CarveOne's Solsylva 25x37 Router Build

[CarveOne]

Hello fellow builders and lurkers. I've been knocking around these forums for a few months while deciding which router design to go with for my first build. I have previously built my own redesigned version of a manual duplicator based loosely on the Copy Carver. A photo of it is included below.

However, I also wanted to build a CNC router - even as I was working on the previous machine. The machines have distinctively different applications and similarities of course.

For various reasons I decided to build David Steele's 25x37 dual lead screw design. One of the reasons is the ability to raise the machine easily for carving on thick objects. I chose red oak for the wood parts mostly for the stiffness and for the looks, being somewhat of a wannabe woodworker as well. The side rail and y axis boards are laminated 1x4 boards to arrive at the equivalent of the 2x4 boards specified in the Solsylva book.

Current status and changes from the plans book - The table frame is completed and the y axis gantry is completed except for addition of the end plates and trucks. All of the oak blocks for the Z axis have been cut but not drilled. I made the stepper mount plates from 1/4" aluminum plate. I'm currently working on the z axis side plates, which will be made from 1/4" aluminum plate. I have cut the x axis bearing support blocks from Purpleheart but this may change to 3/8" aluminum if it is necessary. The lead screws are going to be 1/2" everywhere possible. I'm not sure at this point if the leadscrews will be allthread or acme thread. I made some 3/4" x 1/2" thick round nuts to go inside the EMT tubing. The nuts were installed in the tubing and a length of 1/4-20 allthread was blue Locktited in place in the nuts. This allows me to hold the tubing and channel in place on the side rail and gantry with a nut and the assembly is easy to remove if necessary. I installed a piece of 5/16" thick by 7/16" wide oak to go inside the channel so that spreading of the channel walls won't be an issue if the mounting nuts have to be torqued a lot.

I hope you find the changes to be entertaining and worth following. Your comments, suggestions, and questions are welcome.

CarveOne

[grahamshere]

Hey carveone, looks great so far, I seen your thinking on which lead screw to use, Dont even think about it, get the acme 2 or more start, youll only want to change it right away if you use the allthread, take it from me and many others that did the same, I only have the 1 start but my next machine will be more, davids plans are awsome and can be adapted into other designs. Have fun with the build. Graham

[CarveOne]

Thanks Graham,

I already have the 1/2" allthread and couplers on hand and have determined from email discussions with rc_flyer that acme is the way I want to go. He is in the middle of upgrading his machine now, and I'm continuing to build my remaining machine parts until I can get some money together with sources for an order.

I found that the 1/2-13 allthread from Lowes builders centers (US) is close to the correct diameter and has a rough surface, but the couplers they sell for the rods are too tight. Running one of the rods through a threading die cleans it up a little, pulling out small chips and smoothing the surfaces but running a 1/2-13 tap through the coupler pulls out long strings of metal. Running the recut coupler on the recut rod is now pretty smooth but it has too much freeplay.

Running the recut coupler on a non-recut rod is also smooth and has less freeplay. 13TPI is going to be too slow with my 425 oz/in stepper kit from Xylotex anyway, so I'll go with the acme rods, find the bearings that are needed, and get the anti-backlash nuts from DumpsterCNC.

Oh well, maybe the 1/2-13 rods will make good tomato stakes next spring or find some use in my next project......


CarveOne

[grahamshere]

I have the same setup as you with the 425's I can get good speed with the y and z axis but the x is not good, 30 imp which I believe the problem is with the belt. I had the y and z axis going 90 imp and could have gone faster but the machine shakes due to whip, so when you get your acme make sure there straight. I think the pull from the belt causes the stepper to go off tilter or somthing, It might be a good idea to use another gear or somthing to drive the pully that drives the belt if you know what I mean lol, think I lost my self on that one lol. What will you be doing with the machine once its done?Oh make sure you use a good computer, over 1 ghz, I used a 667 mghz and it ran slow so I hooked up the pent4 and wow what a diff. Graham

[rc_flyer]

Hey guys..

just put up a thread to deal with the 1/2" acme upgrade on my year old Solsylva router.. Figured a seperate thread made sense since it will help answer a bunch of upgrade issues..

ALSO.. Does anybody out there either know anywhere that sells 12" lengths of 1/2"- 4 or 5 start acme lead screw, without a $60 minimum??

OR does anybody have about 12" left over from a build or upgrade?? Budget for the router is about empty, since we are shopping for a new printing vinyl cutter for my wife's biz...

Don
www.eurekaaircraft.com

[CarveOne]

Graham,

I'm concerned with the whipping also, and will very likely go with rc_flyer's upgrades that he is doing as we speak. (There'a a few true leaders and there's lots of followers, eh?) Meanwhile, I'm just making the other parts I need anyway.

Speaking of which, I didn't make nearly as much progress as I had hoped this weekend. Making just eight parts took the few hours I had available. See photo below.

I will be using it to make birch plywood and liteply parts for wind tunnel models and possibly some grips for 1911A pistols. Maybe some 3D carvings for woodcraft projects. Anything else that might repay the expense of building it.

CarveOne

[pumelloman]

Hey CarveOne,
Wow looks pretty spectacular! Even though you say you work slowly it's a lot faster than me....and your workspace is neater/bigger than mine too... looks like I'm losing haha.

I was interested in the upgrades you were talking about, seems like you're going to 1/2" leadscrews haha, and it seems like you must grow a lot of tomatoes haha, (I ended up using the Conduit to bar my windows at home from possible home invasion, the tomatoes will have to wait I guess). I'd like to upgrade to ACME as well, probably 2 start as Graham was suggesting, but I guess it'll be a project for later (CNC + Uni = no money/debt). Is it true though that the torque would be a lot less than with the 1/4"? I guess the ACME ones will be a lot more efficient though, that might make up for some of the power transmission losses.

I had also looked around for anti-Backlash nuts too, and on DumpsterCNC. I noticed somewhere that an anti-Backlash nut doesn't look that complicated to make if you have a CNC already.... It just seemed like you needed to cut 2 pieces of plastic, make them interlocking, then drill a hole through them and tap it. After that, have a spring in the middle that pushes them apart, compress the assembly, and thread it onto your leadscrew. Sure it all "sounds pretty easy" but I'm probably missing a critical detail that makes it really hard to do.... Might try it out later this year in the University machine shop, might need to use a mill to do some more precision stuff than what my CNC will be able to do (seriously worried about slop in the assembly...some shotty incompetent university student was building my machine so I dunno.... ha. ha. ha.).

I liked your round nuts, they look pretty kickass. Is that steel? Should be pretty good and won't rip out of the EMT, unlike those threaded holes, looks sketchy. I also experienced a problem with the rails spreading when I tightened the nuts a lot...is the oak piece used as a spacer or as a reinforcement? If it's a reinforcement how are you attaching it to the channel?

What software are you using by the way, for interface to the controller card (I have the HobbyCNC one)? Mach3? I also got my hands on MasterCAM V9 tutorials and MasterCAM X2 but I have yet to try that out. How will you be going from Solidmodel to G code?

[rc_flyer]

pumelloman,

Don't worry about the tapped holes in the conduit, or the spreading channels. Mine has been running for about a year with no problems with either. I did use steel tubing for the rail and gantry supports, which might have made a difference. I also used allen head bolts instead if hex head bolts to hold the conduit in place.

It seems by some tests I have done here, that people having problems with the above are tightening the bolts a lot tighter than needed, since very few people will be using a torgue wrench to tighten them down. When tightened properly, not 'tightened till the bolt won't turn no more', and using lock-tite, mine have not budged or moved in a year. Tighten them till they are firm, and they will not go anywhere. My test showed that when using a wood frame, it feels looser at the same torgue settings than it does using metal supports. Flattening out the top of the holes, so the washer doesn't have to bend will also help tremendously when tightening them down. That give as the washer is bending is very deceiving on how tight it is.

You will find that David's designs are the best out there, from my experience. They work well when built as described, but lend themselves to upgrades VERY well. His design would make a great all metal machine, with 4 or 5 start lead screws, solid rod instead of conduit, etc. is just depends on what you want to spend, and your building skills. I have been slowly upgrading mine as it makes me money. As time goes on, I'm sure it will be an all metal, kickass machine, that grew as my uses (and spending) dictated. Most other designs wouldn't do that very well. I'm sure if money were no object, A shop-bot or equiv would be great, but knowing me I would have went the Mechmate way then, for the building experience.

Good luck..

[CarveOne]

pumelloman,

rc_flyer is correct about the threads in the conduit holding the rails just fine as David designed it. I always find some excuse to overbuild everything I do. Bad habit I learned over the years.

The round nuts are made from 3/4" hot rolled steel bar cut into ~ 1/2" thick sections. The 1/4-20 threaded holes go all the way through. They are very easy to install by sliding them into the conduit with a dowel while holding the conduit with the 1/4" clearance holes facing upward. The nuts are wide enough that they won't spin around while running a section of Locktited 1/4-20 allthread into it. If the allthread is not tightened against the opposite wall of the conduit the allthread is easy to align with the holes in the wood side rail.

The 5/16" x 7/16" wood strip is just spot glued into the bottom of the aluminum channel with Tightbond II adhesive. It is there to limit over squashing of the channel walls if I have any trouble with conduit flexing sideways from router bit side loading. It's not necessary, as Don says, but overbuilding it now is better than having problems later and having to mess with realigning the x axis rails again.

I will be buying Mach3 and have TurboCAD 12 for drawing parts. Hopefully the dxf file export will import ok in Mach3. If not, then something else will be sought. Can't afford any high priced CAD packages. Will have to deal with the software issues when the machine is ready to run.

CarveOne

[CarveOne]

Made a few more parts for the gantry last evening and this morning. Working with the red oak is nice. The blocks are are not showing any tendency to cup after three weeks since I cut them to length, and there has been no finish coats applied yet.

Pardon the wierd looking photo. It's a top down view with a black rubberized mat for a background.

CarveOne

[grahamshere]

Hey carve one, as long as your wood is nice and dry before cutting every thing then it wont cup,warp or bend,just dont let any moister get in .
Ive noticed a few ppl are a bit worried about losing torque using 1/2" acme with this machine, dont be, theres tons of torque, couldn't stop the machine if I tried. Forgot to turn the router on once and it almost ripped the machine right off the table which is all screwed down, Ive stalled the router a few times, its a PC laminate trimer. So lots of torque. Graham

[CarveOne]

grahamshere,

This premium grade oak 1x4 lumber is expensive, very dry, and I bought it for the additional rigidity and good looks, and have not had it warp on other home projects I've used it on before. Where I normally have to buy pine lumber the stuff is not at all stable and I wouldn't use it for building one of these machines. Making the frame and gantry out of steel might have been less expensive.

I don't think the 1/2" leadscrew concern is valid unless it happens with rough poor grade allthread rods and/or threaded couplers that are cut too close to the minimum diameter. I could believe that properly sized 1/2" althread and couplers could have a little more frictional drag than the 1/4" or 5/16" allthread and couplers due to the larger mating surface area. This is one reason I ordered the 425oz/in steppers. They will have the additional torque at lower speeds and still have enough torque at the higher speeds (I hope). I tried running an allthread rod through a 1/2-13 threading die to smooth out the rod, and running a 1/2-13 tap through a coupler to eliminate the tight spots, eliminate binding, and it reduced the drag to a very tolerable level. With the anti-backlash nuts this rod will work fine except that the rod has a small serpintine spiral in it that I can't tweak out of it by hand.

rc_flyer is using his machine again now that he has completed his upgrade effort (is it ever really completed?). He seems pretty happy with his new 1/2" rods so far. I don't recall him complaining about x axis rod whipping either.

Gotta get back to making some more parts. Later guys.

CarveOne