New Machine Build- JGRO shopping list

[Voyageur]

I am working on my first build. It will be a JGRO-based machine. It will be used for hobby work in wood and plastic. Reasonable performance in terms of accuracy and precision as well as speed is desired with speed being the least important. It’s a hobby machine, not production. I’d like a reasonably nice machine but am trying to keep costs reasonable as well.

Spindle will be either a Bosch Colt palm router or Porter-Cable 690 or similar.

I’m in the process of preparing the MDF and want to get the mechanical and electrical parts ordered. Following is my shopping list with a few questions. I’m interested in any input on this list of parts.


Lead Screws

I’m thinking about 1/2-10 (single start) General Purpose ACME rods from McMaster-Carr. Is there any real reason to go with two start? If I understand correctly it’s essentially for speed. If speed isn’t that critical is there any other reason to go with two (or more) start?

Anti-backlash nuts

I’m looking at dumpsterCNC anti-backlash nuts (AC12101-LN.)

Bearings

I’m looking at the 30 bearing pack from Product - Ball Bearings for Lead Screws and Linear Motion. This pack gets you all of the bearing for the axes plus two for each lead screw.

Motors and electronics

I’m considering one of these packages:


HobbyCNC Pro base - $250 (HobbyCNC PRO Driver Board Packages | HobbyCNC)
Plus $30 for 305oz-in motors
Plus $60 for transformer
Plus $37 for case
Total: $377

or

FineLine Automation (3 Axis Electronics Kit : Fine Line Automation)
3 axis kit - $519
(48 V. 7.3A switching power supply, Gecko 450 4 axis driver, 3 – NEMA 23 380 oz-in motors, cables)


I’m leaning toward the FineLine kit. I have no problem building the HobbyCNC system. From the specs it appears that the FineLine system is a nicer system. Setting aside build time, is it worth the extra roughly $140 for the FineLine package over the HobbyCNC? Is it overkill for my machine?

Any other choices I should consider?


Thanks,

Tim

[kaandemirtas]

Hi,
I did build one as a hobby machine myself. Take my word for it and don't proceed with MDF even if you bought it already.
It is six months now and I am still struggling with MDF issued problems. It is really hard to work with and small inaccuracies will lead to big problems like jammed or problematic axis.
If you don't have a cnc that you can machine MDF you won't be able to get accurate cuts and drills.
What I will do is buy extruded Aluminum and change the whole table and gantry. My MDF gantry is still shaking despite the reinforcements and this is causing a lot of dimensional problems even on a hobby machine. Also as you machine you will notice that MDF does seem durable and tough but will bend a lot under pressure.

Hope you do the right thing and proceed with extruded aluminum. You will use much fewer material than MDF and get a better table.

Best regards,

Kaan Demirtas

[DeadTom]

I have to disagree with Kaan, the JGRO is a great machine if you have access to the good mdf. I built mine with hand tools, 10" table saw and a HF drill press.
I do however think that if you paint your mdf parts it will last a lot longer in humid conditions, where I live it is pretty dry so I did not paint mine and it is coming up on 4 years old and it still is going strong.
Having said all that my next machine will be steel and aluminum as I want zero flex.
I made some modifications to my JGRO and the pics are in the JGRO modification thread to mitigate the flex problem that I was experiencing.
The JGRO is a great get your feet wet CNC router design and the absolute best thing is it is totally free on a free to you website and with plenty of other people to help you along your way.
Tom

[Voyageur]

Thanks for the responses. I'm using MDF for my first machine. It's all cut and ready to go. From all of the reading that I've done it appears that MDF will provide me with the basis for a machine that will suit my current needs well enough.

Any comments on the mechanical and\or electronic components? I'm most interested in views on the motor and electronics packages. Are these good choices or are there other products I should consider?

Thanks,

Tim

[DeadTom]

Tim,
I am only familiar with the HobbyCNC Pro 4-axis setup, except I am running with 200 oz-in steppers on all three axis. All my lead screws are 5/8" - 11tpi single start all-thread from Lowes, keeping them greased with some high-temp bearing grease. It's not perfect by any means but it has cut alot of stuff for me with little to no trouble at all.
The HobbyCNC Pro board works fine for me no complaints but then again that is all I know. My new all metal machine will probably use another setup from them again.
That bearing pack looks as good as any and it includes the support bearings for the lead screws, very handy.
Keep up the good work,
Tom