The cutting motor is a 850W Ferm laminate trimmer, to be replaced by a 900W Kress router I just bought on e-bay. I couldn't find any small size collets for the Ferm router.

I have a number of things sill to do:

• Re-make the router mounts. The ones I made are too flexible and the router is too high above the cutting bed.
• Make a decent supporting table so I can fine tune the machine and level it out (it is on my Fathers old wobbly dining table at the moment).
• One of the bearings on the X axis is a bit off and should be re-made.
• Tidy up the wiring (it is a mess).
• Try to measure the deflection of the machine (maybe with a dial test indicator or something)

I have posted a build log and some more pictures here

[Check twice!]

I am just getting set up to start a CNC machine of my own the JGRO. I have just finished a thickness sander (my 2ad machine took me 2 tries to get what I really wanted) and now have my eyes set on a CNC machine. My lack of knowledge is more than compensated with the knowledgable people on this site. Looking forward to posting as I go along!

My son and I have started a guitar as well as drums. This was the inspiration that started CNC thing! (inlay)
Have a great day and a better tomorrow.
John

[Glidergider]

Glad I was able to help. Your machine looks great. You're going to have lots of fun. Dreaming up stuff to cut is the fun part too.
Dave

[Check twice!]

I fractured my heel 3 weeks ago in a stupid workshop accident, I am one who believes in safety BUT a decision without thought leads to accidents. The old saying "familiairty breeds contempt" I guess you might say "my stupidity" but will not admit this to my better half. "Shop safety" would be an interesting forum.

I have photos of many of my projects as well as my shop. I am new to forums so still feeling my way around and "learning" more than "speaking".

You have a great day and a better tomottow!

John

[Check twice!]

I have trided to make the blocks out of MDF as the plans call for. I found the MDF to be too soft to firmly hold the pipe in place for the fine tuning.

I did try a piece of birch and seemed much stronger. Ideas or suggestions?

Thanks John

[Glidergider]

Cut the blocks out of HDPE plastic. .75 thick. You can buy it at www.Mcmaster.com HDPE is stronger then wood by a big margin.

[Check twice!]

I thank you for the idea of using HDPE.
I will now throw out the 4 large and 8 small blocks made out of MDF. I have honed my drilling skills, 96 x 13/64".... 8 x 1" .... 4 x 1 1/2" holes, Hum! maybe I should have asked! http://www.cnczone.com/forums/images/smilies/smile.gif

Thanks
John

[NB70]

I used the HDPE plastic (from a kitchen chopping board) for the pipe support blocks (thanks again to Dave for that idea!). I couldn't get 0.75 inch so I used 0.5 inch. I would say that 0.5 inch is too thin: try to get the 0.75 inch if you possibly can.

I have used the machine to cut out some router mounts: it turns out that the new router I bought fits the original JGRO mounts exactly. I added a couple of extra holes to mount a dust hood that I am hoping to make (I'll post a picture if it works). I used CamBam CAM software to generate the G-code.

That's one of the cool things about these machines. Once you have made them, they can make parts to replicate and refine themselves.

Check twice: good luck with the build & hope to see the guitar when its finished!

[Check twice!]

Found this on LV site, I would say it will work??? Thoughts
http://www.leevalley.com/wood/page.a...45&cat=1,43455
Thanks
John

[NB70]

The UHMWPE would work, but it has higher spec than HDPE so it will be more expensive. I think they use if for applications were low coefficient of friction is required (hip replacements, snowboard coatinds etc).

Nathan

[Check twice!]

As I read along I find many mentions of the different grades of acme rod. My question is "what is the minimum/best acme rod to use for my machine?" Any links would be appreciated so I may have a workable knowledge of the steel grades. Is there a "acme rod grades for dummies". I did google it but found advertisments but no real information on differences and uses.
Thanks
John

[Check twice!]

Thanks Nathan

I will likely take the road of least resistance and use LV, I do not require that much UHMWPE for the blocks. My corcern was, would it work and you answered that.

I did find the info on acme rod, looking through past posts netted me this http://www.nookindustries.com/acme/AcmeGlossary.cfm and with this I will have enough knowledge to "make myself dangerous" but I now understand the different types of acme threads and uses (at least for this application).

Life is not a destination, but a journey!
Thanks
John