[justin22885]

im wondering what materials an accurate CNC router could be made of?... MDF, steel, aluminum, HDPE, what about wood, or a large thickness plywood? (like 1 inch?), would it be possible to use these materials as well, and still achieve the same accuracy as an MDF machine using similar designs?

has anyone built a machine of this size out of rectangular tube steel welded, perhaps with tube or plate steel gantry? if so.. what did the steel cost you to build it?... id assume oversizing the steel frame, with some cross braces of slightly smaller diameter to give sort of a set in area to lay a piece of MDF or plywood for the table would be the way to go... weld on the angle iron rails and from there it comes down to gantry design... im going to the hardware store this week to check prices on square tube steel, small diameter i beams, and plate steel to get an idea of what a steel machine would cost... would yield a much stronger machine than mdf or plywood, and might not cost too much more.. so it could be worth it (if you have access to a welder)

if i cant do that im thinking of making the table frame out of 4x4 wood, braces with 2x4 wood, with a 1" thick plywood gantry...

i just dont think anyone anywhere near me carried MDF, so im keeping the options of alternatives open

im looking to build a machine with 48x24 inch travel, i believe that short, leadscrews all around should do fine... i probably wont need to use a chain driven X axis until i build a machine with a 4x8 foot machine later...

so im thinking of using a design SIMILAR to joes.. but not exactly... i think usnig fully supported angle iron rails for the skate bearings to slide on might be better, and easier to put onto the machine

extreme precision is nice... but really not as important for what ill be using the machine for as other things people could use them for, im a luthier, so ill be using it to cut wooden guitar parts which will still need to be sanded and refined anyway

[degreaser]

Here's one with which I'm in the very early stages of fabrication. Table size is 66"x42" with 8" nominal Z axis travel. The base is being built from 2x2x3/16 steel tube. The router itself is 2x2x1/4 and 2x4x1/4 tube and lots of 2x1/4" flat bar. Motor/bearing mounts and the Z axis are constructed of 6061 aluminum. Completed it will weigh in around 1000lbs. Gantry weight will be around 120lbs. The X and Y axis are #2 v-bearings on 3/4" angle, the Z axis is an ebay special 20mm THK linear bearing. I'm using 5/8" Roton ballscrews with dual preloaded ballnuts and nema34 servos with 4:1 belt reduction. The router will consist of welded sub-assemblies which will be bolted together. The base will be nearly 100% welded. At some point I'll upgrade the X and Y axis to THK or equivalent as my budget permits.

I haven't started a build thread yet. Soon. Gotta make the garage presentable for photos . Right now I'm making parts and drilling countless numbers of holes for the various router frame sub-assemblies. I'll fire up the tig when I get most of the cutting, drilling and tapping done.

As far as getting materials, here in Reno I get steel from PDM Steel. They have outlets in California as well. Forget the hardware stores as the markup will be 400% if not more and your selection will be very limited. Find a local steel supplier. The steel for this build was a little over $1K including cut fees.

Building a Joe's 4x2 hybrid would certainly be cheaper and a whole lot easier. Personally, I like steel

[justin22885]

well ive decided to use MDF for the first router.. just a really cheap, simple build... my second router will be a small one, not a tower gantry but one that sits on elevated walls, with a sunken table, itll be for doing steel mostly, but my third one will be a steel constructed much, much larger table, and id really like to use the gantry design in your drawings.. i like it

[ger21]

if i cant do that im thinking of making the table frame out of 4x4 wood, braces with 2x4 wood, with a 1" thick plywood gantry...

A 1" Ply gantry might be too flexible, and you'll probably get a lot of warping with 2x4's and 4x4's.

[beone]

Mine is all 1/2 ply torsion boxes. working great after 2 1/2 years
Dave

[degreaser]

well ive decided to use MDF for the first router.. just a really cheap, simple build...

I would imagine you've probably seen it but there's a very nice example of an MDF router here: http://www.cnczone.com/forums/showthread.php?t=68771

[justin22885]

that is a really nice MDF router... i plan to make one like that eventually to replace the one i have now, but ill use plate steel for that future build.. the one ill build first i might use a similar gantry design but a smaller table... should be able to make it out of 1 sheet of MDF

was this done with a single 4x8 sheet of MDF?

it would be PERFECT if the router could travel a full 4x8 feet

[justin22885]

i really liked the machine degreaser showed me.. it gives me some ideas im going to incorperate into a much more simpler, yet far less aesthetic design...

difference is ill probably use a chain drive for the X axis, and 3/4 inch plywood for the table, and possibly a 4x4 pine frame with legs with 2x4 cross supports under the table.. the 4x4 frame should give me a bit of added width, allowing the machine to travel a full 48x96 inches... so it can carve an entire 4x8 foot sheet of material....

yeah, that sounds best

[laldrich10]

I am going to use 8020 to start. Its the industrial erector set. It should be easy to get every thing straight and smooth opperating. It may cost a little more but will be a lot simpler.

[degreaser]

http://www.finelineautomation.com has a 2'x3' router kit based on 8020 for a very reasonable price. It looks like a very quick way to get something up and going. It's offered by a couple of guys here on cnczone.

[justin22885]

theres a website.. forget what it is.. but it takes you through all the steps neccessary to build a very simple CNC router, even shows a nice chain drive mechanism... im going to build that much simpler gantry, but support that gantry with the Y axis from the other forum thread, and widen it out to cover a 9x5 table, giving me an 8x4 cutting area

the table will be 3/4 inch plywood, cross braces about every 8 inches under the table, and probably an MDF gantry, depending on the cost

since this will be a rather.... long machine for leadscrews, im either going to use a chain drive mechanism (which works a lot like a rack and pinion, but it walks along a chain)... or that rotating nut design in the link degreaser first provided... either way it looks like the X motor will be attached to the gantry

[justin22885]

thing is though.. ive decided to make a plywood base frame, well supported, MDF table, and MDF gantry for a router table with a 4x2 foot travel, since im a luthier, guitars are my first priority, and then i can take the time and profits to make a much, much nicer router of 4x8 size since id be able to use the origional one to cut better, more elegant pieces of wood, have more time to design the specifics of the rails, drive mechanisms, and solidworks the entire project of my own design...

but first, ill just do a simpler, easier, much cheaper 4x2 plywood/mdf design, and after that im doing a small 3x2 or even smaller 2x1 design made of square tube and plate steel.... but without the tall gantry.. the kind with the walls where the gantry rides on top of those walls, since its a much stronger design, and machine 2 will be for steel :-D... .number 3 will be the 4x8 model

[justin22885]

since mine will be smaller than some of these, im going to go with 3/4 inch plywood, a basic gantry design, and im going to build a well supported plywood body 60x36x6 inches, with a total router travel of about 48x24 inches, with a removable 4x2 foot section to replace the table in the future if neccessary.. well supported underneath with a plywood board running across about every 6 inches

total travel should be 48x24x12 inches

since this will be a small, wood and soft material only router, i think threaded rod and a nut would be cheapest and easiest

with the hardware store here i should be able to get threaded rod in bulk.. and have it cut for me to 5, 3, and 1.5 foot lengths, i can probably find a threaded nut i could literally just screw into the bottom of my gantry... so i dont think ill need to make any boxes to hold that.. all simple ****

2x sheets of 3/4 inch construction grade plywood 4x8 foot size
30 feet of angle iron 1 inch apart at the feet, hardware store will cut to the lengths i need for me
1x router motor, 1 1/2 or 2 1/2hp, undecided
24x skate bearings
various nuts and bolts
10 feet of threaded rod, cut
some couplings to mount the rods to the motor, bearings for the free end of the rods
bulk electrical wire in various colors
some tubing to hide all the wires together nice and neatly
one 3 axis hobby CNC controller
and the power supply components

if i buy a used router on ebay for the motor, get the drive motors surplus, im looking at like $300 for the build, and itll be plenty accurate for shaping my guitar parts

found where i can get inexpensive 2 1/2 and 1 1/2 horsepower routers to use the motors from...

just one question, on a machine that will be doing soft metals and wood... would the 1 1/2hp motor be sufficient? or should i step it up to a 2 or 2 1/2hp motor?

as far as drive motors go.. is there any specific features or certain amount of power i need to look for when selecting drive motors?

[sonicwonder2000]

I am in the midst of building an all-metal router and it is quite a bit of work; especially if you are more comfortable working with wood than metal. For your purposes, I would think a wood or mdf router would suffice completely. One comment I would make, however, is consider using ACME threaded rod instead of all-thread. It is much more efficient and you will be able to get higher cutting speeds which will be important for you since you are using this in a professional environment. I would forego the chain drive idea and go with either ACME threaded rods or belts; I have seen chain drives used in plasma routers where heat and sparks are an issue. Good luck on the build and take some photos!

[justin22885]

well i have to go for cheap right now... speed isnt a major issue, if it takes hours to cut a guitar body and neck, im fine with that.. but first priority is cost, without sacraficing too much on accuracy

what does a 5.5 foot, 3.5 foot, and 2 foot acme rod cost?

[degreaser]

what does a 5.5 foot, 3.5 foot, and 2 foot acme rod cost?

It depends

Take a look here: http://dumpstercnc.com/ Look at the ACME components section. From there you will find McMaster and Enco part numbers for a variety of acme rod types. You can price them at mcmaster.com and use-enco.com

[justin22885]

hmm... i guess it says i can get a 12 foot length of 3/8x12 inch acme rod for $16? is that right?

anyway, if $16 is real for the 12 foot length... yeah, ill go for that, since 12 feet is enough for all three axis with a foot longer than needed per axis.. so i could fit the rod, and cut off the excess, etc... i guess ill order 12 feet, or two 6 foot pieces of acme threaded rod... but i bet my hardware store will have a nut that i can screw to the bottom of my gantry

ill screw the nut to the gantry first, making sure its centered... drive one of the scrap pieces of rod through it... then slide my gantry all the way forward and all the way back with a little paint on the ends of the scrap rod so ill know exactly where to drill the holes for the bearings to hold the rod

[justin22885]

aaah.. a platform nut.. thats what its called

hmm, i may still get normal threaded rod from my hardware store because it would be more convenient and my plan is to later upgrade the machine to ballscrews.... until then, any idea what the best size and thread rate would be for a CNC machine?

also, im still looking for inexpensive stepper motors for my project, wheres the best place to get used or surplus stepper motors such as those neccessary for CNC work?

[lumberjack_jeff]

Check out Mechmate for a large-format steel cnc router.

I'm building one now. My electrics/electronics are done. The table, gantry and y-car are all welded and rolling. The plans are extremely well-done, and I've found the fabrication to be well within my capabilities and I have extremely limited fab experience.

It is very heavy-duty so it requires a robust drive mechanism, Nema 34 steppers minimum, ideally fitted with a gear reduction.

People report an average cost to build of about $4500. Not cheap, but it's designed as production quality.

http://www.mechmate.com/

[justin22885]

looks like my local hardware store has 4x8 sheets of MDF for $27 each and about $9 for a 4x2 sheet

running the math through my head it should be eonugh to build the really strong table i want, well supported, 2 inches thick, and an all MDF gantry.. so thats the route im going... angle iron seems to be expensive here.. $40 for all the pieces i need... so i may order that online if i can find it cheap enough... and $8 per 6 feet of 1/2 inch threaded rod... i would need two of these... im thinking i should be able to do a full MDF machines rolling chassis and structure assembly for $100... which doesnt include nuts, couplings, bearings for the rod, motors, wiring, the controller, or the PSU

if i get surplus motors, make the controller and the power assembly, i think i can do the entire machine for $300-$350

im going to get a 2 or 2 1/2 horsepower non plunge type router from ebay... used, and either mount the entire router face down on a platform, or gut the motor from it, and thatll act as my router motor, can get those for like $30, motor working well