[wizard]

Nice progress!

As to your ballast, if it is wood or plastic you might want to reconsider the idea that it is ballast. To others it would be kindling or a fire hazard. The last thing you want to have happen is your machine catching on fire in the middle of a run while you are doing something different.

As to the diagonal reinforcements that is a very good idea. However the don't need to be plywood panels and frankly such panels can get in the way. You may want access to the machines underside from time to time. So consider lesser braces or removable plywood panels. I stress removable because I have a tendency to glue everything together when working with wood. The other option would be to cut "windows" in the plywood where you would most likely need them and glue everything together. A full sheet of plywood would do much to stiffen up the long sides of your machine.

If you don't do plywood on the long side I might suggest vertical stiles on the long sides in the center. You would still need bracing for racking but a simple vertical post would have a significant impact on that long stretch.

Thanks for the kudos, and from one Paul to another Paul I can say that it's never to late to make changes, heck the BIG 3 do it on a daily basis. Diagonal braces on 3 sides are easy, that way they stay open to collect tons of dust and debris, which I'm going to call free ballast. However, I do want to keep the front open for placement of my computer and such. I'm going to try and get a weight for the base frame tomorrow just to satisfy my curiosity as it has now become a 2 person task to pick up and move.

Paul

OK, I just weighed the base and it tips the scale at 192# and from this point it can only get heavier. Now I have to devize dolly to move the thing into it's final resting place when completed.

[JerryBurks]

OK, I just weighed the base and it tips the scale at 192# and from this point it can only get heavier. Now I have to devize dolly to move the thing into it's final resting place when completed.

My machine is of similar size (36x48" table) and I also have a similar wooden triangulated stud frame base plus a torsion box table top. Total weight of the completed machine is over 500 lbs. That base is rigid enough that I have the whole thing on 4 sturdy casters to move around as needed. I don't even set the caster brakes anymore when operating the machine. The reaction forces of the moving gantry make the whole machine wiggle maybe 1/2" while operating but it does not really matter. As long as the table and base don't deform it does not affect the accuracy.

[plcamp]

Nice progress!

As to your ballast, if it is wood or plastic you might want to reconsider the idea that it is ballast. To others it would be kindling or a fire hazard. The last thing you want to have happen is your machine catching on fire in the middle of a run while you are doing something different.


As to the diagonal reinforcements that is a very good idea. However the don't need to be plywood panels and frankly such panels can get in the way. You may want access to the machines underside from time to time. So consider lesser braces or removable plywood panels. I stress removable because I have a tendency to glue everything together when working with wood. The other option would be to cut "windows" in the plywood where you would most likely need them and glue everything together. A full sheet of plywood would do much to stiffen up the long sides of your machine.

If you don't do plywood on the long side I might suggest vertical stiles on the long sides in the center. You would still need bracing for racking but a simple vertical post would have a significant impact on that long stretch.

The ballast comment was my attempt at levity, in reality I would never let wood dust and debris collect on the lower shelf of the machine base. This is my intended computer location, however if it is really a dust collector I may have to move it to a more favorable location.

The bracing is complete as shown in the picture and will be open, no sides. This design yields strength yet allows access for cleaning.

[plcamp]

My machine is of similar size (36x48" table) and I also have a similar wooden triangulated stud frame base plus a torsion box table top. Total weight of the completed machine is over 500 lbs. That base is rigid enough that I have the whole thing on 4 sturdy casters to move around as needed. I don't even set the caster brakes anymore when operating the machine. The reaction forces of the moving gantry make the whole machine wiggle maybe 1/2" while operating but it does not really matter. As long as the table and base don't deform it does not affect the accuracy.

I'm sure my machine will approach or exceed the 500# mark as the remaining sub assemblies are added. I will develop a dolly to assist in moving the completed and tested router to a final location and any subsequent relocations that may take place. So at this time casters are not part of the plan.

[Mountaincraft]

on your gantry and risers, why not use MDF instead of plywood?... much flatter, denser, straighter and less prone to blowouts when machining/cutting... It is much less prone to warpage.. and like Gerry said, using a torsion box design will give you 'much' needed rigidity...

Plus you can use the leftovers to carve stuff in....

Note that I said MDF, not Particle Board..

[plcamp]

on your gantry and risers, why not use MDF instead of plywood?... much flatter, denser, straighter and less prone to blowouts when machining/cutting... It is much less prone to warpage.. and like Gerry said, using a torsion box design will give you 'much' needed rigidity...

Plus you can use the leftovers to carve stuff in....

Note that I said MDF, not Particle Board..

I know there are many routers running and doing quite well that have been fabricated from MDF, however my entire design is based on plywood. MDF could be a viable option if I did not have $155 invested in Baltic Birch due to arrive this week. The Baltic Birch is manufactured from solid wood cores unlike standard ply with layers of filler wood and internal voids.

Density of MDF is often 2.3 to 3.0 lbs/sq ft depending on the resin/fiber ratio. Baltic birch plywood is 2.6 lbs/sq ft so the fabricated weights should be approximately the same. Yes, there will probably be difference in the surface finish as one product is pressed, and the other is sanded.

[plcamp]

The wait for the birch plywood to arrive is over, it found it's way to my door August 22nd. Layout of the router parts is critical because this ply is manufactured in 5' x 5' sheets and care must be taken to minimize waste. At $99 a sheet delivered I'm using every square inch that I can. Rough cutting of the components is WIP, sorry no pictures yet. I have not however just been sitting idle while my saw cools off. I designed my dust shoe which will be high on the priority list once the router is running and tested. Dust shoes as we all know are a must have item if one is to attempt collecting the debris generated by a router. The attached pics show my design......Of course the brush strip and hose are not shown in these pictures.

FYI-The shoe will be manufactured from laminated 1" MDF and at the moment wall thickness on the vacuum hose attachment is 0.100" thick. This may need thickening depending on how well it machines, that's why it's called R&D.

[Devastator]

I know there are many routers running and doing quite well that have been fabricated from MDF, however my entire design is based on plywood.

Using MDF takes extreme measures like building bulky torsion boxes to achieve stiffness. I laminated plywood together to make stiff beams for my machine and don't regret it: http://www.cnczone.com/forums/cnc-wo...lva-build.html

Every time I consider using MDF for structural applications, I end up changing my mind.

My first router mount looked a lot like your design with the two rings. I upgraded to a full length clamping block and it made a big difference in the amount of torsion that I could impart to the router.

[plcamp]

The Baltic birch ply was always my choice of material for a wood fabrication. I had first designed this router as a 8020 machine, however the $3k+ material cost quickly changed my mind and direction to wood. This will be a hobby and small project machine and I just could not justify the cost of the 8020.

At this time the only MDF planned for use on my router will be the dust shoe and spoil board. The router clamps are also fabricated from Baltic birch and should they prove to be 'weak', a laminated block would be an easy addition. Now that I have had a moment to reflect on your comment about the router clamp, I'm going to follow your lead and make it a 1 piece lamination instead of 2 separate pieces.

[plcamp]

Modified router mounting clamp.....

[Devastator]

I had first designed this router as a 8020 machine, however the $3k+ material cost quickly changed my mind and direction to wood. This will be a hobby and small project machine and I just could not justify the cost of the 8020.
.

A properly engineered wood machine can be more rigid than 8020 especially if you attach some structural steel in key areas like the gantry to combat twisting. It also dampens vibration much better than 8020. New router mount looks great, you won't regret it.

[plcamp]

A properly engineered wood machine can be more rigid than 8020 especially if you attach some structural steel in key areas like the gantry to combat twisting. It also dampens vibration much better than 8020. New router mount looks great, you won't regret it.

Thanks, the router mount was an easy change and I was actually thinking of putting a 2" x 2" piece of steel channel on the inside of the gantry.

[Devastator]

Thanks, the router mount was an easy change and I was actually thinking of putting a 2" x 2" piece of steel channel on the inside of the gantry.

That would be a good idea. I'm designing a 48"X 48" machine in my head to replace my 24" X 48" and the machine I end up building will be about three times as bulky as your design. If I were you, I'd double the thickness of the L uprights, center the Y leadscrew on that axis, seriously beef up the motor mounts/bearing mounts on the X. Cantilevering them out there like that will require the use of steel IMO. Otherwise when it changes direction, those mounts will flex. Also, if you could tie them together on the outboard side of each leadscrew that will help, because when you preload the screw to take out backlash, those cantilevered plates will have a tendency to pull inwards. Wood just ain't gonna cut it there without a redesign IMO. If you could change the L uprights to triangles, that would help too.

And making the gantry beam one solid block of wood (laminated beam) or a torsion box.........I'm going with solid on my design. With wood think beefy....Like this:http://www.cnczone.com/forums/cnc-wo...tarted-40.html One of the better "non metal" builds.

[plcamp]

Well I have pieces and parts for the gantry, the mockup looks good and the 'Y' axis rolls freely. I will begin on the gantry final assembly this weekend and then its on to the 'X' axis carriage followed by the 'Z'. I wanted to paint the base today, but heavy storms here in Indiana has driven the humidity out of site so that task will have to wait until a more favorable day for paint to dry.

[Devastator]

Making some progress! Your gantry being supported solely by the edges of one sheet of plywood is a gutsy move. Probably be fine, but long term stability might be worth keeping an eye on. Looks like you went with three layers on the L's?

[plcamp]

Making some progress! Your gantry being supported solely by the edges of one sheet of plywood is a gutsy move. Probably be fine, but long term stability might be worth keeping an eye on. Looks like you went with three layers on the L's?

The vertical gantry supports are fabricated from laminated 3/4" birch ply for a thickness of 1-1/2". I'm not really sure about your gantry comment. The gantry is a box section supported front and back by the vertical support, and I believe this is illustrated in one of my earlier pictures. Also please note that the front and rear gantry beams have a vertical extension that will tie into the support for additional lateral stability. The torsional element is an unknown at this time.

[Devastator]

I'm not really sure about your gantry comment.

Where your angle iron is attached where your gantry V bearings ride. Looks like one sheet of plywood. Forgive me if I'm mistaken, photos can be deceiving as far as scale.

[plcamp]

Where your angle iron is attached where your gantry V bearings ride. Looks like one sheet of plywood. Forgive me if I'm mistaken, photos can be deceiving as far as scale.

I have attached a view of the gantry and X-Axis carriage cut thru the bearings to show my design intent. Hope this sheds more light on how the assembly comes together, and yes pictures can sometimes be confusing as it's not always easy to capture all of the detail.

Also note that I have used a 3-rail 6-bearing carriage for the X-axis, 4 mounted to the front of the gantry and 2 mounted to the rear. My intent here is to distribute any of the twisting forces to both the front and back faces of the gantry.

[ger21]

Looking at that drawing, it appears that your spindle clamp attachment to the Z plate is the weak link. I would guess that the spindle will easily flex from front to back unless you add some side plates to the clamp.

[plcamp]

Looking at that drawing, it appears that your spindle clamp attachment to the Z plate is the weak link. I would guess that the spindle will easily flex from front to back unless you add some side plates to the clamp.

Gerry, this is how it comes together

Paul