Silver Mfg 36 inch Bandsaw
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  1. #1
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    Default Silver Mfg 36 inch Bandsaw

    It's been a very long time since I've been active on PM, so hopefully I won't be in violation of any rules (which I have reviewed).

    I have been gifted a 1924 Silver Mfg 36 inch bandsaw, purchased new by Mathis Yachts of Camden NJ, later renamed Trumpy which moved to Gloucester NJ, and ultimately to Annapolis MD where they closed up shop in 1974. It was sold to an employee and subsequently my father bought it and recently gave it to me. As it is not a Ships Saw it was relegated to cabinetry I suspect, and probably helped 'build' all the big Trumpys.

    My father did a near complete restoration of the saw but never had it under power. It came with the original (or at least 100% period correct) Westinghouse induction motor. I now have the motor restored and powered up, along with the saw drive wheel, which brings me to a point that I am not accustomed to - not sure what to do next. I'm able to pretty much figure out anything, but aligning the wheel shaft babbitt bearing blocks is not a task I've ever encountered before. I have some ideas, but I am hoping someone can provide some guidance.

    The horizontal adjustment is likely done with shims, but the axial alignment has 4 setscrews, 2 on end end, and lots of range. The upper wheel looks to be minimally adjustable, although I have not opened anything up to confirm, yet. The motor is attached to a matching adjustable mounting plate, which along with the saw is attached to a massive wooden base. There is no axial adjustment of the motor, other than the play in the 4 bolts. It was used for decades this way before my father got it, so I assume it was properly aligned back then. There are 2 threaded castings on the mount under the motor which appear to be used to prevent the motor from racking when under tension, however the hardware to attach to the motor is missing.

    As it sat when I test powered it, the new 4" flat belt drifts off the pulleys clearly indicating basic 'line shaft' type alignment is off. With no ability to change the motor alignment, more than maybe 1 degree, I suspect the wheel shaft alignment is off from the restoration work. I centered the bearing block in it's range and the belt only drifts a little now. A straightedge across the drive wheel pulley roughly aligns with where I would expect it to on the motor pulley.

    I've spent lots of quality time on the Vintage Machinery website (going back easily a decade for other machines I've worked on), but I was not successful in finding anything on this kind of alignment. The internet was even less helpful with a gazillion bandsaw alignment hits, none of which address bearing block alignment.

    Hopefully someone here has, been there, done that, and willing to share! Thanks!

    I will add a few pics later. I can't seem to find any that I have, which includes lying it on its side, using a 1947 marine chrysler straight eight as ballast. That's a whole other saga.

    John

    Next project up - Royersford Excelsior 21" camelback drill, age unknown. And helping a friend pour new babbitt bearings in an American Machinery 16" Buzz Planer.

  2. #2
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    Yes, I have aligned bearing blocks on heavy woodworking machines with shims or other methods of re-alignment, including making the mounting holes in the frame oblong, if the whole block is movable. For some small adjustments where i either can't or don't want to move/adjust holes, i have turned the shanks of bolts or created reduced shank studs, so the existing hole can shift against the undersize shank.

    The above assumes the Babbitt has already been fully re-scraped and aligned in the block => current state of bearings is "perfect".

    If you have to pour, resleeve, or even remove some shims and re-scrape, moving the blocks around is a dumb idea before those basic tasks are completed.
    Even though it is usually more work/material intensive, scraping (or boring) bearings should always be biased toward better alignment.

    For any more specific advice, pictures are necessary.

    smt, formerly from northern MD.

  3. #3
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    SMT,
    Thanks for the reply. It seems my picture management is beyond a fail, I can't find a single picture that I'd taken in the past. But I do have some new ones, and spent some quality time with it this afternoon.

    In that this machine has a single bearing assembly, which as I noted axially aligns the powered (lower) wheel, moving them is neither dumb nor a problem, but rather just premature. Adjusting them simply rotates the entire shaft in respect to the upper wheel. I attached weighted strings at the "10 and 2" positions on the upper wheel and readjusted the bearing alignment screws for an equal gap on the lower wheel. It ended up pretty much back in the original position, which was only arbitrary anyway from the restoration work in the past.

    I then went about trying to establish if the motor is in fact true to the machine, and it turns out it is not. I had dinner with my father last night and found that he built the heavy wooden base, not the previous owner that had used it for ages. Even though the motor mount was parallel to the saw base it looks to be off at least a couple degrees. You can see in the attached pic that there is about 1/4 inch offset over 18 inches, with the motor and base forced as far as possible with the current mounting holes. Before I thought to check that I removed all but 1 screw and used clamps to force some rotation of the motor. As the clamping forces were only marginal, the belt slipped badly as it spun up the wheel, and skidded the opposite way until the slip stopped, then wandered off to the left as it has been doing. I moved it some more, and it still insisted on moving to the left, just not quite as far. That's when I decided it was time to check the motor shaft for parallel to the saw shaft, and found the still large error.

    I also looked at the crown on the motor pulley, which appears to be the original paper pulley. It looks like it has worn in such a way that the outer (left) edge is larger than the right edge, and likely the reason it insists on drifting left. The peak of the crown is clearly off center to the left. My first thought was to put it on a 1.25 shaft in my SB9 lathe, and try truing it up, but I'm not sure I'm good enough to do that. My second thought, which I'm still mulling over, is to put it back on the motor (after aligning it properly with the saw) and using my belt sander and some sort of stops to dress the entire surface back to a proper crown. The cast iron saw pully is also crowned, but with a "V" shape, not a radius.

    The upper wheel is fixed in a pair of non-adjustable "V" ways, and has only the standard blade tracking adjustment. As long as I have the lower shaft bearing block set right, putting the 2 wheels parallel with each other, there is no other built in adjustment. I will need an 8 foot straight edge to verify if they are parallel, and not offset top to bottom. That's where any shims might come into play under the bearing blocks.

    I'm going to be out of town for several days this week, but hopefully I might get some more time to work on it.

    It does look like there was 1 alteration made to the machine. In some pictures I found on Vintage Machinery, and in a catalog there, it looks like the lower blade guide was replaced with the same type as the top, which may not be original either, but could be. It looks like the lower one was originally a pair of blocks in a "V" shape. An additional hole was drilled through the casting for a grease fitting access on the opposite side, and the guide mounted on a custom shaft/cam assembly into the original hole. There is an unused threaded hole that could match up with a bolt in the original design. I would assume that Mathis/Trumpy would have done this a very long time ago. As I noted, both guides are identical, and very old I'm sure. They are from Black Diamond Saw and Machine Works, of Nantick Mass. It seems they are sort of still around. An ad from 1901 looks almost Identical to mine. It's possible they are OEM now that I've looked deeper into them.

    John
    Attached Thumbnails Attached Thumbnails bearingadjust.jpg   bearingmount.jpg   motoroffset.jpg   saw.jpg   saw2.jpg  


  4. #4
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    I've crowned both paper & steel flat belt pulleys up to about a foot diameter x 3" or 4" wide, with beltsanders or angle grinders.
    It can be done by eye, and don't over-do the crown. Aligned belts really don't need much, if any crown. Use 60, or 80 grit minimum.

    When using a hand-held abrasive machine, the big factor is to not create a situation where it bounces. Hold it steady against a shin or knee with arms braced, and let the wheel kiss it. Adjust until the dress is constant. But you can't ever relax and let the abrasive "rest" on the turning pulley. Also, the angle should be across the face; and perhaps alternate which way across the face from time to time. If the bearings are decent & there is not too much inertia, in some situations you can give the wheel a spin, & keep it spinning & control the speed with the cross-face angle alone. (unpowered)

    I think Black Diamond parts are still available.

    I'm not a fan of Vee form dress on bandsaw wheels becuase i sometimes use bands as wide as 1-1/4". I do not believe the V-form gives ideal support to bands over 1/2" wide. That was popularized by a guy who posts on OWWM and even wrote some FWW articles extoling it. It works for narrow bands (1/2" & under. Or maybe (reading the articles of the time) he just didn't know how to dress wheels by eye and abrasive.

    Again, a good wheel should not be concave. Which implies some crown. However, for wide faced wheels, the amount necessary is "not much". A good bit of the effect of proper dressing is to make the wheels round so the band does not throb.

    Good luck!
    smt

  5. #5
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    smt,
    Thanks again.

    The flat belt wheel on the powered shaft has the V crown (18" dia, 4.5" wide). The original specs indicate it was a 12" pulley, but was probably changed to match the motor & pulley. That size was from a catalog 14 years earlier, and unchanged from one 5 years older yet. The main shaft was also replaced as I believe that's where the serial number would have been. The mid 20's seems to be a mixed period between line shafts and motors, so I've read.

    The band wheels are both flat, currently. It only makes sense to replace the tires as they are not in great shape. The upper wheel is badly out of balance, and rebalancing is in order after new tires anyway. I tried sticking large washers on it, but couldn't make a difference until I put a 3/8x6 bolt with 2 nuts on it, then it was getting close. I suspect there may be a weight missing, although there is no indication of it anywhere. There are also no drilled holes from balancing when it was built. The bottom won't spin freely enough to judge currently. The babbitt bearings on the bottom were fitted with grease fitting but I'm going back to adjustable/on-off oilers. Hopefully then it will spin more freely, or that and some shims. It could simply be too tight. Worst case I could remove the bearing caps and see how it responds. I need to take them off to clean the grease out anyway. I'm hesitant to remove the wheel & pulley so allow removing the shaft. The wheel hub has seen better days, but it runs true.
    I might try the dial indication method while it's spinning, but I'm not sure how much a 1300 lb machine will move.

    My thought on the paper pulley is this - Align the motor shaft parallel to the drive pulley first, then set up a fixed parallel to the shaft just far enough out to clear the pulley, then put it back on so that I can directly watch the change as I dress it. I'll set up a support for the flat side of my belt sander, and as you noted brace it and gently rock it back and forth. I probably will have to do the middle and right extra, as the left side is over a 1/16 already.

    John


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