New member with a new 8020 design

I am working on a 8020 bolt together design. I have been working on this for a couple of months. It has really come a long way. I would like to share a PDF with you for input as it is different that anything I have seen.It will be using CRS rails and CNCrouterparts trucks. I have designed it so that it can be converted from a roller chain to lead screw or rack and pinion. the lead screw design and rack and pinion are from CNC routerparts also. I have designed it with two removable tables should you want to index a full sheet of plywood through it. most people use only a few feet of work space for most of their projects. The x axis is above the cutting table removing the problem of wood chips getehering on the rails and it also reduces the moment to the cutter head. It has been designed around the Porter Cable 7518 router.

Hi cncgreg,

Welcome to the forum! Interesting post, need a bit of time to visualise all the aspects of this design. Do you have any isometric dwgs (i.e. from an angle).

Couple of comments:
The y axis looks like it has an unsupported overhang, is this part of the requirements?
The cutting table also has an overhang, with a bracing piece. Can this support be improved?
Can the supports basically all be moved out to support at the ends?
Are those bracing wire cables or solid thin bars?
The gantry looks a bit small in section compared to the large offset down to the cutting area. You might want to upgrade this part. In fact the more I look at that aspect, the more I think it might be the limiting factor in this machine.

Looks a bit like Florin's design (search for his recent build posts), although compacted down in one axis. Maybe have a look at his design before cutting any bits out?

Good stuff anyway and wish you well with it . . .

Welcome,,,

Interesting use of tensioning cables ( i guess thats what they are), how do you plan to tension them and balance the structure?

Looks okay. Suggest you reduce all the overhangs as much as possible. The gantry arm could come down a bit. Replace the tension wires with single diagonals of angle iron, it will save you hours of setting up and it will stay set :beer:

Robin

Thanks for the replies. I run a cnc plasma touch as a hobbie so the plates i cut myself. you might look for a plasma maching in your area they can be cut much cheaper that the aluminum

Quote:

---

Originally Posted by Robin Hewitt

Looks okay. Suggest you reduce all the overhangs as much as possible. The gantry arm could come down a bit. Replace the tension wires with single diagonals of angle iron, it will save you hours of setting up and it will stay set :beer:

Robin

---

I am sorry what looks like tension wires is really a 1" X 1/8" steel strap the single line on the drawing is really the center to center distance.

Quote:

---

Originally Posted by routercnc

Hi cncgreg,

Welcome to the forum! Interesting post, need a bit of time to visualise all the aspects of this design. Do you have any isometric dwgs (i.e. from an angle).

Couple of comments:
The y axis looks like it has an unsupported overhang, is this part of the requirements?
The cutting table also has an overhang, with a bracing piece. Can this support be improved?
Can the supports basically all be moved out to support at the ends?
Are those bracing wire cables or solid thin bars?
The gantry looks a bit small in section compared to the large offset down to the cutting area. You might want to upgrade this part. In fact the more I look at that aspect, the more I think it might be the limiting factor in this machine.

Looks a bit like Florin's design (search for his recent build posts), although compacted down in one axis. Maybe have a look at his design before cutting any bits out?

Good stuff anyway and wish you well with it . . .

---

the x and y asiz are swaped teh y is actuall the longer axis. the cantilever was design in to allow access to the cutting head for bit changes etc. teh reason is that with teh x axiis over the work area it limits the access to the router motor itself. with a short cantilever some of that acess can be recovered. no one has commented about indexing a full sheet of ply using the removable out tables?

Greg - merged your two threads into one...

Please open a new build thread here when you start

thanks I will

Hi Greg,

Ah, that clarifies a few things. So taking the dwgs as top, middle, and bottom, you will be standing facing the middle dwg when it is operating, with the support tables off to your far left, and far right.

Sounds like you have thought through what you want to do. Still, looking at the gantry section size vs the drop down to the cutting area I'm a bit concerned. Wood might just make it if you are gentle, but hardwood or a bit of ali might chatter and resonate. Do you need all this clearance? How about removable bolt in sections to raise and lower the gantry sides for different jobs? Or, maybe an extra gantry section a short distance above the current to give you more support. You need a bit more stiffness than the plasma you are using currently when routing.

OK, the out tables are fine as far as I can tell, and a method used widely in wood working anyway. Your only issue as such will be when you want to do a bit of cnc in one area, which needs to be continued, or be at a specific distance away from another section. If you are only cutting out small bits, and using it as a means to use up big sheets then I see no problem myself. Or, am I being silly and you intend to motorise the indexing with a stepper some how?

Anyway, if this is your first router based m/c, you will probably build it prod it and poke it, and find that some part of it could be better, then be forever tweaking!

Thanks for the comments. With the plasma cnc I currentlly operate I can continue a cut longer than the table by indexing the sheet through the machine. the sheet is cut the size of the table and then indexed through the table to a known point to continue the other half of the sheet.

OK Greg, got it now.

Well, I obviously can't tempt you with a gantry upgrade, so good luck and look forward to the build . . .