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Dave,
I had the same problem. I just cut everything to a consistent 23 3/4" and moved on. I can't see that it will be a problem.
Randy
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I was about to start cutting plywood today for the base when I noticed things are not always as they first appear. Turns out my 24"x48" plywood sheets are anywhere from 23 9/16" to 23 15/16" wide. Given that the overall front to back dimension of the base is 24" this is creating a problem.
Being frugal (as some of the others here are) I hate to have to buy 48x96 sheets and then cut them down to size. This dilemma has me wondering if there is another solution to my problem. Specifically will this work if I go to 23 1/2" for my overall dimensions. I have been studying my plans intently for the past hour to see if this will work, considering I have all my metal pieces made and assembled at least as far as you can get without the wood base.
The critical pieces seem to be the x direction plates and rails as they are all 24" long. However I note on page 115 the plates are flush with the back edge of the base but do not line up with anything at the front. In addition the front flange pieces extend beyond the top wood plates. This all makes me think that 23 1/2" front to back should work. Worst case would be the need to cut a half inch off all the plates and rails.
Any ideas on where I may be missing something?
Thanks, Dave
Dave,
I had the same problem. I just cut everything to a consistent 23 3/4" and moved on. I can't see that it will be a problem.
Randy
I wouldnt sweat it too much. i cut all my wood pieces to the dimensions in the plans and ended up with some overhang that I flush trimmed to meet up with the edge of the door and front flange area. Keep in mind that 3/4 ply is typically less then 3/4. On my CNC the floor measures 23 7/8" and the bottom is exactly the same on front to back dimension. For the very bottom piece as long as you are close you should be fine. All this piece does initially is get the X and Y ribs lined up and mounted. The key here is to draw the pencil lines as the plans show except for the lines for the outer edge pices, adjust them to over hang as necessary. With that said, first cut the top and bottom pieces as close as you can to the plans and then layout the ribs and see how everything aligns and adjust from there. One more option, dont make the back door opening and that way you wont need that extra 3/4 lip on the top sheet. I wouldn't buy more ply for that minor of a discrepency. If you are still worried, you can definately go with the 23 1/2" option you mentioned and adjust the other parts accordingly. I cant see it having a huge impact on your build and will only change your work area but 0.5".Originally Posted by kemper45
Good luck!
billj
I don't know what your fabricating tool selection looks like, but I would suggest using the classic woodworking solution of edge banding your plywood with a strip of hardwood. This would increase your sheet width enough for the existing build.
If you change any dimension, you have to chase it through all the parts and find out what actually needs changing.
Mine you, I am going to modify the base, but I'm willing to go through the effort.
The x-plates do line up with something. They line up in the front with the split line between the top plates and the front flange. Not that its noticable once finished and painted. I doubt its critical though 1/2" is a lot.
I do think it would be easier to laminate a hardwood edge on the existing plywood blank than to modify the plans to suit.
Thanks for the replies guys. I think I am going to go the 23 1/2" route and see where it gets me. I am pretty good at reading plans so I should be able to chase the changes throughout the rest of the pieces. I will keep the other suggestions in mind as I work through this. Hoping to getting started this weekend and see if I can at least get the torsion box done.
Cheers, Dave
I just checked measurements on mine again. The 3/4" birch ply is 11/16ths on a micrometer which is standard thickness for all ply. There is really no such think as exact 3/4" ply. The dimensions for the wood base in the plans are all done from CAD using 0.75" as the measurement. As I stated before I cut everything to the exact dimensions in the plan for the base and had to trim 1/8th off the front of the top skin before I could mount the flange pieces and 1/8th of the front edge of the bottom skin. My CNC base from front to back is 23 7/8" and I did not have to make any changes to the rest of the metal pieces. As long as your left-to-right measurements are fairly accurate you will not need to change the dimensions on any of the metal pieces. As Michael said, the X rails do line up with the line that seperates the base and flange pieces but this is not really a critical issue. They can overlap the full distance of the flange and the only thing affected would be the top plastic hood which is more of a safety piece and not needed to operate the machine. Depending on the location of the limit switches for X will determine how far X can travel and if you use the front location shown in the plans then the rails on the Gantry will not even come close to rolling over the flange even if the X axis plates are over that seperation line. You can add hardwood strips if you want to spend the extra time and then have to take them off because you will see the top skin will be too long. Your best bet, cut all your pieces and do a trial build of the bottom skin, top skin, rear plate, front plate and ribs and you will see what you are working with and then determine if you need to fix it. One other thing to consider, if you do have a short piece for the top skin you can either leave the gap in the rear where the door goes or even better in the front where it is supposed to meet the flange and when you do the epoxy coat it will fill in the gap automatically.
Billj
You could always do what I'm doing on my next build and buy 3/4" thick aluminum plate for the top skin, right and left skins, and top pices that the X rails mount to. I plan to integrate the flange and skins together instead of having seperate pieces.
Billj
Dave, you have been preparing to build your base for weeks now, whats the hold up?
Bill,
My excuses in no particular order:
- work (the type that pays the bills)
- honey do list
- getting my table saw set up in the garage
- cleaning the garage to the point that above could be done
- buying the plywood
- watching too much of the NHL playoffs (I am Canadian after all)
- making a zero clearance insert for my table saw (which will be much easier once the CNC is done)
- life in general
OK, no more excuses time to get to it.
Dave
LOL Dave, I hear you but I felt giving you a hard time would help get you moving. My list looks almost the same but replace NHL with kids soccer and we are about the same. Well except for the first 2 items, my wife feels her list of things for me to do should be more important then the thing that pays the bills and the thing that pays the bills is only 50 feet from the garage where all the tools and projects areBill,
My excuses in no particular order:
- work (the type that pays the bills)
- honey do list
- getting my table saw set up in the garage
- cleaning the garage to the point that above could be done
- buying the plywood
- watching too much of the NHL playoffs (I am Canadian after all)
- making a zero clearance insert for my table saw (which will be much easier once the CNC is done)
- life in general
OK, no more excuses time to get to it.
Dave
I would just build it to the 23 1/2" dimension and then increase the front flange by the missing 1/2". The X plates/rails will then extend onto the top of the flange, but that shouldn't effect anything.
Bill- I'm looking forward to seeing that aluminum table.
-Bob
ME TOO! Bob
Here's where I'm at for the next build...
Sub base/ribs/and outer skins in either delrin or carbon fiber at the thickness spec'd in the plans. The only changes will be an extra foot on the X axis and 6 to 8 inches on the Y axis. For the floor/left and right skins/ and top pieces that the x rails mount to will be 3/4" 6061 aluminum. For the X rails I want to get rid of the angle iron pieces and use 1.125 square rod instead, this will increase rigidity. The gantry will be upgraded to handle the increase Y axis dimension. The carriage will be machined out of solid 6061. ABEC 9s (except for the cable arm). 425 oz. in. steppers. External controller box. An actual mill spindle with seperate controller and power supply. Once built, I'm going to program it to drill a grid of holes in the entire table the tap the hols and add T-slot rails. This is overkill for the application it is being built for and I may do it in steps as upgrades rather then all at once. I'm at about $1500 for the build since I can use quite a bit of the original machine hardware and electronics. I have already completed my CAD drawings for the changes and will start ordering material within the next week or two.
Will post pics of prgress soon I hope.
Billj
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