I’m replacing my y-axis plates with thicker versions and need longer screws to secure the plates to the Makerslide. My machine came with the thread forming screws, so I’m wondering if I need to buy a longer version of the same type or if I can buy the standard (non-thread forming) type that currently ship with the machine.
Will an M5 screw work regardless?
I appreciate you test fitting the screws. I’ll go ahead and order a longer M5-0.8 like you suggested. My plates are 3/8" aluminum, so it looks like the 20mm length is the closest standard fit.
Thanks for the help!
FYI - you can tap them to M6 as well. I used longer, M6 screws after re-tapping my Makerslide. So, if you strip one, all is not lost. Of course, you would need an M6 tap.
Thanks, I just finished milling them today on the Xcarve. The finish turned out okay, but plenty good enough for the application. I’ll look into improving the surface finish if I ever need a more precise metal part made.
I would have gone with steel as you did if I had the machinery. Although, if I had the equipment to make steel plates then I probably wouldn’t be using my Xcarve.
I think yours look great. What kind of finish do you have on them?
Ah, now the gantry end plates I’ve been looking at now for a while as a source of my X-shudder… I’ll be really interested in seeing how yours come out!
I’ve been considering making mine heavier, just to see if that dampens the vibration.
I ended up having some time between classes today to head to the machine shop and surface the plates. The largest endmill I could find was a 1.5", so there is some overlap in the surface finish, but I think it came out great.
Looks darn good, man!
Thanks! I’ll do an update when I have everything installed with some results related to any changes in stiffness/rigidity in machining. Hopefully it helps a bit, but I’m not sure how it’ll turn out.
I installed the new y-axis plates today. I’ve noticed a large increase in stiffness in the y-direction. I think this is partly do to the thickness of the new plates (0.375") and also because the bottom of the plates have a larger surface area to mount to with the addition of the aluminum bed.
I’m happy with the increase in height. Now I can slide longer pieces underneath the path of the y-axis travel, along with increasing material height underneath the spindle. This last part is especially important to me when I have the fixed dustboot hooked up. The z-travel was fairly limited with the dustboot before upgrading to the larger plates.
I like it! Man, that looks a LOT stiffer.
It’s beautiful, but I think physics might be your enemy here. Anyone?
What part is the enemy?
The anchor point at the base. You have increased the lever arm by making the bracket higher. If the bracket had more surface area in contact with the base (a thicker base) the rigidity of a thicker plate would pay off. Right now, there is likely a trade off of instability created by a longer lever arm attached to an already weak (by comparison) base. Increases in height will have a logarithmic impact on instability when you have a weak connection at the base. This is easily remedied by making a solid base equal to the combined height of your base extrusion and whatever that his beneath the extrustions. Say, a double thickness of MDF surrounded by and securely attached to a double height outer perimeter of extrusion. OR - getting rid of the extrusion altogether and creating a rigid, thicker base out of some material and lowering your new brackets so they have twice as much surface area contact with the solid base.
To test this, remove your makerslide from one of these brackets and use the tip of your finger at the very top of your bracket to try to push it in. Compare that force to the amount of force required to move your original brackets the same distance. And you will see the impact the increased height has on stability. To keep your new bracket in its appropriate plane, it needs exponentially more support from the base.
Does that make sense? You have a beast here but it is balancing on its on tippy toes.
You bring up a good point. I’ve been thinking about possible issues with that and was worried it may cause problems. My backup plan is to drill two holes at the base of each plate, above the existing bottom holes, and attach two more fasteners to secure the plates to the aluminum bed.
So far, so good! It definitely feels more rigid than it looks, but I know when I first saw it I expected it to be a bit wobbly.
I think you could just tie your two plates on each side together. At 3/8" thick, you could probably drill and tap two holes in the edge of each bracket and run an aluminum or steel brace on the outsides of those brackets. This could serve as a dust shield as well. Then they are tied together at the top and at the bottom. You could probably get away with acrylic as well which might look cool. The taller the better. That way you don’t have to modify your base or dissassemble your machine in any way (but drilling those edges might be easier on a press). Try a 5mm tap - you probably have one of those already.
Are you referring to running a brace in the x-directions or the y-directions? I’m not sure if you mean the plates are unstable front to back or side to side.
Front to back. I am sure it is very stable side to side. I believe on most machines this would be your Y direction.
That’s a great way to deal with the issue. I’m sure you notice a lot of improvement on the larger machine.
I was curious about what you mentioned for the aluminum plates being less stable, so I ran some numbers to get a good idea of the differences. It turns out that the lever arm for the standard steel plate multiplies the force of the y-axis by ~6.2, whereas the aluminum plate multiplies it by ~3.7. This means the fasteners securing the plates to the aluminum extrusion will see less stress with the larger plates. Then, taking into account the properties of the steel and aluminum, along with their dimensions, any deflection of the steel is 5.6 times greater than that of the aluminum plates.
So it turns out that because of the thickness of the aluminum plates, and also with the additional support of the aluminum bed, the taller plates will see anywhere between 1.6 and 5.6 times less deflection than the steel plates. There are some other factors I didn’t include in modeling the problem, but I believe they don’t contribute enough to bother including.
