[Charcad1]

This is an upscaled and heavily modified variant of David Steele's 24 x 48 router plans, with numerous size and material upgrades. I think of it as a budget commercial build rather than an expensive hobby build. And at the beginning I need to give a big hat tip to “Devastator's” previous Solsylva upgrade as documented in his thread.

My main goal in this build log is to document the changes and also challenges that arise in upgrading the size, weight and power of this design. And to solicit great ideas from others.

Overview.
Working Area.

The length is set by the maximum working length of a 6' long Acme screw. These are 1/2 - 10 5-start Acme from McMaster Carr and are already on hand. The anti-backlash nuts are DumpsterCNC Delrin nuts. The gantry will be all metal. All linear bearing trucks and components will be steel instead of aluminum. The working width was set by the length of the 80mm x 120mm rectangular t-slot aluminum extrusion beam being used for the gantry beam. This is 52.5" in this case. This was obtained from an metal recycler as junk. Two lengths of 80mm x 80mm extrusion will be attached to the top of the main gantry to establish a gantry height of almost 10”. The Y-Axis pipe rails will sit in the t-slots.

My metric 8020 style extrusion stockpile was obtained at a local metal recycler for $1/lb some years ago. I also scored a fair amount of ½” and 5/8” aluminum plate at the same time and price.
The main table frame is upgraded to a full torsion box bed built from 2x6 lumber and 7/16" oriented strand board (OSB) skins. The top will be layered with 2x4's set 1/2" apart and dado relieved on the bottom edges. This is to form "T" slots for 3/8" - 16 bolts/washers/nuts and rectangular steel bar stock for workpiece hold-downs.

I have done a lot of work with 3/4" MDF slatwall on my wife's various RMU cart mall design projects. I would never try to use this stuff to form a t-slot table top.

The lower reinforcing support shelf is another full torsion box built from 2x4s and 7/16" OSB skins.

The x-rail support beams and legs are made from glued and laminated 3/4" birch plywood. This form of construction is sometimes known as "Glulam". After being trimmed these measure 67" x 6-1/2" x 2-1/4" . The beam tops and bottoms are being capped with recycled steel bed frame rails measuring 1,5" x 1.5" x 1/8". The pipe rail mounting studs, nuts and washers will sit on the steel angles and not directly on wood. The purpose is to distribute the load and prevent the washers from sinking into wood under load. This extends Devastator’s use of individual pieces of steel angle into single pieces running the entire length.

The legs are also Glulam beams and measure 6.5" x 3" x 38". These have welded 1/4" steel plate and heavy steel angle (2.5" x 2.5" x 0.375") feet for mounting industrial casters and also 5/8" - 11 tpi leveling bolts set into tapped holes.

As Devastator noted in his thread, there is no such thing as straight 2x6 framing lumber. What I noticed is that even in pieces pulled from the same bundle at Home Depot there were variations in height and width. This was recent Canadian product - CANFOR - with a July 2015 date stamp fyi. And in my area in SW Florida the larger dimension framing lumber like 2 x 8 nominal is even worse and generally warped. A desire for greater flatness and straightness along with the strength of larger dimensions is what made me use Glulam in this upscaled variant. I think the stock 24 x 48 Solsylva design already pushes stock framing lumber as far as it will go.

Spindle.

Initial Operating Capability will be a Milwaukee 5615-29 1-3/4 hp router motor. This is a single speed hard start. An older US made variable AC transformer will be used for speed control. The final configuration will probably be a 3 Kw water cooled spindle driven by a VFD, probably Hitachi. I am ultimately aiming for milling some steel with this machine in addition to wood, plastic, foam and aluminum.

I am blessed with a 240vac/60a outlet in my shop.

Linear Rails. The initial X & Y axes will use 3/4" ID black iron pipe rails. The Z rails on the gantry will be 1" solid rod. Later when the machine is operational I'll use it to drill a line of vertical holes in 1" precision ground steel rods. Then tap these holes in my drill press using a tap follower and replace the 1" black pipe rails. One obstacle to doing this immediately is getting all the holes drilled truly parallel. The solid rod has to be constantly moved and repositioned under the drill.

Stepper Drives & Motors

Drives will be Geckos or something at least equal in quality. I'm contemplating an X-axis upgrade to a NEMA 34 640 oz-in motor along with an "L" size timing belt and pulleys.


Noise Abatement.

The main torsion box table cells were filled with composite layers of a) 5/8” sheetrock, b) 2” Styrofoam insulation and c) 3” polyurethane foam. This mix completely filled the cells formed by the 2x6 framing lumber. Upon completion the entire machine will be enclosed on the sides and top with 3” polyurethane foam contained in wood & luan framed cells. Noise reduction is a secondary reason for moving to a VFD driven & water cooled spindle.

Sound Absorption Coefficients for some common Materials

This reference lists the sound absorption coefficients of various materials. Note that polyurethane is quite high at 0.95. Home Depot sells 2’ x 6’ x 3” rolls of polyurethane foam for $25 each.
Calculating the wattage of the sound emitted offers an interesting side problem. A good estimate is possible for the energy input to the router or spindle this being in watts (joules/second). Some of these joules will be converted to heat, some to RF and some to vibration and thus transmitted to adjacent air molecules.

Shop Equipment.

Table Saw.

I have a 1959ish Magna 10" table saw I obtained in non-working state for $25 and overhauled. I've added an extension table to this, a shop made rip fence and two table saw sleds. These have been heavily used already. In my limited experience with Glulam fabrication a table saw is mandatory to rip plywood stock to rough dimension and then true up the sides and ends of the glulam beam after gluing. I also do a lot of aluminum cutting on this table saw using 60 tooth carbide tipped blades. I have no sliding compound miter saw or cut off saw. Although these would be very handy it doesn't appear mandatory, unlike the table saw.

Drill Press. I have a Harbor Freight 20" drill press with a t-slot table I bought nine years ago. In this build I've been using both a drill press vise and my shop made drill press table, heavily. There has been a lot of metal drilling already and there will be a lot more, and also thread tapping. There has also been heavy hole drilling and boring in wood.
I think at least a 14" floor or large bench drill press would be the minimum on this particular project. A lot of the drilling and tapping in steel requires correct speeds and technique using cutting fluids. My preferred drills are a set of short double ended carbide center drills normally used in my Atlas lathe. These are more rigid and accurate than standard jobber length drills in steel.
Most salvaged bed frame angle for instance is hardened and tempered. Its great stuff to use. And it will work harden before you know it if proper technique isn't used. I had a few holes there where I had to pull out my cobalt 115 drill index. This only comes out in extreme emergencies when regular HSS is failing and the hole size is different from those available in the standard carbide center drill sets.

Atlas 10F 10x24 metal lathe. This will see heavier use as the project moves into the "metal" gantry and bearing work phase.

Ancient MiG Wire Feed Welder. This was used briefly on the leg feet assemblies. I don't anticipate any further welding.

Hand Power Tools

Most of the metal cutting here is done with a 1990s USA Made Black & Decker circular saw and 7" abrasive metal cutoff blades. A 1/2" VSR Drill/Hammer Drill, two 3/8" VSR drills, two sanders, a 30" belt sander/5" disc sander, a 4" angle grinder, a jig saw and two routers round out the list. I am basically well equipped but nothing elaborate.

The attached pics show approximately the present status. Up to now I've been more interested in working on the build than posting to a thread. I've been photographing as I went along.

Attachment 302036

Attachment 302034

Clearly there has been a lot of cost growth over the basic Solsylva design. But still very economical compared to a full 80/20 build, or a steel tube table.

[manofmanyhats]

This looks like a really stout and well thought out build. I'm looking forward to following along. I'm particularly impressed by the thought going into noise abatement, as that is usually an afterthought for most people (I'm guilty of this). Good luck with it.

[Devastator]

Thanks for mentioning my build! Looks like you've got a good start, I'll be watching this one for sure. Anybody that wants to reference my build thread can click here: http://www.cnczone.com/forums/cnc-wo...-forum-10.html

[wizard]

Not to be picky but a gluelam refers to a specific type of beam. If you laminate plywood you don't get a gluelam, you get laminated plywood instead. Not that, that is a bad thing as I'm sure you are getting good results , I just don't want people walking into a lumber store and confusing themselves or the vendors.