Building JGRO - questions

[pntbllrsprky]

Ok I have a few questions about building a JGRO.

On the parts list its says cnc_dtl12 www.rockler.com -- --- HOLD DOWN CHANNEL. I quickly looked at their site. What exactly am I looking for?

The on cnc_dtl01 and 02 there is some holes marked thru all, and some that aren't marked that. Does that mean that the thru all are drilled thru both sheets, and the other one just thru the top? (pages 18 and 19 in the pdf)

This is my first machine and my set into CNC. My uncle has a mill and lathe and I am hoping he will help me build this machine. Hopefully I will learn more about machining while working on this.

[HayTay]

On the parts list its says cnc_dtl12 www.rockler.com -- --- HOLD DOWN CHANNEL. I quickly looked at their site. What exactly am I looking for?

CNC_dtl12 Sources:

Rockler Aluminum T-Track

McMaster-Carr T-Slotted Mounting Track

INCRA T-Track and T-Track Plus at WoodCraft.com

The on cnc_dtl01 and 02 there is some holes marked thru all, and some that aren't marked that. Does that mean that the thru all are drilled thru both sheets, and the other one just thru the top? (pages 18 and 19 in the pdf)

All of the holes on CNC_dtl01 and CNC_dtl02 are drilled through all (both sheets). What I did was cut the four 8.250" x 32.500" pieces oversize by about 1.000". I then glued the pieces together to make the two supports 1.500" thick as shown in the two drawings. When the glue was dry, I measured and cut the two supports to the proper size as shown in the plans. After cutting the end supports to size I laid out the hole locations. I then clamped both CNC_dtl01 and CNC_dtl02 pieces together making sure that they were square, flat and the hole layouts were correctly aligned. I then drilled all of the holes that were the same size completely through both assemblies at one time to make sure they were properly aligned. I then separated the two pieces and drilled the through holes that were sized differently in both pieces. It may not have been necessary but it made everything line up much better. I used the same technique for the Gantry Sides (CNC_dtl16 & CNC_dtl17). I hope the above makes sense. Make sure you measure and align the pieces more than TWICE (you know the measure twice and cut once rule) because if you don't and something isn't exactly right you ruin 4, fairly sizable, pieces of MDF!!!

BTW, I used a hole saw set and spade bits to drill the larger holes and it was a total PITA. I more or less burned my way through the MDF while stalling the drill press motor repeatedly. Other people have used Forstner Bits and seemed to have better success. Just a FYI. You may want to give the Forstner Bits a try, I know if I built another one I would.

That's probably more information than you needed but I hope it helps your JGRO build go smoother. And, last but not least, WELCOME to CNCZone!!!

[pntbllrsprky]

lol thanks for the welcome and the help.

I learned this year how do to CAD work, but I was taught differently then how he has everything layed out. I am slowly figuring it out. I probably won't start for awhile (zero cash and time) but I can get started on the delrin pieces (have that at work). And yes what you said did make sense.

[HayTay]

If you haven't already done so, download the JGRO Plans in SolidWorks format (~24.6 MB zipped) and the FREE SolidWorks eDrawings Viewer so that you can get a better look at the assemblies (.SLDASM) and construction. SolidWorks eDrawings Viewer is definitely a 'Cool Tool'. You can zoom, pan, rotate, hide, change views, etc. just like in SolidWorks. One of the 'Coolest' 'Cool Tools' is the ability to right click on an item, or selected items, with the mouse and use the 'Make Transparent' feature to be able to see through those parts.

Oh, and along with the eDrawing and SolidWorks file formats, SolidWorks eDrawings Viewer also allows the viewing of AutoCAD DXF & DWG formats.

[pntbllrsprky]

Thanks again. The plans make way more since now. I can't wait to get this built. I have so many plans I could do with it.

ok I have another question on dtl11. It says flanged bearings and mcmaster. I am putting together a parts list so I can order the parts. What exactly am I looking for. I looked quickly threw the drawings but I am lost. The parts list doesn't give me any dimensions

[HayTay]

Originally Posted by pntbllrsprky ok I have another question on dtl11. It says flanged bearings and mcmaster. I am putting together a parts list so I can order the parts. What exactly am I looking for. I looked quickly threw the drawings but I am lost. The parts list doesn't give me any dimensions

McMaster-Carr Flanged Bearing - Double Sealed 1/4 x 11/16" - Part No. 6384K352 - $5.19 US each

Also from McMaster-Carr: White Delrin Sample Sheet— Size is 6" x 6" x 1/2" - Part No. 8573K1 - $10.13 US each.

I know you're going to ask about this eventually, so I'll give you a 'heads up'. For all of the screws, nuts, bolts, washers and misc. hardware look to Bolt Depot. Good prices, fast shipping, parts in stock and no minimums! Make sure you order at least a couple of extra of each because you'll wind up using them for other things once you get the base table built.

You'll be looking for bearings, too. Either do a search on eBay or go to VXB Ball Bearings. Make sure that you get bearings that are sealed and/or double shielded to keep the dust and chips out of them. Again, order more than you need, without going overboard, as you will probably find other uses for them (like your next CNC Table) .

Happy shopping ,

[pntbllrsprky]

lol I already found the delrin (I have used mc master before)

It was just questions on things I didn't know about. I found 30 bearings on ebay for 17 bucks shipped from XVB.

I am thinking of making the adjusment blocks from delrin also. Is this a good idea?

edit: Ok thanks for the tons of help. I am in luck when it comes to machining because I have access to a mill and lathe.

I have found the 1/4 20 threaded rods on ebay. Should I just order 2 6' sections of it (dollar a foot roughly) then just cut it on my own?

Also I think I probably won't build the adjustment blocks from delrin unless my uncle has some spare material laying around. It would be pretty pricey to do it other wise. Biggest hit on the wallet (besides for motors and controller, which I was planning on hobby cnc kit, unless you have a better idea, I can solder on my own, and I can chemically etch a pcb if need be) is going to be the gas pipe.

[HayTay]

I have found the 1/4 20 threaded rods on ebay. Should I just order 2 6' sections of it (dollar a foot roughly) then just cut it on my own?

Why buy them off of eBay and pay shipping and handling and risk having them bent in multiple places while in transit? You can just pop into your local Home Depot, Lowes, ACE Hardware, Menards, etc. and hand pick the straightest, cleanest threaded rod you can find. You pay a little extra in tax but save on the S & H.

You can make the adjustment blocks out of almost anything that is at least 3/4" thick and solid enough (delrin, cast acrylic, oak , steel, aluminum, etc.) when drilled and tapped to allow the 1/4" - 20 bolts to be tightened to hold the gas pipe without cracking or splitting.

Keep on truckin'. It sounds like your well on your way.

[pntbllrsprky]

lol good point I never thought about that.

I just don't feel like working with a ton of MDF. The more I can make out of delrin the better, since I have that at work, and we have experience in milling it.

[Glidergider]

I just finished making my adjustment blocks out of MDF. I really don't like working with MDF but hey, these are great plans, and I'm giving it a shot. I can change it to Delrin at a later date if I need to.
Dave

[edmond]

I am starting to collect parts to build the Jgro CNC Router, I was wandering can I use 8mm metric stainless steel threaded rod instead of the 1/4 inch versionsand can I also use 20mm thick acrylic to make the adjustment blocks.What about the limit and home switches could I use proximity switches or microswitches.

[Glidergider]

Edmond,
Yes you can use 8mm threaded rod instead of 1/4 inch. How many threads per inch is your 8mm rod? The 1/4 inch rod has 20 threads per inch. I'm pretty sure you will be happiest with a larger number to threads per inch (or cm). On my foamcutter, I use a 3/8-16 all-thread. For my router, I'm going to be using a 10 tpi.
Dave