well I have got off my a$$ and

[truman]

well I feel I am at a stage where I will make steady progress so I thought I would start sharing some pictures. Maby get some advice along the way.

[Switcher]

What board is that in the enclosure (to run the motors)?

[truman]

it is an arcsin board from www.buildyouridea.com Dave is a really nice guy. He has been taking a break for a while but he just told me he was going to do another pcb run and sell a kit for the board. There are a couple of features that caught my attention 1. it has a buit on interface for a joystick 2. it is capable of running a second stepper on the x axis. I did build the 3977 drives from Phils site but I wanted something that could take a little more voltage. here is a pic of what I was going to use I think I will use them for a small desktop mill one day.

[truman]

ok here is some more progress on the gantry I have to wait until monday or tuesday for my T nuts to mount the bearings so I think I will test fit the gantry then. this is only a temporary gantry so I can use the router to cut my alluminum hopefully this one will be sturdy enough to cut alluminum. I am learning very quickly that a mill would save you alot of time and headache or even a friend with a mill would be nice LOL!

[truman]

OK here is some more progress unfortunately I still don't think this will be rigid enough to cut aluminum any suggestions to stiffen it up any help would be much appreciated.

[HayTay]

Originally Posted by truman OK here is some more progress unfortunately I still don't think this will be rigid enough to cut aluminum any suggestions to stiffen it up any help would be much appreciated.

You could use aluminum or steel angle to stiffen up all of the corners on the gantry. The outside corners for sure, and maybe the inside ones, too.

It looks like you should remake the sides of your gantry to make them longer on the underside of your table frame. You could then add front and back plates made from wood or metal to stiffen the assembly up even more. A torsion box assembly would probably make it even stiffer than just the front and back support pieces.

See Joe's CNC Model 2006 gantry for inspiration:
http://www.cnczone.com/forums/showpo...0&postcount=42

If you're going to remake the gantry, now's the time. I hope the suggestions give you the help you were looking for.

[truman]

This is only a sacrificial gantry but the idea of angle might be what I was looking for. actually the gantry I made is based on Joes second machine I have been following Joes stuff for a while now he is the one who cut my router mounts for me. what I was hoping to do is cut my aluminum gantry with this one.

thank you

Rob

[truman]

OK I have stiffened the gantry up with 1" square tubing but I have found out that it is the bottom plate that is the weakest link. If I hold both gantry sides and move them in opposite directions I get what I think is called gantry rack. Anyone have ideas how to improve this? any help would be greatly appreciated.

thank you
Rob

[randyf1965]

Without rebuilding everything... I would get a large piece of angle (red part)and fasten it on the gantry sides and bottom on each end of the gantry.

Or you could try the flat metal 90 degree corners (Yellow part)and put the on the front and back ends of the gantry and attach to the gantry bottom front and back edge.

Both probably wouldn't be a bad idea either

[HayTay]

Originally Posted by truman OK I have stiffened the gantry up with 1" square tubing but I have found out that it is the bottom plate that is the weakest link. If I hold both gantry sides and move them in opposite directions I get what I think is called gantry rack. Anyone have ideas how to improve this? any help would be greatly appreciated. thank you Rob

Again...

Originally Posted by HayTay You could use aluminum or steel angle to stiffen up all of the corners on the gantry. The outside corners for sure, and maybe the inside ones, too. It looks like you should remake the sides of your gantry to make them longer on the underside of your table frame. You could then add front and back plates made from wood or metal to stiffen the assembly up even more. A torsion box assembly would probably make it even stiffer than just the front and back support pieces. See Joe's CNC Model 2006 gantry for inspiration: http://www.cnczone.com/forums/showpo...0&postcount=42 If you're going to remake the gantry, now's the time. I hope the suggestions give you the help you were looking for.

[truman]

I know you allready said that haytay and stupid me assumed that the bottom plate wouldn't be the problem I guess I should listen to people who have built machines anyhow the idea for the flat corner brackets was also very good I think i will use both angle and the corner brackets should I double the thickness of the bottom plate as well?

thank you
Rob

[Madclicker]

I don't think you can do much to help the torsional strength of slab MDF by adding pieces of metal. That's why people build torsion boxes. Your problem is the lack of torsional strength. Laminating the slabs of MDF will help a lot, as will doubling the the thickness of the slabs.