[matth]

Hi All,

Just wanted to start a thread following the design and build of my second aluminium gantry router.
I currently have a 2' x 4' all aluminium router based on THK type rails and ballscrews. This was built just for the building rather than a specific reason.
I have never really found a reason to cut anything bigger than 12" square so this machine is really overkill.

I plan on building (and have started to collect parts for) a smaller much heavier duty router with a decent spindle that will be for wood, plastics and aluminium but be capable of light cuts in mild steel.

The frame and gantry support will be based on some aluminium profile I have got hold of (this is 66mm sq and very heavy duty). the Gantry side support will hopefully be 16mm Aluminium plate and all other parts will be 10mm plate.
The XYZ rails with be fully supported linear shaft 20mm,16mm,12mm respectively.
Screws will all be 16mm 5mm lead ballscrews which I will turn down as required.

I will jopefully have a 20mm T Slot table but we'll see.

Cutting area should be 475mm x 300mm x 150mm

[matth]

I have now added the balscrews into the design (minus the end supports as I haven't rumaged around for bearings yet).
The rails and screws have now been ordered so the only thing I'm short of is the bigger plate sections.

The Y screw is actually inside the top gantry profile section with a slot opened out for the ballnut connection.
Any opinions on the size of this connection (20mmx30mm off the nut with a 30mmx25mm bar running to the back of the Z carriage) and potential racking issues?

[matth]

Just purchased all the aluminium plate for this project (I have managed to get the 16mm for the side panels) so I now have most of the mechnical componants to finalise the design.

My plan for the spindle is to use the headstock from a Emco Unimat lathe, this has an M14 spindle rated upto 4000RPM to which I'd fit an ER25 collet holder. I would mount this up to the Z axis plate along with a 1/4HP motor running off an invertor for speed control.

Do you guys think this would be a good match on a small heavy gantry router like this and what's your opinion on the ability of this setup to make light cuts in steel?

Now I've got to work out how to cut the 16mm side plates on my existing machine with a 24K RPM Router!

[matth]

Mostly everything is ordered for this machine now so hopefully you will see some real pics soon.

I have settled on the Emco Unimat spindle with a 1/8th HP AC motor mounted to the Z plate (I will have a couple of other plates for a trim router and a 3.5HP router as well).
The Emco spindle will be fitted with an ER16 collet holder which I have on order along with a set of ER16 collets.

I have modified the design to take another length of profile in the Y gantry to spread the Y rails apart, this also means that the Y ballscrew can be fitted in the middle profile and will drive the Z carriage from it's centre line.
Because the mating faces of the gantry and side panels is now so large I can afford to reduce the width of the bottom cross brace and now have room for the legs.
The three gantry cross member profiles all bolt together with special clamps that came with the profile and will effectively make the three peices into one very sturdy part.
I still have to design the ballscrew mounts and tweak the design but I'm almost there.

[matth]

A couple of real pictures to prove I'm not just daydreaming!

These are just offcuts but they show the profile system (quick-set) and it's construction.

The first pic is of the gantry cross-section and the second is a mockup of a frame corner and leg:

[PaulD]

Looks stout enough. I'm curious about the source/manufacturer of the aluminum extrusions. I haven't seen that one before. I have seen similar rail/ bearing slides used in machine applications. I like the idea of that type of rail / bearings for the axis slides. Probably have very little rolling resistance. I think I remember that the rails are hardened for longevity. I am in the planning stage.....err wishing stage of a build and am looking around to see what other folks are doing. I have been accused of almost always overbuilding machines, but have rarely experienced any failures.
I will be making regular trips to the local salvage yard. I have seen just about everything imaginable there for building these machines. I may end up with 1" ball screws (I've seen them there before) It may take me a while to find stepper motors small enough for a build. I have seen some at the yard that were in the 1-2 hp size. A bit overkill for a router!! Besides, most of what I've seen there required more power than I have on the farm.

Keep the updates coming, I will be following your build and thanks for posting.

[matth]

Wow, fast shipping from China! Who'd have thought?

6 Days from order to my door for all my screws and rails, very impressed.

I came home from work yesterday and found my aluminium and Tailstock die holder (required to cut the threads on my screws, i'm not up to screw cutting on my 7X12). So now I have almost everything to progress this machine.

Just waiting on my Unimat headstock and collets and holder now and also the drive motor.

I'm going to have a merry cnc'ing christmas break!

[matth]

Hi Paul, thanks for your post.

The profile is marked as "quick-set" and is very heavy duty, I got mine off Ebay for a steal (£15 for about 4Metres and loads of fixings e.g. corners, angle brackets etc). I have done a few searches online to find this profile but with no luck, in my opinion it would make an excellent alternative to 80/20.

Not trying to promote anyone over anyone else but for UK cnc'ers linearmotionbearings2008 on Ebay is an excellent seller and a very cost effective alternative to some other very well known UK sellers.

[matth]

Busy, busy, busy today opening the door to delivery men!

The motor and spindle have just turned up.

The spindle is tiny but very solid and better than anything I could come up with, it is also much better at taking side loads than a wood router.

[matth]

OK, so been a while since I posted on this last and some developments have happen:

I have been doing a lot of thinking about the use of the round rails, these are good units but I really prefer the THK units that are on my existing machine. As I want to be able to make light cuts in steel I have redesigned the machine to make use of the some of the rails from my current router and I have purchased a set of thompson THK style rails as well.
This gives me 25mm rails for X, 20mm rails for Y and 12mm rails for Z.
I have also changed the layout to a wide desktop style as this will sit in position better and makes for a more compact layout.
The design is 99% finished and I have started to machine the ballscrews (very slow going on my 7x12 but I am getting a nice finish).

[matth]

These are the rails I have purchased for the X axis:

[muddobber76]

Thats a nice looking build so far. Looks very stout. Those x-axis rails? Did you happen to get those from ebay store Dock Hardware? I just ordered a set that looks just like those, they are Thompson. Just wondering what you think of them, condition etc. Keep up the good work!!

[matth]

LOL, yes they are from Dock Hardware but I haven't received them yet. I will post pics as soon as I have them.

[Mr.Chips]

OK, so been a while since I posted on this last and some developments have happen:

I have been doing a lot of thinking about the use of the round rails, these are good units but I really prefer the THK units that are on my existing machine. As I want to be able to make light cuts in steel I have redesigned the machine to make use of the some of the rails from my current router and I have purchased a set of thompson THK style rails as well.
This gives me 25mm rails for X, 20mm rails for Y and 12mm rails for Z.
I have also changed the layout to a wide desktop style as this will sit in position better and makes for a more compact layout.
The design is 99% finished and I have started to machine the ballscrews (very slow going on my 7x12 but I am getting a nice finish).

Some heavy duty structures there.

Have you considered moving the X stepper to the other end of the machine, that way the cutter head might be able to peek over the end and you could mount something verticaly for cutting on the end. I see people even mounting a small 4th axis there for making a lathe of sorts and even clamping wood there and cutting some precision dovetails.
Good luck and keep the pictures coming.

[matth]

The X drive is there so that I can put the back of the router against a wall or back of an enclosure. The top that I plan to mount will extend beyond the frame as per pic and enable me to use the entire envelope.
The table surface is going to be made up of a first layer of 8mm thick CRS lengths tacked together with a 10mm solid Aluminium plate sat ontop (I may if funds permit then add a 20mm Aluminium plate that is the size of the cutting area which will then be skim cut and possibly T-Slots added.

[matth]

Just to let everyone know that this project is still progressing.
Been taking a while to order all the materials and polish off the design.
I have also had to strip and rebuild my mill and add the shumatech DRO which has been lying around for ages.
This weekend I cut the journels on the Z axis ballscrew to test my new lathe tooling (live centre, collet chuck) and also made up a new Z axis tool plate for my existing Gantry router, it was fitted with a 2 1/2 HP Dewalt fixed base router with a set speed of 24K RPM (just to fast to cut thick aluminium plate). I have now machined and fitted a new plate with the Unimat Headstock and AC motor onboard (using a couple of small timing pulleys I had lying around). The headstock is fitted with a ER16 chuck and runs at 2800 RPM so should enable me to cut the plates (16mm and 20mm).

I will post some pics soon.

I also got my hands on a 20mm Aluminium plate for the table of the machine, I was thinking of milling small T-Slots on my existing Gantry (10mm deep with the T being 5mm deep and 5mm wide each side).
How feasible do you think this is on my existing setup with a small woodruff cutter?
The other option is to drill and tap a matrix of holes for bolt down but my worry is suds collection as I will be adding flood cooling to this machine.

[matth]

A couple of pics of the Z axis ballscrew after turning down the ends for the bearings.
Please ignore the rough end, I tried to use an M12 course Die and the scouring is on the 10mm motor end (you can see where the die got to the 12mm part and stalled), I have now ordered a 12mm fine die which should cut fine and clear the motor connection end. I will skim the end of this ballscrew down to clean it as the diamesion is not critical.

You can see in the pics that the screw has turned nicely (this was done on a 7x12 with brazed carbide tooling after using a cutoff wheel in an angle grinder to rough down the diamieter), I used a high RPM (2000) and an agressive feed rate and depth of cut (0.004") which gave a nice finish and lots of smoke and glowing swarf!
It's worth noting that these are C7 ground screws and the hardening runs down at least 3mm (so I didn't cut through on the journals).

So proof that you can turn hardened screws on a cheap 7x12!

[matth]

Also a couple of pics of the dockhardware rails for the interested, these are very big and heavy duty and should do the job well.

[matth]

Lastly a couple of pics showing the new temp Z axis setup on my existing router to enable me to cut the aluminium plates.
The moter is a 1/4 HP AC unit running the Unimat headstock, I have a 650W DC motor for the final machine which will have a lot more power and I will hook it up to Mach 3 for spindle control.

[matth]

Another render of the finalised design: