Final Design Review

[BrandonBe]

I have purchased the metal and linear motion materials so I am kind of limited with any modifications I can make now.

For the Z-axis, I am making it out of 0.5" steel plate and there is less than a 6" section of the plate that is past the fulcrum (the bottom bearing block). I am having difficulty seeing how this will flex. I am only using this machine for aluminum and woods and I will not be running it very hard most likely.

For the spacer tubes. They are 1/4" steel. I have seen other CNC's like Wade'O's where they machined the tube surface (for the gantry in his case). The tubes are quite small on my CNC so will they have a significant risk of warping? I don't have any experience milling steel tube but I find it hard to picture these tubes warping much.

I'm not fully sure what you mean with the Z axis spacers but I wanted to avoid them but couldn't due to motor clearance as the plate would have impacted the motor. The nut was also at a height that the bearing blocks needed spacers or it would have collided with the Z plate.

The way I am imagining milling the X-axis plates flat is by assembling the base of the frame completely and then putting everything firmly on a mill and milling the surfaces flat with a fly cutter or something. Ideally milling the plates in one go (depending on the clearance the shop's mill has). I am trying to get 0.5" plates instead of the 0.25" ones on my last model.

For the base plate (X-axis plate) : I can't afford a $300-$400 aluminum plate (I may replace it in the future with a decent aluminum one). I live in Canada so shipping and our currency is not making if simple to find affordable aluminum plates. I am going to try to use a hot rolled steel plate (20" x 24" x 0.5") and use a fly cutter on a mill to flatten the surfaces. I will probably finish the surfaces by hand after fly cutting them.

Since I am machining the surface of the x-axis rail mounts once the base if fully assembled, will I still risk having the rails bind? I plan to bolt all the plates together and use thread lock to prevent them from coming loose.

And could you send me a picture of roll pins being used? I have never seen them before and still don't know what exactly they are.

I appreciate all the help again. I am going to have to keep the gantry as is due to the fact that a single upright would not allow the X-axis table to move very far as the upright would be right in the way (unless i'm picturing it wrong).

[louieatienza]

I have purchased the metal and linear motion materials so I am kind of limited with any modifications I can make now.

For the Z-axis, I am making it out of 0.5" steel plate and there is less than a 6" section of the plate that is past the fulcrum (the bottom bearing block). I am having difficulty seeing how this will flex. I am only using this machine for aluminum and woods and I will not be running it very hard most likely.

For the spacer tubes. They are 1/4" steel. I have seen other CNC's like Wade'O's where they machined the tube surface (for the gantry in his case). The tubes are quite small on my CNC so will they have a significant risk of warping? I don't have any experience milling steel tube but I find it hard to picture these tubes warping much.

I'm not fully sure what you mean with the Z axis spacers but I wanted to avoid them but couldn't due to motor clearance as the plate would have impacted the motor. The nut was also at a height that the bearing blocks needed spacers or it would have collided with the Z plate.

The way I am imagining milling the X-axis plates flat is by assembling the base of the frame completely and then putting everything firmly on a mill and milling the surfaces flat with a fly cutter or something. Ideally milling the plates in one go (depending on the clearance the shop's mill has). I am trying to get 0.5" plates instead of the 0.25" ones on my last model.

For the base plate (X-axis plate) : I can't afford a $300-$400 aluminum plate (I may replace it in the future with a decent aluminum one). I live in Canada so shipping and our currency is not making if simple to find affordable aluminum plates. I am going to try to use a hot rolled steel plate (20" x 24" x 0.5") and use a fly cutter on a mill to flatten the surfaces. I will probably finish the surfaces by hand after fly cutting them.

Since I am machining the surface of the x-axis rail mounts once the base if fully assembled, will I still risk having the rails bind? I plan to bolt all the plates together and use thread lock to prevent them from coming loose.

And could you send me a picture of roll pins being used? I have never seen them before and still don't know what exactly they are.

I appreciate all the help again. I am going to have to keep the gantry as is due to the fact that a single upright would not allow the X-axis table to move very far as the upright would be right in the way (unless i'm picturing it wrong).

If you're just cutting aluminum and wood, try sourcing 3/4" to 1-1/4" phenolic sheet. They use them as countertop material, both residential and industrial, and blems and off-cuts are sold very cheaply. Solid stuff, easily milled, and because it is a dissimilar material can help dissipate vibrations.

[dmalicky]

Thanks, Louie, I hadn't thought of phenolic. Do you know what kind is usually used as countertop material and available for low $? (I'm only familiar with the black type used in chemistry labs, but I recall that's expensive and hard to machine.)
I found this, not a bad price: Phenolic Grade XX Sheeting | U.S. Plastic Corp.

[louieatienza]

Thanks, Louie, I hadn't thought of phenolic. Do you know what kind is usually used as countertop material and available for low $? (I'm only familiar with the black type used in chemistry labs, but I recall that's expensive and hard to machine.)
I found this, not a bad price: Phenolic Grade XX Sheeting | U.S. Plastic Corp.

Look up PaperStone, Pionite, Arborist... they also use this stuff for bathroom partitions with a melamine outer surface. If you search PaperStone, you'll find a distributor that sells drop offs and blems. My favorite jig and fixture material.

This stuff is pretty easy to machine, you use regular woodworking bits. Make sure you're using paper based stuff. Cotton based is stronger but the edges don't come out as smooth. Fiberglass based (like G10) are downright brutal, and I use PCD endmills to cut that.

[dmalicky]

Thanks, Louie -- I found some distributors, will check them out.

[rusel]

Great build with lot of good improvements butI can not see how you are going to tram the spindle in the Y direction ( front to back) Or did I miss that....

[samsagaz]

Thanks David!

I added 1" by 2" 3/16" steel tubes as spacers for the X axis and Z axis. I was avoiding these because i wasn't sure if they were strait enough. Will I need to mill the surface of these tubes or will they be flat enough?

I'm going to use hot rolled steel for the gantry, X, Y, Z axis plates, and the mounting plates for the rails on the X axis. I'm planning on milling the surfaces for the rails on the gantry plate, X axis (is 1/4" hot rolled steel thick enough to have the surface milled?), and the z axis plate.

Will I need to mill the plates where I mount the 1" x 2" spacer block tubes to as well?

And I'm still a bit confused about the pins for alignment. Like where exactly will I need to insert the pins?

On question on this design, will not improve anything if the rails are set at botton of the table instead in the tubing? can be replaced the tubing that are using to add support to the table. (sorry for my english)
This will be good or bad?