[Timon Cain]

Has any body built a 4'x4' workable area version of the 2'x4' Solslyva design? I just got my manual in the mail and was thinking about enlarging the work area. I was wondering if I could build the y axis out of laminated plywood instead of using alum? The span would be around 57.25". Any help would be great.

[revwarguy]

Hi Timon,

I haven't done what you are describing, but having a 2x4 Solsylva in front of me prompts some thoughts - a 57 in gantry would be much more susceptible to racking, so I would make the gantry side plates longer and add some gussets between the beam and the plates, which would also require the x axis to be longer to keep the same working area as well as add weight. Dual steppers for the X axis might be in order. The Solsylva plans do provide some good info on modification and extension.

As for a plywood gantry, you really ought to see one of these machines in action to get a feel for the forces involved when the gantry starts flying around, and how much they want to bend. Of course, you can always slow it down to a crawl, but then anything complex to cut is going to take forever. It's an engineering problem, meaning you have to make hard compromises with cost, accuracy, speed. A key factor is acceleration, not just rapids, and increasing acceleration is where the table starts to bend and shake. This says you want to keep the weight down on moving parts as well.

Maybe, though, you don't really need the accuracy and a little bit wandering from a plywood gantry won't be noticed - it depends on the kind of things you are going to machine.

The danger is once you've built it, are you going to watch it thinking, I wish I'd have gone some other way? At a minimum, lay out a realistic cost for the plywood version, and a realistic cost for the aluminum one. Shop around for metal or junk dealers, especially any that might be local - they might have a I or C channel that would work.

How you value your time is up to you - some folks love building these things more than they like routing things - as soon as one is built, they're off on another. That's great - If you are more interested in building the table than doing CNC, then taking your time and trying different approaches are what its all about. I know I've learned a lot from this kind of builder right here in this forum, and I am indebted to them. (Thanks!)

However, If you see the table as means to an end, though, and want/need to start making CNC parts soon, realizing later that you have to re-do the Y axis might be a bit demoralizing as well as increasing the cost.

Probably more than you want to know about my machine at www.liming.org/cnc

Good luck on your build, and upload some pictures!

[Timon Cain]

Revwarguy,
Thanks for the reply. The more I think about it the more I am leaning towards the aluminum. I was thinking about using a piece of 2x4 80/20 Tslot. It is suppose to be strong and light and costs around $50. After looking at your site and seeing your C channel it might be worth the extra $50 and go with the C channel. I think it would be less likely to sag.

What do you think of your Bosch Colt? I was going to use a full size router (1.5 HP). Can you cut aluminum with the Colt? How noisy is it?

[revwarguy]

The Colt is pretty noisy for a 1 hp, but I am sure the bigger ones are worse. I bought a refurbished one for cheap, but then I found out that its slow-start circuit won't work with my speed controller. Now, I wish I had gone the extra $30 for the model with the variable speed. :violin:

The 8020 stuff might work great, but I haven't used it. My gantry channel is pretty heavy, the 8020 looks like it might be lighter.

Haven't cut aluminum yet, but I plan to.

[sonicwonder2000]

I've heard good things about the Hitachi M12VC. It is variable speed, suposed to be fairly quiet, and I scored a new one on amazon for $90. I haven't completed my cnc yet so the road test will have to wait till then ...