SMT Deflection?

[furthermore]

Hi all, long time listener, first time caller. I've had my BT3k for about a year now and after chasing down perhaps every possible issue I could have had (misaligned SMT, missing SMT clamp, broken shims, misaligned rip fence, many missing parts) I now feel as though I've finally got my saw in decent shape.

I've recently replaced my SMT guides with 3D printed ones from Ebay, and followed the procedures for alignment (using the JP Thiel method with the dial indicator, down to ~1-2 thou off or as close as my cheapo dial indicator will get me). All that to say, I think that I should be able to get reasonably good results out of this thing now.

The issue I'm chasing down now is deflection of the SMT fence when tightening it down. I'm trying to set the fence to 45 for making mitered half-lap joints for picture frames. I'm noticing that I've got a significant amount of deflection that's making it difficult to achieve a nice 45. It's not just cutting miters either, when I set the fence against the 90 stop I have to really hold it in place to get it to sit flush. What can I do to remedy this? I've got the aftermarket aluminum fence clamp (also ebay) because when I bought my saw it didn't have one (and I didn't know better at the time, just got the saw for ~100 bucks from a neighbor)

I'm assuming I'm not the only one over the years to have this issue, so I've come for some help! Thanks in advance!

[LCHIEN]

I seem to recall some people having a warped SMT that crowned in the middle where the SMT clamp or miter holder was tightened. Check with a good level and make sure your SMT is flat. Don't recall why this happens....

Another thing is the little black pivot that slides along and in the bottom of the miter fence that plugs into a hole on your choice of the left or right (I have always used right) of the SMT... You do have one? If you don't its impossible to hold the miter fence in position after locking it. See attached pictures.



Are you using the optional accessory overarm miter clamp (not the holder you replaced)? When using that, the way it works, it tends to want to move the miter fence a bit so you have to tighten the miter holder a bit tighter than when not using the miter clamp.

[furthermore]

I do have the black pivot!

I'm also wondering if the previous owner (or one before that?) had cranked the knob down wildly tight and deformed the aluminum on the underside of the table.

I'm going to look into the t-bolt mod described here https://www.sawdustzone.org/forum/di...r-grip?t=38224 (I have some kicking around) and clean up the channel with some scotchbrite if it's got crud in there.

I've been reading through this vintage thread https://www.sawdustzone.org/forum/di...-the-smt-again and it strikes me that Sailor and I may be having similar issues. I'll read it again to see if there is some knowledge to be gained. This forum's longevity is astounding. There's so much knowledge in here!

[LCHIEN]

I think that was one of the other problems someone once used a flat washer under the head of the bolt on the bottom of the SMT in the channel and it did not hold well. I think just a naked hex head is used.

[furthermore]

Checked the underside of my SMT, doesn't look terribly chewed up, and there's no washer under there. There is a washer under the knob, but I think that's factory spec?

I'm contemplating making my own "fence" for the purposes of finishing my frame project. I'm thinking a 1x3 (or so) held in the pivot point with a dowel and a hole for a bolt should get me close. Then I can use some of the toggle clamps I have kicking around to hold my work piece down while I'm making my half-laps.

Thank you for the tip about the crowning, I'll check that for sure.

[leehljp]

Just to be clear, and some in the past, including me early on, missed the importance of the placing of the black PIVOT PIN. A few of us did initially place the pivot pen into the long slot. It does NOT go into the long slot, but either of the two holes on the side.

Apologies if you got that, but I for one, and a few others early on (years ago) missed this. Our resulting problems sounded much like the one you are having.

[furthermore]

No worries, thank you for the advice!

I've had a spare moment to get out into the garage (found the back door wide open, too, letting in the nice snowstorm we're having at the moment) and I think I may have resolved my issue!

Since I have the machined aluminum SMT clamp replacement, I figured that I might try taking out the washer in between that and the knob, and what do you know, it seems to work! I'll have to verify the accuracy with some test cuts, but I was able (using the orange indicator on the fence) to see that I could firmly tighten the knob and not have any wander. Again, I'll need to verify the accuracy and precision of the angles, but it seemed to be better

[nicer20]

Hi all, long time listener, first time caller. I've had my BT3k for about a year now and after chasing down perhaps every possible issue I could have had (misaligned SMT, missing SMT clamp, broken shims, misaligned rip fence, many missing parts) I now feel as though I've finally got my saw in decent shape.

I've recently replaced my SMT guides with 3D printed ones from Ebay, and followed the procedures for alignment (using the JP Thiel method with the dial indicator, down to ~1-2 thou off or as close as my cheapo dial indicator will get me). All that to say, I think that I should be able to get reasonably good results out of this thing now.

The issue I'm chasing down now is deflection of the SMT fence when tightening it down. I'm trying to set the fence to 45 for making mitered half-lap joints for picture frames. I'm noticing that I've got a significant amount of deflection that's making it difficult to achieve a nice 45. It's not just cutting miters either, when I set the fence against the 90 stop I have to really hold it in place to get it to sit flush. What can I do to remedy this? I've got the aftermarket aluminum fence clamp (also ebay) because when I bought my saw it didn't have one (and I didn't know better at the time, just got the saw for ~100 bucks from a neighbor)

I'm assuming I'm not the only one over the years to have this issue, so I've come for some help! Thanks in advance!

Just read the entire thread and glad you resolved the issue.

I am just trying to understand the original problem of deflection. Can you please share any photos or even a hand drawn figure to explain the problem.

Thanks in advance.

- NG

[LCHIEN]

Just read the entire thread and glad you resolved the issue.

I am just trying to understand the original problem of deflection. Can you please share any photos or even a hand drawn figure to explain the problem.

Thanks in advance.

- NG

I think historically (been a long time) there were some complaints about non flat SMT with what was reported as a crowning in the center causing cross cut parts to teeter totter while against the miter fence. Also its my recollection that it made the miter fence hard to lock into position.

Usually IIRC the problem was some hamfisted guy would crank down way too hard on the miter holder knob that locks the miter fence because he left off the black pivot and it wouldn't stay in position... or as BW recollected he had the black pivot placed uselessly in the slot rather than the side location holes. (true story - I recall a thread where the guy was saying his miter fence would not stay in position and finally resulted in SMH's from all the seasoned users when they realized he had the black pivot in a useless location).

And then I recall there were some issues when people added hardware - extra washers specifically - in the wrong places, under the bolt head below the table or in between the table and the miter fence.

I haven't heard this issue in 15 years when new owners were carrying them home from Home Depot a 5 hundred a week*. I wouldn't worry about it.

* its been said they sold a several hundred thousand of the BT3 series and they sold them from about 1993 to 2006. If you take 13 years time 52 weeks and divide that into 200,000 I get 320 a week and that assumes level sales. I know there were years where they pushed them relentlessly while other years it was low key. So I'm guessing around 2000 to 2003 peak of sales they were flying out the doors at 500 per week.

[nicer20]

That must have been stellar sales. Makes me wonder why would Ryobi discontinue a product in such high demand. Or may be that is still a small number for large manufacturers.

BTW do you know what was the retail price of this saw? $500? (I bought mine used so don't know).

NG

[furthermore]

Just read the entire thread and glad you resolved the issue.

I am just trying to understand the original problem of deflection. Can you please share any photos or even a hand drawn figure to explain the problem.

Thanks in advance.

- NG

Oh sure! It's very reproducible. I'll do my best to take a video once I'm done working for the day. I'd go do it now, but as a work-from-home-er, I do try to not indulge my desires to fart around in the garage all day instead of doing my actual job. It helps that it's about 40 degrees out in the garage right now and I'd have to run the heater for a few hours for it to be "comfortable in a sweatshirt" warm out there.

[LCHIEN]

That must have been stellar sales. Makes me wonder why would Ryobi discontinue a product in such high demand. Or may be that is still a small number for large manufacturers.

BTW do you know what was the retail price of this saw? $500? (I bought mine used so don't know).

NG

Historical price? Read my FAQ.

I think the brief summary is that the BT3000 initially cost $500 or 600 back in 1993. Prices dropped to around 400-450. The later BT3100 near the end of its peak sales in 2004-2005 was going for as low as $300 list price and of course was clearanced at sometimes lower prices than that post 2006.

[furthermore]

This weekend I decided to treat myself to an objectively correct tool, since I was unsure of the precision of the reference pieces I'd used to calibrate my saw, and I bought a Starrett combo square. Needless to say, everything was off by quite a bit. Apparently a cheapo triangle is worth about what you pay for it. A mistake I will do my best not to repeat.

I'm going to recalibrate my rails and SMT and try again to see how good I can get it.

[leehljp]

This weekend I decided to treat myself to an objectively correct tool, since I was unsure of the precision of the reference pieces I'd used to calibrate my saw, and I bought a Starrett combo square. Needless to say, everything was off by quite a bit. Apparently a cheapo triangle is worth about what you pay for it. A mistake I will do my best not to repeat.

I'm going to recalibrate my rails and SMT and try again to see how good I can get it.

I have a hand-me-down Starrett 24" from my dad. That is my most prized hand me down tool and one of my most used tools. It is still dead on accurate. Love that tool!

[furthermore]

I have a hand-me-down Starrett 24" from my dad. That is my most prized hand me down tool and one of my most used tools. It is still dead on accurate. Love that tool!

I spent a few hours in the shop last night putting in some quality time with the new square. What a difference a precise tool makes! It took me about 2 hours for the whole procedure, but I finally FINALLY have the rails and SMT set correctly! I was able to get a dead on square cut with the fence at 0 and a perfect 45 miter, both checked against the Starrett. I've got my fingers crossed that I won't have to do the calibration procedure again for a while, but if I do, I think I have the hang of it now. Hopefully next time I have to do it, it won't be so cold out in the shop! The cold aluminum will really suck the heat right out of your hands.

[dbhost]

Glad to know you got it "squared away"! (Pun intended)...