It is hard to tell from your pictures and since the y, z and spindle aren't yet mounted, but will your spindle be in the center of your X travel?
It looks like (if you needed to) you could move your whole bridge forward slightly. Is that possible?
The construction of this machine looks extremely solid. What are you going to do for your gantry rail? Are you going to extend it past the aluminum on the gantry? My only concern would be that you might have limited travel in this axis. I think everything will be incredibly stiff on this -- I have seen far spindlier moving gantry machines that have made acceptable cuts, so I would personally try to maximize your travel on the gantry.
festool fan eh?
I appreciate all the comments.
I think that the spindle will be close to the center of my base. Unfortunately, it will be difficult to move the gantry. If necessary, I think that I'll be able to move the X axis rails a little more than an inch.
I plan to use spacer so that the Y axis can move almost the full length of the gantry.
A little more progress today. Made and attached small 8020 cuttings to extend the width of gantry. Prepared and attached the 1/4" steel plate to the gantry.
Painted the steel on the gantry and the steel support for the X rails. Mounted the completed Z axis onto the Y axis. The stepper motor has not been connected. The photos below show the potential travel on the Y axis. The third photo shows the spacer I inserted to increase the Y travel. The X axis rails are not currently attached.
It doesn't show well in this photograph but the Z axis does not have a whole lot of usable travel unless I greatly extend the plate that I purchased from CNCRouterParts.com. A much better solution would be to have the two sets of bearing blocks mounted back-to-back on a single plate. That way the set up would be much more rigid and have much more usable travel without cantilevering the cutter way below the bearings. CNCRouterParts.com just started selling a mounting plate to just that. (http://www.cncrouterparts.com/produc...roducts_id=101) I think I will make a plate that incorporates the spacers that I need to maximize Y axis travel.
Last edited by DonFrambach; 10-25-2010 at 11:38 AM. Reason: added link to part from CNCRouterParts.com
Looking real nice, please keep the pics coming.
Thanks for sharing,
Last edited by DeadTom; 10-25-2010 at 10:35 AM. Reason: Came to the party too late
Hi, nice stiff build - I am a big fan of fixed gantry setups.
I used 2 sets of bearing trucks to get the extended length stiffness, but on a 4x8 router.
You can go much longer with that plate and still be ok. cncrouterparts also makes a single longer truck.
Z axis travel is important for work - don't cut yourself short on it.
That's looking very respectable so far Don. Had you considered turning that Z plate upside down, so its side bearings are lower and closer to the tool (ie less deflection). Of course that depends on the length fo the spindle and tool.
On my machine I used a drilled plate with 10mm grid, so I can easily lift or lower the spindle by screwing it on at a different height, then set the max Z travel at 60mm. The result is that there is very little deflection distance when using short tools (as you do for heavy cutting) but if using long tools etc I can just re-mount the spindle higher up and still keep the bearings low and close to the cut for max rigidity. Hope that makes sense.
Made the plate to allow the carriages to be mounted back to back. The first two photos show different views of the plate.
Mounted the plate using extended carriages available form CNCRouterParts.com. This reduced the Y travel from a theoretical 16 to a potential 14 inches. The potential travel is shown in the next two photos.
I then mounted the Z axis to the plate again using extended carriages. This severely reduced my Z travel to a little less than 2 inches. I'm going to get another steel plate to increase the Z travel but I haven't figured out how much I'll need.
Oops!, booboo shown in the last picture. I forgot to account for the height of the screw heads holding the Z carriages in place. I'll need to make a small relief in the plate for the two middle screws. darn!
Last edited by DonFrambach; 11-02-2010 at 12:45 AM. Reason: corrected z travel from less than 3 to less than 2 inches