Looking for temporary use of a zero clearance throat plate for 3D modeling

[jlmeredith]

Here is a link to the casters I picked up on Amazon - https://www.amazon.com/dp/B07QRH8VS2

[d_meister]

Great solution, looking good. Good deal on the wheels, too. Those things have been very expensive whenever I've seen them. The beauty of those casters is that they allow for easy "parallel parking".
I haven't gone further with trying to print the Zero plate sections. After other warping issues on different larger prints, I've concluded that an enclosure will be necessary for my printers.

[jlmeredith]

Quick update so others do not think this is dead.

I have had some other moonlighting projects that have had priority, on of which is about to require the saw.

I use my track saw a lot, but I have a project coming up that I need to be able to cut things on the Ryobi (Lots of angular cross cuts).

But I needed to solve the mobility issues first. A$30 later I have a robust ability to drop the table saw anywhere and then store when not needed.

Need to reinstall rails. I may design some 3D printed storage spaces under the rails. Some simple joint and corner profiles with hardboard could provide good storage for things like table fence, wrenches, etc.

[LCHIEN]

The pins worked as well, but if I can make it work without them, I would like the design to be print and done rather than having hardware. I will post photos once I have tested things a bit more!

I can understand that!

[jlmeredith]

I should have some updates on this in the next day or so. I have tried a couple of options, including the pins that LCHIEN mentioned. I think I should be able to get away with just creating the joint using tight fit tenon joints that are just made of plastic. I will possibly provide the option to use a small set screw from the bottom that will lock the pieces together. The pins worked as well, but if I can make it work without them, I would like the design to be print and done rather than having hardware. I will post photos once I have tested things a bit more!

[LCHIEN]

Or make the dovetail horizontal instead of vertical to ensure best alignment vertically.

[jlmeredith]

Excellent recommendations! Thank you! I think my current approach will be to create a mortise and tenon joint that a couple of small M3 screws can be tightened up into using some heat press inserts. Low cost and easy. If a person wanted to just insert the parts and glue, that would work just as well. My goal is to ensure that the top surface with use does not move from being flat.

[mpc]

Another idea: in the pic Loring used in post #43 what if the ribs, running the length of the insert, were made into lap joints? That would provide more glue surface if glue were used... or one could drill vertically through the lap joint for a small screw, a pin, etc.

Another idea: instead of a dovetail on the upper surface, make that a butt joint or a small lap joint. Put dovetails in the long ribs.

mpc

[LCHIEN]

yeah, yeah, I know that story... make money by day so you can play at night.

Retired, I just spend money and critique other people day and night.

[jlmeredith]

LCHIEN and d_meister - all of these suggestions are very helpful! Thank you! I am unfortunately tied up with delivery of a project in my day job right now (software engineer) but as soon as I get this out the door I will be circling back.

[LCHIEN]

One potential problem with spring roll pins is that the tension to compress them may crack the plastic part when you drive it in... you can compensate for this by measuring the roll pins and making the hole oversized (greater than 1/8" but less than the uncompressed OD so as to reduce the compression forces. There's probably some drawings for the uncompressed size of a roll pin or you can experiment empirically. Ah, here, found some data.



OK, I know very little about 3-D printing, so take my suggestions with a grain of salt and ignore anything that doesn't apply for 3-D printing. You're doing a great job so far.

Loring

[d_meister]

The trouble with 3D printed structures are that they are usually not made with a solid infill. There is usually an internal grid structure with voids inside the printed object. The result is that machining or fastening is problematic. A self-tapping screw is likely to hit more air than plastic. Threaded holes can be designed in, but a common approach is to set brass threaded inserts into the plastic with a soldering pencil. Parts can be printed with 100% infill, but is rarely done with large pieces because the print would take a very long time, possibly in the area of days. I've had regular large prints with 15% infill take over 10 hours and run overnight.
I don't mean to argue for or against an approach, just pointing out that 3D print engineering and design is different than what we're used to in the woodworking world. But, like woodworking, the fun is in creative problem-solving. One of my favorite 3D printing YouTube channels is CNC Kitchen. It's by a young German engineer that runs real tests on just about everything 3D printing related. As an Engineer, Loring, I think you'd really enjoy it. Here's a video on fastening with designed-in threads, machining, and inserts:
https://www.youtube.com/watch?v=iR6OBlSzp7I

[LCHIEN]

Looks great!
Maybe just glue the joint. There will not be a need for disassembly, so just slap it topside down on a true flat surface with glue and hold it in the aligned position until set. Definitely work on the screw support area to prevent deformation. If there's enough thickness there, maybe make a counterbore to set in a pan head screw head. A flat head screw will always deform relatively soft plastics by trying to force a cone through it.
I like the mechanical engineering approach Loring suggests. I look forward to your progress with that, Jamie.

Good point about the counterbore hole... plenty of meat there and a flat heat tends to be hard on plastics. A pan head machine screw is easy enough to get.

I question a glue approach... getting the right amount of glue into a tight precision joint like the part will have is iffy, nor sure what glue to use. A solvent glue or super glue risks setting up too quickly while you are trying to get the parts perfectly vertically aligned. The tension joint of the roll pins is good for near perfect alignment in all axes and there's no force on it when the plate is bolted in with four screws. Its not coming apart in normal use or handling.

Another idea I had was a variation on the pocket hole joint. A angled (typically 15 degrees) threaded hole could be made where I suggested putting the roll pins. A self-tapping pocket hole screw with a head could be used (maybe iffy if a dado head is used) or a long skinny set screw could be used... although the ability to put 3D print a threaded hole is probably not possible. But its really to give some tensile strength to the joint that it probably doesn't need. The roll pins give it plenty of shear strength and alignment.

[d_meister]

Looks great!
Maybe just glue the joint. There will not be a need for disassembly, so just slap it topside down on a true flat surface with glue and hold it in the aligned position until set. Definitely work on the screw support area to prevent deformation. If there's enough thickness there, maybe make a counterbore to set in a pan head screw head. A flat head screw will always deform relatively soft plastics by trying to force a cone through it.
I like the mechanical engineering approach Loring suggests. I look forward to your progress with that, Jamie.

[jlmeredith]

This is a great idea!

The current joint was strictly for the purposes of prototyping (and it would work if glued I think), but now that I feel pretty good with where this has landed, I will look at better options for the joint.

I like the idea of the roll pins as it only requires a hole on each side in a solid body segment. I just ordered a 25 pack and will start adjusting the design to include their use. I will update once I have a working sample!