Good afternoon, everyone. Doing some planning before ordering a LEAD machine. I currently have a small CNC (Next Wave Piranha), so I have some experience and have learned a few pitfalls to avoid in planning for the next one. But I’d like input from folks who have experience building larger ones like the LEAD machines. So I may put up a few posts like this one asking for input on various aspects. For the record, I’ve watched the entire build video multiple times, and I’ve read the wiki…all of it. Matt does a great job on the build video. This post concerns the base structure for a LEAD 1510 (15 in the X-axis, 10 in the Y-axis). I don’t like the idea of having to lift the whole machine and get underneath to get access to the spoil board attachment. So this is my thought about configuring to attach it from above instead of from below. I’ll try to include a couple illustrations with this post. The idea is to attach some wooden strips on each side of the Y-oriented 20x40 V-slot, using drop-in tee nuts and M5x40mm screws. Then bridge between those with more wooden strips oriented in the X-direction. Tops of the wooden strips flush with tops of the 2040 V-slot. This will allow me to assemble all the V-slot extrusions for the base, then add the wooden strips, then lay an MDF spoil board on top of that and screw it down to the wooden strips from the top. (I do plan to add a sacrificial spoil board on top of that, so the screws will not be in the way of any bits. More on that in a later post possibly.). At any later time, I could remove the spoil board without lifting the machine, and could even remove the wooden strips, if desired. Additionally, with this much extra structure underneath, I feel like I could get away with 1/4 inch MDF for the base spoil board, rather than 1/2 inch. That would gain me 1/4 inch in Z-capacity. Any comments, criticisms, suggestions? Thx, rink.
Most folks install the standard spoilboard as-designed, and then a smaller, surfaced, sacrificial (eg 1/4" MFD) spoilboard on top of that. The big board provides rigidity, the sacrificial board takes the beating. Sacrificial board screws down to the primary using wood screws, composite nails, etc Also check out T-Rail T-Track 500mm
I did something similar to add additional supports. I cut particle board scraps roughly the width of the 2040, mounted those pieces to the 2040, then used a flush cut bit in the router table to trim it down to the size of the 2040.
Yes, Christian James, almost exactly like that. See illustration below. My plan is to put t-track on top of the base spoil board. Then put strips of MDF between those. It looks like you’ve milled channels in the base spoil board, then installed MDF strips over that. Is that correct? And is your base spoil board thicker than 1/2 inch and one piece instead of three sections? Are you using any actual t-track, or do those channels and overlapping strips serve that purpose? Thx, rink.
Yes, what you're planning is essentially the same thing and probably easier. I seem to remember having sourcing problems for T-track, hence doing without it. My base board is quite thick - about an inch or so. The reason for that is to not compromise the board strength after milling the slots. The baseboard of course adds to the structural integrity of the frame and yes, it is one piece covering the entire frame. As far as the top {spoilboard} is concerned, I believe I used a whole sheet and just milled the gaps which created the slots and the 5 separate boards. All the milling and drilling etc was referenced form the same zero position. The milled base slots and the machined board gaps create the effective T slots - no other parts used. Just a reminder....make sure the base board is surfaced before you fit the T-slot extrusions and the spoil boards
I put in T-slot on mine then put 3/4" particle board strips (76mm wide) between the T-track. I used that 76mm dimension because it divided into widths that "seemed right" to me. However, when I did all the upgrades to this current version using parts from my original (Lead Screw Driven Ox Derivative (850x1500)) CNC build, I also took the lessons I learned about clamping. Sometimes you never have T-slot where you need it. I added T-slot to the original build because that used threaded inserts. I often did not have threaded inserts where I needed one either. So, on this build, I used both. I basically put a threaded insert in between each screw that holds the spoil board strips down to the board below. By using the 3/4" particleboard strips and recessing all the screws holding them down, I can resurface many times before they need replacing. I have been using the machine in this configuration for about 8 months and I have barely damaged the spoil board (other than the Tung oil stain) because I have so many places to fasten the clamps (so no need to screw things down yet) and I also decided to mostly always put my Z zero as the spoil board in my CAM software, That way I always cut through the project without damaging the spoil board. The threaded inserts are circled in green. I already had the strips mounted when I decided to add the inserts so I just made a .dxf file of one strip and made the XY zero the center of the hole closest to the front. Then I put the end mill above where I wanted that to be and set the Work place zero there on the second from the left strip. I then jogged over to the middle of the next strip and repeated until complete. There was a reason I did not do that far left one, but now i can't remember why.
The thin strips were in the drawing originally just to accommodate the hold downs but were never fitted to the base.. I attached a long, right angled straight edge along the left side instead, to use when machining parts longer than the CNC - I just slide it forward when I need my work to extend out from the front of the machine.
Sorry, long post. Thanks in advance for anyone that actually reads it: It seems that folks usually use t-track OR threaded inserts OR vacuum OR tape/glue OR.… But I do intend to use both t-track AND threaded inserts, as @Giarc has done. Below are pics of my current set-up. A Next Wave Piranha with very small work area, only 12”x13” (305x330mm). The stock table was aluminum t-slot with the “bent” hold-downs, as pictured. I chewed through a couple of those as well as a bit of the table itself. Also, that type of clamp protrudes above the spoil board so far that it always seemed to be in the way. At some point, I upgraded to an MDF vacuum table and a shop vac. That was functionally good, but I got tired of having to find ways to cover all the uncovered holes, and it was way loud, not to mention that I had to replace the small shop vac periodically. Also, any roughness or unevenness on the bottom of the workpiece rendered that method unusable. So with some experience and lots of web surfing, I finally upgraded my very small machine to the current set up. It’s 3/4” (18mm) MDF on top of the stock aluminum table, held down with nylon hex bolts/washers/nuts. I milled a numbered grid into the spoil board, as well as some diagonals and circles. Then I bored some holes and drove in threaded inserts which sit well below the surface. I now use wooden hold-downs (I modified a common design), which are held in place with nylon hex bolts/washers. Yes, it was a time investment to put all those threaded inserts in. But it’s a small work area and the payoff is that I can align/clamp/mill almost anything that will fit in that small footprint. And almost no chance of a bit hitting anything other than wood or plastic. I can resurface this board several times, and it’s pretty easy to replace it if needed. This holding method has never once failed and I almost never cut into the spoil board (when cutting through material, I usually zero the Z at the table). And when I set up a job in VCarve, the first thing I draw is a red rectangle inset from the edge of the material by 5mm, which I call “clamp line”. I keep all of the design inside that so I don’t clip any of my clamps. But the couple times I have clipped one, it’s no big deal since they’re wooden. So I will incorporate all of this into my upcoming LEAD 1510. But because it will be much larger, I won’t fill it with the same density of threaded inserts. I will install t-track every few inches and supplement that with threaded inserts in between. And I’ll make some larger wooden hold-downs of the same design. So finally… After thinking through several options and with good feedback in this thread…I think I’ll install the 1/2 inch MDF baseboard as OB has designed (but in one big piece, not three) and bore some holes in it for several threaded inserts. Then top that with t-track and 3/4 inch MDF spoil board strips. Counterbore the 3/4 inch spoil board strips and use nylon hex bolts to attach them to the 1/2 inch base board threaded inserts. Then bore holes in the 3/4 inch spoil board strips and drive in some threaded inserts for additional work holding. That should accomplish everything I want, give me lots of flexibility, and easy to replace if necessary. Maybe I’ll shoot a video of my build process.
I am not going to read more, just going to tell you what I experienced. I spent a lot of time sourcing, then drilling for and fitting, blind nuts. Never used them, in fact that spoilboard is now not even on the machine. Now mostly use tape and superglue, but now and then, like the current job, cutting hexagons out of 38 squares of plywood (4 hex per sqaure), I feel tape would be much more work than needed, so I have drilled the blanks, and drilled the spoilboard, and fitted woodscrews in the waste parts. This allows me to use 6 fixed offsets, G54 through G59, since I had the machine drill the spoilboard at the correct offsets, each piece of plywood will screw down in the right place so that the hexes are cut at the 6 offsets correctly. No carefully alignment of tape for each part etc. as you can see, there are other holes, and other markings, on the spoilboard. I view the spoilboard as a tool, a disposable tool, and when it gets too 'used' I will replace it, I have spare MDF for that purpose. Once you fit those bits of T-track, you will grieve over every scratch on the spoilboard (-: [/QUOTE]
[/QUOTE] Hahaha! Yes, possibly. I’m a bit of a neat freak. I would like know more about those fixed offsets you mentioned. Can you elaborate or send me to somewhere I can learn about it?
Hahaha! Yes, possibly. I’m a bit of a neat freak. I would like know more about those fixed offsets you mentioned. Can you elaborate or send me to somewhere I can learn about it?[/QUOTE] First I positioned and held down the bottom left panel, and setZero for G54. Ran the drill program to drill the piece of wood and about 0.5mm into the spoilboard, just a mark. That first piece of plywood is a template for drilling all the rest, I can clamp 3 pieces to it and drill all 4 holes with a battery drill much faster than I can fasten parts to the machine, there are 38 to drill and cut (with option for more later). Then to set up the G55 through G59 offsets I decided on a 10mm spacing and issued commands as follows G54 G0 X160 ; move right 160mm G55 setZeroXY G0 X160 ; move right again G56 setZeroXY ; move up to next row G0 Y160 G57 SetZeroXY G0 X-160 ; move left 160mm G58 setZeroXY G0 X-160 ; left again G59 setZeroXY Now all 6 WCS systems are set relative to the first one. This is not absolutely necessary, the actual position of each one could vary quite a bit and it would all still work (the reason for WCS offsets existing!) but would be quite a job to repeat. Since I wrote down the G53 coordinates of the first one I can easily repeat the setup. G53 to the offsets, setZero, then repeat above for the other offsets. Homing wins again! Having set all 6 WCS systems I ran the drill program at each one to get marks for the screw positions on the spoilboard then manually drilled each one for the screws. In the image you can see the screws are not all the same size so the pilot holes are not all the same size either, that is why I did not drill to depth with the 3.2mm drill that fits the collet, it would be too big for all the screws. Having screwed down all 6 squares I probed Z on the top center of each one, I know the spoilboard is not flat, we have had 2 weeks of rain and nothing is flat anymore, when it dries out it will go back to 'more flat' (-: Meanwhile I can probe the 6 WCS's, and its not critical on this job anyway, I am leaving 1mm at the bottom of the cut which will be cleared on the router table with a guided bit. This is less of a pain than cleaning off tabs, IMHO. Then I edited the cut program which comes off the CAM in the form header G54 cut 4 hexagons footer and made it cut 6 times header G54 cut 4 hexagons G55 cut 4 hexagons G56 cut 4 hexagons G57 cut 4 hexagons G58 cut 4 hexagons G59 cut 4 hexagons footer The other option is to tape the squares down, probe each one every time (no way I can tape them in exactly the same place) , then cut, repeat. Bit of a pain since the hexagons have 0.5mm of spare space on the sides of the squares so alignment is kinda critical (biggest 4 hexagons I can fit on the 150x150mm squares with a 6mm cutter) Yes, the hexagons are for some sort of board game. Yes, larger raw material would make more sense, customer supplied this. another method would be to fasten fences at left and bottom (just screwed to the spoilboard), snug 1 square against the fences, apply at least 2 clamps on the top and right edges, cut, repeat (first cut probably has to be adjusted to cut the fences correctly too). This would be fine for 2 or 3 parts, but far too much work for 38 parts. As you can see, some cut paths are outside the raw material (orange lines). Designed and Gcode generated from Sketchup 2017. John explains it quite well too.
Wow, a far higher quality explanation than I paid for! Thanks so much for educating me, I really appreciate your time.
