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OT: time for a new table saw?

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  • JRT
    commented on 's reply
    Another issue with old table saws is sometimes the belt is also old. An old belt, especially if unused for a long while, can take a set shape, and that can cause vibration in the types of saws that use only the weight of the motor to tension the belt, causing vibration when the saw is running. As compared to a conventional vee belt, a link style belt does not take as much of a set, and the link style belt can help to reduce vibration in the saw, but those also tend to increase noise level of the saw (runs smoother, but louder). 
    Last edited by JRT; 03-31-2021, 08:27 PM.

  • williamrschneider
    replied
    Here are a couple more thoughts about your existing table saw. I have a 1990s Craftsman contractor's saw that I'm happy with, but I'm not sure if that's the model you have. If it is, I encountered some strange noises when the motor mounts loosened a bit. On my saw, the mounts are clamps around the ends of the motor. See below...

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    Once I tightened them, my worrying noise problems vanished.

    If your belt has stretched, you may reach the limits for tensioning it, and that would bog cutting. On my saw, the motor's weight provides the belt's tension as it hangs from its pivoting mount. The slot in the mount must have some "daylight" left at the end, with the pivoting frame not bottomed out, or you won't be able to achieve enough belt tension. Also make sure that the motor can move freely as you swing it through its arc. It's possible that the bolt that goes into the slot arc is binding, not permitting motor weight to properly tension the belt.

    Those are just a couple of additional thoughts about the ongoing issue with your current saw.

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  • djg
    replied
    I ended up with a somewhat thin Diablo blade on my little ancient 8" Craftsman saw. That size is not very popular, and selection was sparse. It cuts fine. Plywood, MDF, particle board, lumber.

    JRT seems to know a lot about the subject, just wanted to pimp the Diablo. I also have a Diablo on my old cheap Skil saw. Cuts great.

    Leave a comment:


  • Liberator of Magic Smoke
    replied
    Sounds like you just need a sharp blade in there. The less powerful the motor, the more a dull blade will slow things down. If the blade you are using has carbide teeth, it will be hard to tell how sharp it is by feel, unless you have a lot of experience. Sounds counterintuitive, but it's true. There are lots of good blades out there for sale, but also some pretty bad ones. I've had the best luck in the past ten years with Diablo blades. Fortunately, they are reasonably priced. Many cheaper ones won't cut well right out of the package, and will dull really fast. I just replaced the blades in two saws at work today, with Irwin's newer blue blades as that's what the local lumber yard had. I've used them before and they seem to be pretty good. The prices are about the same as Diablo. I don't get to Home Depot or anywhere like that much these days, since it's well over an hour to the closest one and it's really small.

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  • JRT
    replied
    Originally posted by Paul Ebert View Post
    So, the arbor belt pulley was, in fact, loose. I fixed that, but the saw still isn't working well. It starts out cutting fine, but bogs down as the board goes deeper into the blade. This is with trying to cut 3/4" particle board. I've checked the alignment of the blade and the fence and adjusted them. The blade looks well used, but not too bad. I should probably get it sharpened or buy a new one (or both). I'm wondering if I have a problem with the motor. Do they need any maintenance? Are there brushes that need to be checked / replaced? It's only a 1 HP motor. Maybe I should replace that too. Or, continue to keep my eyes open for a good deal on a good used cabinet saw.
    A few thoughts on that.

    1.) Use a sharp blade, always.

    2.) Consider using a thin kerf saw blade with an added blade stiffener on your low powered saw. A thin kerf saw blade chops less wood in the kerf, does less work in making the cut, so at similar feed rate it uses less power. It has less structure, so vibrates more easily, but that can be ameliorated by using a blade stiffener which is a specialized thrust washer that is thicker at the rim than in the body. The added thickness preloads the saw blade axially deflecting it slightly in the direction away ftom the washer. That preload increases the force needed to increase that deflection, and it shortens the unsupported radius, both reducing the maximum amplitude of blade vibrations.

    3.) Do not adjust the rip fence exactly parallel with the blade. It should be very close to parallel, but the outfeed side should have slightly more clearance, no more than 1/32 inch difference. Stated another way, with the blade at maximum height, the teeth at the front of the blade should be roughly 1/32 closer to the rip fence than the teeth at the back of the blade. It should be close to parallel, but there will be some error, and that error should be on the side of slightly opening the gap toward the rear of the cut. That avoids the workpiece getting squeezed between the blade and the fence during a rip cut. Don't overdo that. Keep it slight.

    4.) Blade height requirements are different for various materials and cuts and blades, but...
    With carbide tipped saw blades, for most cuts, adjust the blade height so that the gullets between the teeth are aligned with the top of the workpiece. Rotate the blade to place a gullet at top dead center, adjust the blade height to place the bottom of that gullet even with the top surface of the material. Carbide tipped blades are designed to work best at cutting angles created by that height. The teeth near the front of the cut are doing all of the cutting, while the others drag through the kerf and generate heat. That blade height gets a lot of the teeth out of the kerf during the cut instead of dragging them through the kerf when not cutting chips. It also avoids setting the blade too high where teeth are working at inefficient angles. Excessive height can lift the rear of the workpiece which is part of the recipe for kickback, which can be very dangerous. And yes, that blade height is very different from what was used with old school blades without carbide teeth.

    Doing these will combine to create less drag in the cut, generating less heat, requiring less power, eliminating or greatly reducing any scorch in the kerf, and helping to make cleaner cuts.

    Woodworkers' Guild of America on topic of blade height:

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  • Paul Ebert
    replied
    So, the arbor belt pulley was, in fact, loose. I fixed that, but the saw still isn't working well. It starts out cutting fine, but bogs down as the board goes deeper into the blade. This is with trying to cut 3/4" particle board. I've checked the alignment of the blade and the fence and adjusted them. The blade looks well used, but not too bad. I should probably get it sharpened or buy a new one (or both). I'm wondering if I have a problem with the motor. Do they need any maintenance? Are there brushes that need to be checked / replaced? It's only a 1 HP motor. Maybe I should replace that too. Or, continue to keep my eyes open for a good deal on a good used cabinet saw.

    Leave a comment:


  • relder
    replied
    I use my band saw once or twice a year, table saw gets used on the regular. For speaker building specifically, table saw is the way to go. Smooth straight cuts and capable of handling sheet goods. But if you don't have room, you don't have room.

    I just helped a friend put together his new saw stop cabinet saw. Pretty nice. Got his with the mobile base, moves around fine.

    Leave a comment:


  • Waldo
    replied
    Its actually fairly easy to and not terribly time consuming to sharpen a bandsaw blade, you just need a dremel. Might take a while if you've got a 15+ tpi blade, but a more typical 3-4 tpi blade goes quick.

    But, using mdf if not a necessity. Esp if you have a good source for Baltic Birch ply.

    Leave a comment:


  • Paul Ebert
    replied
    Originally posted by Waldo View Post
    There is no function that a table saw can do that other tools are incapable of doing. I have a small basement shop that only has space for 1 big saw, and I chose a bandsaw instead (+ lots of hand tools), since it can both rip and resaw. Best decision ever. I find that table saws strongly color design decisions, especially among woodworking beginners. Sure the pros need em, but the hobbiest can definitely do without.
    I think you are very correct for general woodworking, though I'm not sure for speaker building. I'm not sure how long a bandsaw blade would last cutting MDF and I'd never use a good hand tool on it.

    Perhaps what I should be considering is a CNC instead of the tablesaw.

    Leave a comment:


  • Waldo
    replied
    There is no function that a table saw can do that other tools are incapable of doing. I have a small basement shop that only has space for 1 big saw, and I chose a bandsaw instead (+ lots of hand tools), since it can both rip and resaw. Best decision ever. I find that table saws strongly color design decisions, especially among woodworking beginners. Sure the pros need em, but the hobbiest can definitely do without.

    Leave a comment:


  • 1100xxben
    replied
    Originally posted by Paul Ebert View Post
    ... I really wouldn't mind having an excuse for upgrading.
    That's a good enough reason for me... You have my permission.

    Leave a comment:


  • mattp
    replied
    I've used several different "loaned" saws in my ~20 years doing this but this is my personal saw I've had for about 2.5 years. I have learned a lot about the differences but for me, a solid fence cannot be overlooked and a cast table top makes for a much smoother running saw. It's a 1.5 HP 10" Delta, non-belt driven and I got it through Lowes. This thing only set me back about 600 bucks and I feel like I got a lot for that price. It is mobile but I don't move it due to my shop setup. The fence is solid as a rock. Since building the outfeed table I will never not have one again. I am planning on an upgrade to either a Powermatic, Saw-Stop or Unisaw, I am undecided at this point, but this saw has been great for me so far and for someone looking for a mobile, safe, solid, inexpensive quiet saw I recommend it.

    My father in law recently got a Saw-Stop contractor saw with a folding base. It is a nice saw and has some well engineered features, but for the $1400 it cost I am a little surprised at how "cheap" it feels by comparison. He loves it, and I am glad he has the added safety of the blade brake. If I were to get a Saw-Stop, it would be a cabinet saw.

    Leave a comment:


  • Paul Ebert
    replied
    Thanks for the information, Ben. While I hadn't thought of the pulley being the problem, it had occurred to me to remove the belt as a way of isolating the problem to either before or after it. I'll give that a try. On the other hand, I really wouldn't mind having an excuse for upgrading.

    Leave a comment:


  • 1100xxben
    replied
    Paul,

    My father had a late 90s Craftsman contractor saw for several years before I moved out and started building my own shop. His saw started developing some weird noises when spooling up and shutting down and it ended up being that the bore of the pulley was SLIGHTLY larger than the motor shaft. The set screw had started working its way loose and it was essentially rocking back and forth. I tightened it up and it ran like a dream and was quiet as could be after that. Have you tried taking the belt off and firing up just the motor to see if the sound is coming from the motor? The saw blade/arbor should spin VERY freely and the bearings should be whisper quiet. Spinning it by hand, you could use a screwdriver as a poor-man's stethoscope to inspect the arbor bearings. Because of starter winding switches, motors can be more difficult to perform this kind of test.

    If it's not that simple... There really isn't much to the 1980s and newer Craftsman contractor saws. I had an 80s model for 10 years. When I first got it, I replaced the arbor and bearings, cleaned everything up and never really had another mechanical issue with it. I purchased a 90s model later, replaced the motor bearings, and that runs as smooth and quiet as can be. Essentially, the only mechanical spinning parts are the motor, arbor, associated bearings, and pulleys. If the trunion assembly is solid and consistent, you have everything aligned, and you have no interference with anything, there's really not much to go wrong with them.

    All that said, I scored a really good deal on a 1940s Unisaw ($75). I replaced the arbor bearings and gave the whole thing a strip down, new paint job, and fresh lubrication on all the trunion parts and it runs like an absolute dream. I built my own Biesemeyer style fence so I can rip 50" wide and now I don't understand how I ever survived without a cabinet saw . If you can't find as good of a deal as I did and you don't want to drop the money on a cabinet saw, you can still get a lot of good use out of a well tuned contractor saw.

    -Ben

    Leave a comment:


  • s7horton
    replied
    Everyone has their preferences. I just replaced my 13 year old Delta Unisaw with a powermatic. So many people told me to get a saw stop. While accidents are never planned, most are preventable with knowledge and focus. I wanted the quality of the powermatic. So I pulled the trigger. I can’t imagine owning anything but a cabinet saw. Both powermatic and sawstop are good machines.

    Leave a comment:

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