3D Printing for Discontinued SMT "A" Slide?

[cwsmith]

I would think the part would be difficult to mill, if only because of its very small size and how one might retain it to the bed while trying to tool it.

Paul,

Good to hear from you. Yes, I will take a wider view photo in the morning. To answer your question about why the slide has this particular form: It appears to me that it would be difficult to install or replace the Slide if A and B were a single piece. As it is, you remove the SMT assembly from the saw and flip it upside down on a bench (actually, I hold it on its side so I can place a socket on the top locknut while I loosen, or turn to adjust, the screw. Once the nut is removed is removed from the top side, I lay the top face down on the bench...that is how you see it in the photo.

You can the pull out the screw and lift off slide B. Slide A is captured under the lip of guide tray (not sure if that's the proper name). While a single piece probably would work, I think it might be more difficult to mold, but certainly a challenge to print.

I don't understand why either Slide should be susceptible to breakage, short of dropping the SMT or slamming something sharply down on the table. I can see it wearing if you use the SMT a lot. But, you can turn either Slide 180 degrees to gain a new slide edge.

CWS

[capncarl]

As far as holding the small piece while milling, that is no problem, mill it out of a larger piece that is securely fastened and leave the outside profile cut till last.

[atgcpaul]

To answer your question about why the slide has this particular form: It appears to me that it would be difficult to install or replace the Slide if A and B were a single piece. As it is, you remove the SMT assembly from the saw and flip it upside down on a bench (actually, I hold it on its side so I can place a socket on the top locknut while I loosen, or turn to adjust, the screw. Once the nut is removed is removed from the top side, I lay the top face down on the bench...that is how you see it in the photo.

You can the pull out the screw and lift off slide B. Slide A is captured under the lip of guide tray (not sure if that's the proper name). While a single piece probably would work, I think it might be more difficult to mold, but certainly a challenge to print.

OK, thanks for the explanation. That is clear now.




I marked up your picture from before. Do the oval towers on Slide B (marked by white and red arrows) serve any purpose? I can see they are necessary for Slide A because they provide spacing for the black tray, but I don't know what purpose they serve for Slide B.

Here's the idea. Where I have placed the 4 black circles, Slide B is redesigned to be flat on the bottom and notched at those circled locations. Slide A is also redesigned so at those circled locations, an additional pillar is added on top of the Slide A columns to engage with the now vacant locations on Slide B. That will accomplish that positive engagement you need between between Slide A and B.

There's also that little speed bump on the two bottom edges of Slide B that ride on the black tray. From an earlier illustration, it seems that the bottom of Slide B is slightly raised up over the black tray and only the raised bump touches the tray. I suppose that minimal contact point may be important to reduce friction? That bump will be hard to print. How about the 2 support columns on Slide A are reduced in height by the height of that bump? That will put that whole bottom edge in contact with the black plate. I can't imagine that little bit of extra contact is going to cause a problem, right?



Finally, since we can only reliable print Slide A, that only helps people with broken Slide As. If both Slide A and B are redesigned like described above, then people will need to get both the new Slide A and B because the new ones won't be compatible with the old Slides. Ultimately I think the best solution would be to create one SlideA-B. The two pieces would be identical and interchangeable. If those two oval towers marked by white and red arrows aren't necessary at all, then I can see how this could be accomplished. If the slides are made wider along the length of the black plate, does that negatively impact anything? Here's what I was thinking. This is truly a back of the envelope sketch. This is SlideA-B viewed from the top. It's made perfectly square and you create two square columns diagonal from each other with the hole through the center for the screw. This piece would mate with another Slide A-B that is turned 90deg to it. This design would also give you 4 wearing edges instead of 2. I also like that if I needed to fix the SMT (not that I do), I wouldn't have to figure out do I need SlideA or B and more importantly, do I have the one I need?

Paul

[atgcpaul]

As far as holding the small piece while milling, that is no problem, mill it out of a larger piece that is securely fastened and leave the outside profile cut till last.

For Slide B, you'd have to hold it securely for both faces of the part.

[cwsmith]

Paul,

Thanks for your insights with this.

Looking at the marked up photo, about the only purpose that I can see to those "oval towers", would be to reinforce the wafer-thin bed that the screw rests against when it is tightened. At first I thought that Slide B might pinch if tightened too much, but the fact is that the screw is designed with a shoulder so it basically only holds the Slides in position. There is a external-tooth lockwasher and a nylon insert-type lock nut which retains the bolt from the top of the table. If you removed those towers, you'd basically have a flat rectangular washer. I'm thinking that the extra reinforcement would be good (but really no reason why) and if we make the bottom of Slide B flat, their existence doesn't present a problem for the printing, except perhaps the little extra filament it uses. Here's a picture of the SMT mounted:



Regarding your idea, if I understand it correctly. The four notches you suggest would certainly work in a redesign. If you look at the previous page where I have drawn a comparison between the existing and a redesign (the illustration with the red and green cross-sections), I have basically reversed the notch and pin arrangement between Slides A and B. That would place the pin on the top of Slide A and the notch to the bottom of Slide B.... thus having both Slides with absolutely flat bottoms, which should facilitate 3D printing. The notch in the bottom of Slide B would provide only a very slight "bridge" of 0.090" which, I am thinking, would be very minor. While it is not the four notches that you suggest, two would be less of an issue. Here is a photo of how the Slides and mounting hardware are arranged, note that the Nut would be on the top of the table though (this is only the pivot mounting screw, the three "eccentric screws look slightly different):



I agree with your appraisal of the "speed bumps" and in the redesign I have removed those from the bottom of Slide B. For 3D printing, it seems absolutely necessary that the bottoms of the Slides be flat. As you mentioned, that extra contact area, with the 'speed bumps' gone, should cause no problem.

Here are pictures of the overall SMT from the bottom, and also how the Slides are installed:



So at this point I've just finished the detail drawing of the revised Slides. Later this afternoon I hope to complete the SketchUp drawings for those and will make the solid conversions through the AutoDesk "123 Design" software.

Since the screw holes on the Slides that you sent me required some reaming, I am going to make those holes slightly bigger, by about 0.004. That should do the trick without causing any problems I hope.

I'm going to send you a private note with my telephone number.


CWS

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[ballard770]

Hi gang,

Wow, what a bunch of creative guys around here. I'm afraid that I got this started on another thread and then Hank Lee picked it up with his comments about starting a new thread about using a 3D printer to make the elusive Slide A.

I just recieved a few Slide B parts that I ordered thru Ryobi's parts outlet (Gardner) and guess what? They are completely different from the old Slide B but they are marked 661845001 as what is in my illustrated parts list. I didn't go thru all the posts on this forum to determine if anyone else has discovered this.


The replacement slide looks like it may be a little more robust and i assume that it will be compatible with the old slide A as well as the slide a being created for 3D printing.

After i get back from a meeting later this PM I will take photos of the new one and post it on this forum.

Lee

[cwsmith]

Thanks Lee,

This is news to me, and I'm looking to see what the new slide looks like. It would also be nice to know exactly what the problem is with the old slides... how are they breaking, where is wear, etc. Knowing these problems with an old design would be helpful in designing something to replace them.

Paul (atgcpaul) made a very keen observation in one of his last post regarding the actual shapes of both A and B Slides. While I redesigned both slides so that they are both flat on the bottom (so they'll 3D print better), Paul suggested that the slides could be square, so that you there would be four equal sides for wear, not just two as they are now. Perhaps more important was his idea to make just one slide design, which could be used in both positions, A and B.

Giving some thought to that, I think we've come up with such a design. It's a single design that would basically mate two pieces together in either top or bottom position. It will replace the old slides altogether, as they won't mate with them. But, being a single design, you can use them top and bottom, rotate them as needed to each provide four wear edges. So even if you wear out all four edges on the top slide, you could then exchange it with the bottom slide for four new edges.

I'm in the process of finalizing the drawing and will send it to Paul this afternoon for his 3D printing and further testing when he returns to work and can fit it into his busy schedule. I'll post a sketch as soon as he lets me know what he thinks.

CWS

[atgcpaul]

CWS, sounds good. Looking forward to the new design.

Paul

[ballard770]

Sorry it took me too long to finish a bunch of Spring related honey do projects outside yesterday.


These are the Slide (B) parts that I just received from Gardner who handles spare parts for RYOBI.




As soon as I have had my coffee and checked email, etc I will go to the garage and install the slide on my SMT.


Lee

[cwsmith]

Interesting, but I don't see any real improvement here. While the bottom is the same, the top simply has the "towers" extended out to the edge and then they've added those four pins. The so-called "towers" could be to re-enforce the edge that rides against the edge of the miter base (tray), but it doesn't actually touch the edge in any way. Re-enforcement of the edge of Slide B would only be necessary is that part of the Slide is subject to breaking. I'm not sure if there is such a problem though. Other than that possibility, none of the additions offer any advantage or use from my perspective. Oddly, the original Slide B has slight indents at the positions where those new pins are. The indents are round, like the pins, and are countersunk only by about 0.008 inches. (No function to these indents either.)

Does make me wonder even more about how this part fails, so if any members have some experience and insight into the wear and/or failure, please jump in here and let us know!

CWS

[ballard770]

I just replaced several new design slide (B)s on three SMTs. It appears that the new design does have a little more 'meat' in the contact area as the raised edges extend to the end of the slide in the contact area and the posts close to each corner may also provide additional sturdiness.

Additionally, it appears to me that the Slide (A) has more support in the area under the contact with the underside of the sliding portion of the SMT as it is aprox 3/4" in diameter that covers much of Slide (A)'s contact with the sliding lip on the top. Out of the three SMT's that I have, none required a replacement of Slide (A) but six Slide (B)s needed replacement. Even though someone posted that the original Slide (B) shouldn't fail under 'normal' use it appears to me that part of using the SMT means removing it and storing it and then re-installing it for use. In my case that was rather frequent but now I generally use my BT3000 for ripping rather than crosscuting/mitering as I have a 10" sliding miter saw for that purpose - the Hitachi sliding miter saw seems to do a more precise crosscut and miter than what i can get on the BT3000 SMT.

I hope that the 3D printing guys keep up the good work but apparently there may be more need for 3D printed Slide (B) than the Slide (A) that everyone has focused on. At some point in time there may be no Slide (B)s available from RYOBI (Gardner).

Does anyone have a method of cleaning the aluminum on the SMT as well as the Accessory Tables? Mine look like heck, even though they work it would be nice to be able to clean them up. I may try Bartenders Friend or Aluminum Wheel Cleaner/polish.

Lee

[cwsmith]

Here's a couple of screen shots for two "Universal" designs that I've layed out from Paul's suggestions: The first is my interpretation of his description and the second is what I see as the sketch that he did. I think I actually like the second image better and it would be far less complicated to print in 3D I think:



The above image shows the single 'universal'' part in foreground with two mated parts in background, you can see the bottom on the upper right.



This was from Paul's sketch, at least as I see it. The part look pretty easy to print and by just flipping one piece over, it mates quite nicely with the other.

Either of these designs would provide would provide four wear edges for each piece an they could be exchanged to ride in either upper or lower positions.

When we get the parts printed, we'll see how well they work.

CWS

[atgcpaul]

Here's a teaser pic. I'll write up my observations hopefully tonight after work.

Paul

[cwsmith]

Paul,

Those look pretty nice, though I miss the "red"

From the photos, the redesigned two-piece A and B slides (upper left) look like they came out pretty well and should work nicely together.

My design of a the 'universal' single-design (upper right), stacked on top of each other looks to be a bit of a problem. While the top is well pronounced, the bottom is going to require a little manual work to clean up the 'socket' holes for the pins to fit into. While I think that would provide a stable fit, that extra amount of work would be a production challenge.

Your design (the bottom four pieces) look absolutely great. No pins or sockets to snarl the printing process and it looks like just flipping one piece over makes a stacked-fit perfectly without any further hassles.

Of the three designs, I think yours is no doubt the best from all three designs. It's simple, easily printed, and no manual after work. Provided the fit is snug and not rocking (a printing problem, not the design itself) I think we've got a winner here. Thanks Paul.

Let's see how those fit together on the SMT and then we'll make the drawings available here on the forum.

What is the objective of all this? Having the ability to local source a part that is either not available or in short supply. From what little I know so far, almost any area should have a source for 3D printing and within a year, a 3D printer should be available from local stores. For now, a Google search for "local 3D printing" found a few hits. I found this one " https://www.makexyz.com/ " and discovered two sources within a mile or two of where I live. What it costs, I don't have a clue, but it should be cheaper than ordering them I would think. I'll do some more exploring.

Let me know what you think Paul and I'll make dimension detail drawings for the part and post those here as PDF. Also will include the finalized SketchUp and the 'STL' export files too.

CWS

[atgcpaul]

I think the reversible part wins for the reasons you stated. While playing with the new printed pieces, I found that the little nub at the very top of Slide A (upper left pieces) broke off rather easily. That's not a big surprise because these are printed in layers and without a lot of surface to surface contact at that point, there's not enough adhesion.

The fit for the reversible piece is snug with almost no wiggle. I am pleased with how they turned out.

CWS, before you post the final drawing, let me send you the parts for you to evaluate. The part I drew up is slightly taller than the one you did.

I went to the website where Lee bought Slide B. They were just 97cents each--not sure about shipping. IIRC, there were about 200 in stock. Lee, did they sell Slide A, too? Personally, though, if I still owned a BT3, I'd probably buy a couple sets of those slides and hold on to them for a rainy day.

Paul