BT3k's, Sharks, and Tenryus, oh my!

[Schleeper]

A nearby cabinetmaker closed up shop recently, so last Saturday I went up to see if he had anything I could use. The maple lumber he had was gone by the time I got there, and the tools were way out of my league. However, he had some barely used saw blades that were of interest. Two Forrest blades - 30T WWII and Duraline Hi-A/T - looked like they'd barely had the wax coating removed from their carbide tips, but it was the Tenryu Gold Medal 40T that caught my eye. I'd heard some pretty nice things about the Tenryu, and the cabinetmaker absolutely raved about it. So, even though the Forrest blades were probably a better buy, and the Tenryu had obviously been used more, the Japanese blade is the one that went home with me. (Besides, I already own the two Forrest blades.) After a little cleaning and waxing, it could have passed for brand new.

I have no idea why I felt the need to buy another blade; the 30T TK WWII I'm using cuts through hard maple like it's butter. If it ain't broke...

Anyway, I tried two rips with the Tenryu - on oak and maple - with very unsatisfactory results. Feeding took more effort, and then much more effort, causing me to stop halfway through both times to avoid broken belts, hellacious kickback, or both. I finished the cuts by starting from the other ends. That was enough; I put the WWII back on, and picked up where I'd left off.

Now I'm trying to figure out why that happened. At first I assumed that the riving knife on my Shark Guard is to blame. It's the standard size .090" thickness that works well with thin kerf blades, but the Tenryu is neither FK or TK; it measures .111". Would using the .105" thick riving knife solve the problem? (Lee Styron: what do you think?)

How important is centering the riving knife? I just popped the WWII off and the Tenryu on, without changing the position of the knife. Could that have caused, or contributed to, the problem? (BTW, at that time I had all the shims to the left of the riving knife, but I have since moved one to the right. What setup do y'all use with TK blades?)

I suppose the fact that the Tenryu is thicker than the WWII, and has 40 teeth vs. 30, also plays a part. (I have one of the older 13 amp BT3000's, sharing a 20A circuit with the HF DC.) If that turns out to be the most likely reason, however, I guess I'll be getting rid of my other WWII - the 40T FK.

Another possibility, I suppose, is that it needs to be sharpened. I've pretty much discounted that, though, because I don't believe that would cause the saw to bind the way it did. For that to be the case, I should think the wear on the carbide tips would be readily apparent to the naked eye. I didn't even detect any using magnification.

[master53yoda]

the DC and saw on the same circuit is a problem if the DC is getting near full airflow.

The DC motor will draw away from the bt3000 motor because it is an induction motor and speed is controlled by the 60 HZ where the bt3000 motor is a brush type universal motor that slows down as the voltage drops.

added together they exceed the 20 amps.

put the DC on a different circuit and see what results you get. the bt3000 needs to be on its own circuit to prevent voltage drop under load.

[Black wallnut]

40 teeth is a bit much for rips in hardwood that may be your biggest issue. There could have been tension in both boards adding to the problem and the 13 amp motor probably does not help. I've not expermented with moving my RK but I don't see it making much difference unless the kerf is trying to close and in that situation it would be better if it was closer to the fence IMHO to reduce the possibility of kickback, as opposed to lined up with the far side of the blade. Centered behind the blade would be best.

Good catch master53yoda! BTW I'm a NCHS class of '82

[cgallery]

I think if the blade is cutting a wider kerf, the riving knife shouldn't be a problem.

I'd use the SMT to cross-cut some 12" plywood with no riving knife in place. The results should eliminate (or not) the RK as the culprit.

Some blades feed easier than others. I've found the DeWalt (yellow) blades the easiest to feed on my BT3K. The WWII blades are right up there, too (with a better finish, I think, than the DeWalt blades). Freud blades have required substantially more feed pressure than the other two. And dull blades, well, the BT3K isn't powerful enough for dull blades.

Finally, raising the blade a higher can reduce feed pressure requirements (at the expense of the loss of safety from a more exposed blade).

[LCHIEN]

my HF DC draws 14.5 amps by itself. My BT3000 15A model draws 6 amps just spinning, unloaded, not cutting. Adequate motor amperage is a real question for your setup.

You can check your riving knife issues by simply trying to make one rip cut without the knife. Just be extra careful.

[pecker]

I had been using a Tenryu blade with a microjig splitter

When I got A Ridge TS2000 I just assumed the thicker kerf would meen the splitter would be a bit less effective.

But when I put on the blade and tried to make a rip cut, the board got stuck as it passed the blade. It hadn't occurred to me that the thicker plate of the Ridge would actually put the center of the cut in a different place than the Tenryu.

You may be having the reverse happen.

[Knottscott]

I've had two Gold Medals, and two 40T WWII TKs, and have used the 30T WWII TK....I think the two 40T blades are comparable designs and have comparable performance when new. Kerf width and sharpness will both impact feedrate. The GM has 33% more teeth than the 30T WWII, and is ~ 11% thicker....both significant enough differences to notice. Sharpness could also be a contributor. It's worth spending $15-$20 to have the GM sharpened IMO.

[Schleeper]

my HF DC draws 14.5 amps by itself. My BT3000 15A model draws 6 amps just spinning, unloaded, not cutting. Adequate motor amperage is a real question for your setup.

You can check your riving knife issues by simply trying to make one rip cut without the knife. Just be extra careful.

I wasn't aware that the DC is such an amperage hog!

OK, I've got two circuits to work with - one 15A and one 20A. We've got a second refrigerator/freezer that has to be plugged into one of them, and I get what's left. Which item gets the 15A circuit all to itself?

[Black wallnut]

John is there a reason that makes wiring in another circuit out of the question?

[master53yoda]

A 2 hp DC with large enough piping and full air flow will draw about 17 amps

Good rule of thumb for induction motors is 9 amps / HP at 110 VAC 4.5 amps / HP on 240.

DC HP usage is based on static pressure X cfm. the more restriction the less cfm the less HP required.

The DC that was drawing 14.5 is delivering a little over 1.5 hp and about 900 to 1000 cfm.

Both the DC and the BT3x00 should be on individual dedicated circuits.

My shop has 3 dedicated circuits The BT300, 2 hp DC, and 3 hp Compressor.
I have 2 other 20 amps circuits in the shop plus a 15 amp lighting circuit.

I put a 60 amp 240 vac sub-panel in the the shop. You could probably get away with a 30 amp 240VAC sub-panel in a one person shop. The LOML works in the shop with me much of the time, that is why everything in the shop is set-up for 2 tool operation.

[Stytooner]

That RK should work for all carbide tipped blades up to about 1/8" kerf. Haven't tried it on thicker ones with larger blades. Those guys get thicker splitters.
When you change blades, it's quick and easy to throw a straight edge up beside the blade to see if the knife is in place. Check both sides, then you know it isn't the knife.

Not saying that you would do this at all, but some guys have actually mounted a new blade backwards. The proof is in the forum history somewhere.

[dbhost]

That RK should work for all carbide tipped blades up to about 1/8" kerf. Haven't tried it on thicker ones with larger blades. Those guys get thicker splitters.
When you change blades, it's quick and easy to throw a straight edge up beside the blade to see if the knife is in place. Check both sides, then you know it isn't the knife.

Not saying that you would do this at all, but some guys have actually mounted a new blade backwards. The proof is in the forum history somewhere.

Say it isn't so!

[Schleeper]

Say it isn't so!

Actually, I just did it this week. I had to make a new ZCTP, and I used a 7-1/4" blade to make the initial cut for the kerf. I was on autopilot, apparently, because I put the blade on the arbor with the nameplate facing me. Of course, circular saw blades have the writing on the other side...

[Schleeper]

John is there a reason that makes wiring in another circuit out of the question?

An explanation is probably in order.

I don't have a "shop" per se. When I took on the project of making our kitchen cabinets, I moved my BT3000 and shop vac from the basement (unfinished, and only accessible by stairs from the kitchen) to the 2-car garage. I started work using just the 4 outlets that were out there already - the two on the ceiling for the garage door openers, which share a 15A circuit with outlets in the master bedroom; the GFCI outlet that's on a 15A circuit with the three bathrooms, the back deck, and the sump pump; and one on a third 15A circuit that includes all the outlets in the family room (with its array of a/v equipment.) Not the ideal scenario, obviously. THEN, we moved the refrigerator out there, and I bought a planer and DC, prompting me to have two new circuits added (the 15A and 20A that I've aready mentioned.)

Our original plan was to use the refrigerator on an intermittent basis, but you know how that goes. With it being winter and all, I suppose I could just unplug the refrigerator when I'm working out there. But that's a pain in the butt, and sure as anything, I would forget to plug it back in when I'm done for the day.

If all goes well, I'll be done with the cabinets in a few months, and the garage will revert back to the place where we store our cars. All the power tools will end back in the basement. So there's not a lot of support for the idea of adding more power in the garage.

[master53yoda]

Put the DC and the frig on the 20 amp circuit The frig HP is about 1/3 HP and the DC will run with it. If you blew the break on start-up of the DC which is doubtful, you would be aware and the frig would get turned back on. About the only way you would pop the breaker is if the frig and the DC started at the same time.

The bt3000 or the planer because of the universal brush type motor is affected more by the voltage drops then the DC is but does not have the amp draw that the DC does. They should run ok on a 15 amp circuit.