Aftermarket SMT

[Black wallnut]

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[Black wallnut]

Do let us know how well they mate up with your original(?) B slides.

I'm still surprised it was your A slides instead of your B ones that broke up, since the A's are about double the thickness of the B's. It was my B slides that cracked up, which until now I thought would be the norm.

The parts will be identical.

[Black wallnut]

Does "will be" indicate an assumption on your part?

I know how manu's love changing things ever so slightly between OEM and house re-badged products. Also, designs do get altered occasionally.

I haven't heard back from the Ryobi sources who were going to research everything there is to know about these (and rip block) slides, including design and material changes, if any, between production runs. I think they went and forgot about lil ole me after they confirmed the OEM slides are (or at least were) Delrin.

Seriously? I have been around this forum since the second month and spent several years at forum that Ryobi had before that. In that time it is fair to say that every single part of every variation of saws has been discussed in depth. Based on that if they were different in any way it would have risen to the surface and it has not. Sears has been an alternate parts source for years. Even though they have several variations of this saw the SMT slides have been the same. If you wish to classify that as an assumption on my part that is your choice. I have been wrong before and if I'm wrong I am sure someone will come forward.

[eccentrictinkerer]

Great source of BT3 parts in Minnesota.

http://www.reedssalesandservice.com/

[mmcmac]

Then there are these. Uber cheap.

Note this would produce a quite small bearing surface between the Al miter base ways (#14) via tangent contact with the round washer sleeve. This would result in rapid wear and require frequent readjustment of the effective point contact vs. the ~20mm wide contact of the OEM design.

If some fitting will be required for off-the-shelf components, fabrication doesn't seem too far off. Attached is an update to the OEM acetal A/B (#25/#28) bearing block dimensions, calling out (page #2) dimensions for a single unified bearling block. This should require a minimum of a tablesaw, drill press, and measuring caliper to fabricate. And here the only dimension requiring fuss is the 2.75mm (0.108") dept of the upper block lip which establishes the height of the miter table top (#1) relative to the miter table extrusion (#14). Once this has been accurately setup, all sides of the block perimeter are then kerfed allowing all four sides to be used as consumable wear surfaces.

[Black wallnut]

Well, it was a question not an assertion. No offense meant.

Fair enough.

What left me with the impression that there could be differences somewhere over the course of decades is the response by Ryobi to my queries.
The support sources left the issue of possible design alterations open, while there was no hesitation in stating matter-of-factly that the material used (at least for the originals) is Delrin. No ifs ands or buts. Delrin.

I followed the link and the pics were black in color and appeared identical.

The fact that personnel who had been working for Ryobi for decades and allegedly had intimate knowledge of the BT3 design in particular needed to research the matter made the possibility of design modifications to the slides seem real to me.

Who were you contacting at Ryobi?

It wouldn't be the only plastic component that was changed.

My old rip block slides are black. The new OEMs being offered on eBay are white. The pics are a bit blurry, but they don't appear 3D printed.
The Ryobi source couldn't comment on this w/o research, leading me to conclude there could be changes involved other than simply color.

How are you sure they are OEM? First I have heard of white front block slides.

The miter fence clamp knob went through several variations. Comparing the earliest knob to the later ones, it's pretty obvious they did this to enhance grip/torque.

I've not noticed these changes, could you point me to pics showing the differences.

The rip fence roller holder was beefed up, presumably due to a relatively high incidence of cracking.

Another change I have not been aware of. Pics please. Perhaps there are variations you are including that I am not. BT3000SX, BT3100, and the Craftsman two clones, one of which AFAIK is only offered in Canada with miter slots in the SMT IIRC. The other was identical to both BT3K and BT3100 IIRC. The folding stand saws might be different, the bts15 is different.

Thus, I thought it possible they eventually beefed up the B slides if premature failure (i.e., cracking) was common. If they had done that, maybe they also changed B slide dimensions other than thickness (e.g., tabs) and dimensions on newer A slides to match.

If nothing ever changed with these slides and they all fit perfectly regardless of year or label, that's great. The inability of Ryobi to state same is curious.

With the way folks change jobs and forget stuff it is likely that there are very few at Ryobi that were there when the saw was introduced or even when the motor was upgraded to 15 amp or even when they upgraded the BT3100. The way this forum has been since it started is when a member saw a potential variation it triggered a thread and sometimes many threads. Sometimes a member would buy one and o an in-depth review of it listing all the changes as Sam Conder did with the BT3100. Back in the early days these saws were available at many places. There were a number of issues that were pretty common and the fixes were well know, so much so that Lchien suggested that a FAK committee was formed to jointly wright one. Well Sam obliged and formed the committee and gave us a private forum. The idea fizzled and finally Lchien took the bull by the horns being that he is a Texan and wrote his huge document based on what had become common knowledge among the forum regulars.

[mmcmac]

A miniature ball bearing could be used in the alternatively proposed sandwich instead of a spacer (third washer). If no stock ball bearings can be found that are the needed dimensions, then a simple sleeve bearing made up of 2 spacers and dry lube between them should work. That's assuming, of course, the stock material is available in close enough diameters to meet desired tolerances.

I had hopes the OEM slides would be easily displaced by a ball bearing. Howver wear due to maintaining SMT parallelism to the blade is lesser in practice compared to wear caused by the weight of the SMT and payload in forward/backward travel. The former (maintaining parallelism) wears the block vertical bearing surface and latter wears the bearing on the block's lip bottom horizontal surface. So the greater wear reduction candidate would be a ball bearing oriented vertically such that it rides on the miter base (#14) flange, supporting forward/backward loaded table travel. Unfortunately with 2.75mm of clearance, a ball bearing solution isn't possible. Moreover given the empirical success of the lowly acetal slide bearing, its inherent wiping of the mating way, and the minimal cost of replacement fabrication, I'd abandoned the notion off a ball bearing retrofit.