Well I have finally started to build my router. The plan is for it to cut wood and aluminium. Here is a parts run down for the different axis:

X axis:
6 x 300mm 12mm THK rails with 6 x carridges
2 x 400 Oz/in Nema 34 steppers
1 x 800mm 25mm balscrew with two nuts

Y axis:
2 x 520mm 12mm THK rails with 4 x carridges
1 x 380 Oz/in Nema 34 stepper
1 x 350mm 25mm ballscrew with 2 x nuts

Z axis:
2 x 200mm 9mm THK rails with 4 x carridges
1 x 250 Oz/in Nema stepper
1 x 150mm 16mm Ballscrew with 1 x nut

The main frame work wil be completed using 44mm aluminium box section 3.2mm wall thickness.

Here is the work that has been done on the y & z axis:

I wouldn't have used the 12mm parts, but I'm intersted in seeing what your experience is. Looks like you've done some nice work.

I hear you on the 12mm, unfortunitly rails are hard to come by for a good price in the UK so its use what you can. Its because of the 12mm rails that the Y axis is using one rails on top and one below (trying to spread the load into the structure as much as possible). The Z is using 9mm rails! But these seem to be holding up very well without any noticable deflection.

It shouldn't be a big problem with the 9's and 12's as long as you're not going to cut harder stuff. The rails are holding for very high loads even though they are small, somehwere between 2 and 4 kN per wagon. Make sure to mount them as far as possible and it would work.
And hey, if they would break - then fix it! :)

--Sven

Well, progress stalled for a little while as I am waiting on some aluminium sheet and box section.
Whilst I have been waiting I started to reconsider the usage requirements for this machine. I have decided that the working envelope is just to small for what I'd like to acheive (cutting acrylic for custom marine fish tank sumps, aluminium for 1/6 scale rc car parts and general wood work). 4' x 2' would allow me to cut 1/4 sections of full size standard sheets.
To this end I have purchased some more parts for the x axis and will use the parts from the old plan to increase the size of the y axis. The z axis carridge will remain the same but I have also sourced a very heavy duty 270mm rail that I may use to redesign the slide assembly (this rail is 42mm wide!!).
So whilst I'm waiting on the main parts shown below to arrive from Germany I will work on the y axis (as soon as my aluminium turns up).
I'll keep you updated!

I have now purchased the last componant needed for the revised layout. Once all my parts arrive I will start the assembly in earnest.

Still waiting on my parts for the X axis but I have now started on the longer Y and revised Z.
The Y is using the same arrangement as before but is using the longer rails from the old X axis design, it is also using a "mount and play" ballscrew assembly form jimonchan on Ebay (excellent product, price and service).
The new Z is using a single heavy duty (43mm) IKO rail instead of the previous 2 9mm THK rails. I'm hoping that it should be stronger with less flex than the old design even though its only using one carridge. Nest steps are to make up the back plate of the Y axis and the ballnut attachement plate and then build the Y motor mount. Stay tuned!

More happening, slowly but surely.
The Z axis motor mount has now been made and tomorow I will hopefully finish the Z all together. To connect to the box section I have made a small aluminium block to slot into the end of the box section and allow everything to be bolted together.

looking real nice. keep the updates coming.

on your z, it doesnt look like you have any thrust bearings and have the motor coupled directly to the ballscrew. this may work for a little while but the bearings in the motor are not meant to take thrust loads.

Very good point Jimbo, I had not considered that!
I will add a L plate to the bottom of the screw and bore a recess for a skate bearing (I know their not for thrust loads but it can be replaced easily).
I'll post some pics of this tomorrow.

Question:

I'm currently considering my last purchase which is the material for the X axis supports. The sides of the machine will be roughly 2 metres longwith a support at each end, the 1.8 metre rails will be bolted to the sides. I have a bunch of 2" x 2" X 10G and 1" x 4" x 10G box section so I'd like to use something that will match up with this well.

The options are:

1" x 4" X 10G box section (mounted vertically)
1/2" x 4" solid bar
2" x 2" solid Bar

The cheapest and simplest option is the box section, any opinions out there on the suitibility of these materials??

Right, time to get back on this horse!

I finally decided on 6" x 2" aluminium RHS for my main rails.
Now that I have the materials I thought it best to put together a model.
Watch this space for updates!

Right, finally some movement on this project. The YZ axis have now been bolted together to form the gantry (I wanted to build the gantry first so I could dimension the frame properly). The box section is bolted together using solid aluminium blocks in the ends. All that is left to do on the gantry is to make the router plate and build the x axis nut carrier.
I am currently working on sizing the peices of the frame, the 4 main sides are 6" x 2" and the table supports are 1.75" x 1.75".
The pic with the rails attached shows the rough side of the finished router.

is that a one turn per inch leadscrew?

Leadscrew is 20mm per turn.

Almost finished the frame, working on all the pieces at the moment so it should all come together really fast!
Here are some pics to show how I am joining the box section together. You can also see the x axis ballscrew bearing carrier installed through the crossmember.

Working on the main x axis support members tonight so hopefully should see it all bolted together tomorrow. Here are some pictures of the cross members and ballscrew mocked up. For some sense of scale just remember that the x rails are nearly 2 metres long:

What do you plan to use for the table?

Oringinally I was thinking along the lines of a sheet of 1" marine ply, but now the machine is coming along I am considering a quarter sheet of 10mm aluminium (i'll see how the money goes!).

Here are yet more pics of how it is all coming together. Tonight I have drilled the main rails and bolted in the main crossmembers, the gantry is just sat there to give me an idea of the finished look. The main rails are actually bolted on around the wrong way, the larger overhang should be at the end that the motor will bolt to, I will correct this when I drill the rails for the smaller cross members.

I have been thinking alot about what to make the table out of on the machine I want to make. A lot of people use MDF for their tables. I wouldn't think about going with 25mm aluminum if I were going to cut a lot of aluminum.

One of my thoughts about going with MDF is that you can skim cut it with the machine so it is flat with the head. Another advantage is that if you cut into it by mistake you will not feel as bad as on a expensive aluminum table. My local home center has MDF already cut to 2' X 4'. That makes it easy.

One of the things I am wondering is how to size the stepper motors for the machine. I see you are going with 400 in oz motors. I am going to cut mostly plastic and still have to figure what size to use and what control to use. Thinking of using the gecko Drives.

The side plates on your gantry look a little thin to me. I would be worried about flexing when cutting. I would think 25mm or better would be a good thickness. I am thinking of using some 5" X 2 1/4" for the up rights on the gantry.

All in all your machine looks really cool! Close to just what I want to make.

I would forget about using 25mm for the side plates, mine are 12mm and are extremely solid. The entire gantry is only bolted together with 8 M8 bolts and there is no deflection (I can put my foot on the top corner of the gantry and push with all my weight and there is no detectable deflection). 25mm would be very very heavy.
My thoughts against MDF are that it can distort when bolted down and any moisture would cause problems, it would also not add any rigidaty to the frame. If I used a aluminium plate I would skim this, maybe a couple of 5thou passes. The problem with this is that my table will be bigger than my cutting area so skimming will result in a recess.

Sizing steppers is hard as it depends on what screws you use and the speeds you want to run at. My opinion is the bigger the better.

Thanks for the comments, hopefully I will be cutting in the next couple weeks.

Sounds good on the 12mm plates.

Interesting thoughts on MDF. Makes me wonder if it would distort a little every month or so. I am a toolmaker by trade and I can see me not being happy with the table changing every time I go to use the machine. One thing I am thinking of using is a surface plate made of granite. A place in the USA has them cheap. http://www.grizzly.com/products/G9657 To far to ship to you but may interest other in the US. I am told it can be drilled with a hammer drill and threaded inserts installed for hold downs. Problem is that it is about 400lbs. for a 2' X 3' plate. Also I think drilling all those holes in granite would be a lot of work.

Keep up the good work and updates. I'll be watching for your idea's and your first run.

Bret

Matt
If you use a flycutter to skim your table top you can adjust it to reach the edge. You will need a slow spindle though.

Excellent thought on the flycutter!

I think granite would be a bit expensive in the uK plus I really need to be able to move this machine from time to time and a 4' x 2' slab of granite would require a crane!

Again more progress, something must be wrong with me!

As far as the main construction is concerned the only thing left is the feet (I do not have any suitable material at the moment).
The Z axis support also needs the bottom chopped of and the rail moved up to allow for the clearance over the table surface.
Now for the router plate and the connection between the gantry and the x axis nut carrier.

Well finally some more progess on this project.
After extending the shed to accomodate the router I have started to finish it!
I have made up the X axis nut mounting plate and the router plate. All the major metal work is now done, just some limit switch mounting etc to do.
Now on to the driver electronics and software.

Nice looking machine matth! What's the thickness on the gantry side? Maby you should put something along the gantry side to prevent flexing.

Hi GNU,

Thanks, the gantry sides are 10mm Alu (this feels very solid) bolted into 4" box section (the ends of which are very square and act as a very strong brace).
Pushing against the side of the gantry with my body I can detect no flex or deflection.

Good, now I can sleep :)
Planning to use 15mm on a similar design.

Great looking machine Matth. Saltwater aquariums has brought me here also. I'm building a large needlewheel skimmer and decided to build a router to build all the parts for it.

Your router comes together nicely.
I would go for mdf table top, flex is almost nihil,
but I would have it painted because of the moisture when your adding fluid during cutting.

Really nice router and please keep posting.

I too am going to do my machine in aluminium - did you do all the work yourself - if you are close to wakefield i would love to come see the machine

where did you get the aluminium box section from in the UK

All the metal came from http://www.wr-richards.co.uk/
The site is down at the mo but keep an eye on it. A chap called Mark runs the business and is very helpfull (shipping is cheap aswell).

Nice Matth ! I'm reeeaaalllly slowly making a router kinda simular size.. 5 plus years on family life keeps intruding !! I'm from Dorset - Hi

where did you get the aluminium box section from in the UK

I've had some good pickings from the scrap yard - one in Poole had some very useful fairly heavy gauge stuff - another screappy didn't have any tho so check first!

Pat

Keep on it Pat, you'll be impressed with all your effort when you see it zooming around for the first time.
Mine took about 3 years, 2 on research and about 12 months of on and off building.
I find the size very helpfull as I can buy full 8' x 4' sheets of stock and get the supplier to rip them down to quater sheets.

Anyone up north want to share any experiences on aluminium build.I am about to start - The only thing I have so far is the bearings.But have found a local company that should be able to supply the aluminium.