JGRO questions/Build

[u77171]

I am gearing up to build my very own JGRO cnc. I have been going through all of the threads and looking at the plans. I have a few questions though:
1) A lot of people are milling the lead screw to fit a skate bearing. According to the plan the screw goes through a flange bearing without being milled. Is there a reason why people are milling the screw when they don't have to? I don't have access to a mill so I would rather get a flange bearing and leave it alone.
2) I'll probably get the hobbycnc controller kit to save money. I'd like to get a peek at the instructions before I buy so I can determine if I will be able to build it. Can someone post the instructions?
3) I noticed that some people are using a standard coupler to connect the stepper and some use a Lovejoy. Is there a benifit to use one over the other?

I'm sure I'll have more but that's it for now. I appreciate the help. This is going to be an interesting build. I'll post pictures of my progress.

[silentreaper]

Originally Posted by u77171 ... 1) A lot of people are milling the lead screw to fit a skate bearing. According to the plan the screw goes through a flange bearing without being milled. Is there a reason why people are milling the screw when they don't have to? I don't have access to a mill so I would rather get a flange bearing and leave it alone.

The plans call for 1/4-20 threaded rod as the lead screws, do this only if your finances require it. Those who are grinding down to fit a skate bearing are most likely using ACME threaded rod for the lead screws, I swapped mine as soon as I could afford it, with the 1/4-20 your feed rates will be very low (too many turns per inch).

Originally Posted by u77171 2) I'll probably get the hobbycnc controller kit to save money. I'd like to get a peek at the instructions before I buy so I can determine if I will be able to build it. Can someone post the instructions?

Cant help there I bought the Xylotex set.

Originally Posted by u77171 3) I noticed that some people are using a standard coupler to connect the stepper and some use a Lovejoy. Is there a benifit to use one over the other?

I am using both, standard coupler on the Z, and lovejoys on the X, and Y. The love joys are more forgiving with slight misalignments than the standard.

Originally Posted by u77171 I'm sure I'll have more but that's it for now. I appreciate the help. This is going to be an interesting build. I'll post pictures of my progress.

Just remember this is supposed to be a hobby so make sure you have fun.

That is of course unless you are building your to make money with, then in that case make sure you have fun.

[u77171]

Thanks a lot for the quick response! I'll probably end up getting the 1/2" ACME lead screws like everyone else. In that case couldn't I just get 1/2" flange bearings and avoid milling the screws? As you can tell I am trying to avoid milling them! I am pretty good with wood but I haven't worked too much with metal. I would have to send them out if I got them milled.

The cnc is going to be for fun and a nice addition to my (hobby) wood shop. I don't do this for a living but wouldn't mind picking up some side work if it ends up working out. Do a lot of people end up making money with theirs?

[silentreaper]

Originally Posted by u77171 ....In that case couldn't I just get 1/2" flange bearings and avoid milling the screws?...

That will work just five, the only thing you might have to do is, get some five sand paper or emery cloth to buff down the ACME screws, I had to buff mine down a bit to get them to fit just right on the bearings I am using.

Originally Posted by u77171 The cnc is going to be for fun and a nice addition to my (hobby) wood shop. I don't do this for a living but wouldn't mind picking up some side work if it ends up working out. Do a lot of people end up making money with theirs?

That was my plan but there are a few small tweaks I still need to do before I try making money.

[u77171]

I think 1/2" acme lead screws and 1/2" flange bearings are the way to go. No need to mill the lead screw if you don't have to. Do most people tap the delrin lead screws like the plan suggests or do you buy the screws, especially if you are buying the acme lead screws anyway?

I hope to start the project within the week. I will post pictures of my progress.

[u77171]

Update:
The build started off really slow. My wife and I are expecting twins so I have been busy setting up the nurseries. The good news is they are done and now I get to play.

I spent the last 5 days cutting out about 85% of the parts. I am now starting to put together the assemblies. Tonight I managed to complete the torsion box that makes up the base. I upgraded the internal framing to 3/4" MDF and left the top to 1/2". I used wood glue and a pneumatic crown stapler to hold it together. The staples are 1 3/8" long and made the assembly go really fast with no clamps. I used 1 1/4" drywall screws and glue to hold down the top. The end result is very sturdy and square.

I'll probably end up using 1/2" Enco Acme lead screws with dumpster CNC AB nuts and dumpster CNC couplers for the steppers. I managed to find 1/2" flange bearings at a local hardware store so I won't have to turn down the lead screws. They will just get a nut and washer on either side of the two bearings.

At this point I am very pleased with my progress. It's my first CNC so I am taking it slow. I haven't taken any pictures yet but I’ll try to get some posted tomorrow.