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View Full Version : My FANTASY bandsaw utterly demented!



Van Huskey
05-15-2012, 12:33 AM
As some of you may know I kinda like bandsaws. Something interesting happened last week (I started writing this over a month ago so it has been longer than a week!), I was working in my garage when my mailman pulled up to drop off a package. It turns out he is a retired woodworker and he spent 20 minutes or so looking at my saws and talking about them. Italian saws were new to him and as I described what made them “special” he ended up with the comment “Sounds like the perfect bandsaw”. My immediate thought was they aren’t really close to perfect but didn’t say anything since even through there was no rain or sleet involved I figured bandsaws shouldn’t keep him from his appointed rounds either! This has had me thinking what would be the perfect bandsaw and I came up with roughly my set of criteria. No company makes or has made this perfect, for me, saw AFAIK. Finishing the post was spurred on by a recent post that ask me about my favorite or best bandsaws. So here are my thoughts, understand even though it has been sitting in my computer for a while now and I have given it a good deal of thought I didn’t spend very much time actually writing it so hopefully it will be intelligible! It also hit me in writing the thread that it will be helpful in some spots to give specifications for this “perfect” saw so I had to consider the overall size/capacity, so I decided on a saw with 24” wheels and 24” of resaw so any specs I give will be considering this size and can be mentally scaled proportionally if one so chooses.

FRAME

The first attribute would be the frame/spine. Many bandsaw fans would say this is simple, gotta be cast iron! Not me. CI has great vibration absorption and back in the day when high manufacturing tolerances were expensive or unobtainable I would agree, this however is the modern world. I am more than happy with a welded steel bandsaw when built to the heavy spine standards of the Italians especially Centauro. When all the reciprocating parts are balanced really well and vibration considered in every aspect of design there should be little if any significant vibration to dampen. Once you get up to the well built weight of quality mid-sized saws you aren’t going to push them over or slide them around so the extra mass of CI is a non-issue as well. The production and shipping cost of the extra mass becomes huge and there isn’t any true benefit IMHO.
So, build my saw well and give me a steel frame, unless you want to built it from CI AND sell it and ship it to me for steel prices…
This would make “my” saw about 1,600 or so pounds equipped in the manner I will detail.

MOTOR

Next up is the motor and drive. I am not remotely a metal worker so I have no desire for a high reduction complicated drive system but oddly enough I do want a level of speed control. Having used different saws with blade rates from 3,000 to 7,000 sfpm + I have learned that sometimes it is favorable to adjust speed even when “only” sawing wood. My saw would have variable speed from about 3,500 to about 6,500 sfpm accomplished via VFD (variable frequency drive) since the saw would need less HP at lower speeds I wouldn’t employ a belt systems but just use the VFD. I would equip this saw with a 7.5hp or 10hp 3 phase direct drive motor. Direct drive would reduce the vibration as well as parasitic losses. The motor would not be cheap, given my speed requirements it would be a 1200rpm motor. (OK I didn’t bother with the math so it may be a little off my 6,500 sfpm spec but a 900 rpm motor will be too slow). The VFD will allow a measure of braking (but not fast enough for me so there will be a mechanical brake as well) along with soft start which is important due to my wheel choice. My rule of thumb is 1hp per 4 inches of resaw for a saw that allows a good resaw blade to be the limiting factor, the motor is sized larger so it still meets this goal even when the speed is reduced, it won’t make it when running 3,500 sfpm but will be more than enough for the required reduced feed rate.
In short, big direct drive motor with VFD control.

 
WHEELS/TIRES

I have some interesting thoughts here which would send a production engineer into seizures and may be the one area which might not be feasible. First, is the very feasible. I want cast wheels, big, thick heavy cast wheels, on the order of 100 pounds each. This is well over the norm for even well built saws and I want them on even larger say 36” wheeled saws where steel is more the norm due to weight. I plan to get away with this by using the soft start via VFD. Hammering a saw with the start up inertia of huge cast wheels is bad for most everything in the saw from the motor to the operators delicate senses. By ramping up the speed via VFD this problem goes away and with the massive motor and huge inertia a constant speed and thus smooth cut are ensured.
Here is where things get tricky, I like flat tires for resawing. Full width support of wide resaw blades is important for reducing fatigue. BUT with narrow blades it is extremely nice to have a crown so they are easy to track. My wheel is very wide and has a front section that is flat and a rear section which is crowned, now I said the crown is in the wheel not the tire. It would allow tracking of blades up to 2” wide on the front section and at least ½” on the rear crowned portion. The front tire for the flat section would be thick rubber with a T profile for easy alignment and changing plus durability for dealing with the high tension of the resaw blades, the rear tire would be thinner urethane to mold to the crown. Given the high potential speed of the wheels both would probably have to be glued on, I hate it but probably true at least for the rear tires. The wheel bearings would also be oversized to handle the high loads with aplomb.
These wheels would be balanced to very high tolerances and have very good concentricity. Low vibration = good steel saw!

DOORS/CONTROL SURFACES

The door issue is fairly simple the doors would be one piece and have louvers near the top (explanation in dust control). They would open FULLY even with the supplied mobility kit AND have a detent when fully open to prevent unintended closure ala a car door. They would be supplied with a micro-switch in order to prevent the saw being turned on with the doors not fully locked down. They would be sealed all the way around again for dust control. They would have large knurled metal wheels that locked the doors tight as they rotated on a pin (similar to many bandsaws now). The doors would be heavy gauge steel, maybe even with a crease down the middle in order to prevent vibration and noise. The center section between the top and bottom would be beefed up so when opened they felt like one solid door, not two parts connected by spaghetti. While we are at it the whole saw would be prepped well for power coat and have a smooth finish in colors and graphics that make you smile and want to use the saw, not colors that make one feel like they landed in a 1950’s asylum.
The warning stickers would be tastefully done and group together as much as possible. They would be produced using a glue that allows them to be as permanent as OSHA requires but as easy as possible to remove cleanly for the hobbyist that hates a cluttered view.
All the control surfaces would be heavy and chromed. Finely knurled where need be and polished smooth where not. The VFD and switches would be integrated into the spine so they would be flush except for the switches and speed pot. Both the VFD and magnetic switch would be branded with the saws manufacturer and not look like a collection of surplus parts.

TENSIONING/TRACKING

Tensioning would be accomplished via a large chromed (but textured for good bite on the hand) wheel attached to a large acme screw. The would be no quick release. The tension meter would be attached to a load cell with a digital display which reads in absolute pressure as well as a small key pad to enter blade width and gauge so a second line would show strain on the blade in PSI, making correct tension easy peasy, and repeatable. The spring would be massive and capable of tensioning a 2” x .042” blade to 35,000 PSI without bottoming out. The load cell would be connected to the motor control and not allow the saw to be turned on if tension was below a certain level, preventing tension off starts and stopping the saw automatically if the blade breaks.
Tracking would also have a large easy to turn wheel with a tracking window and an LED light inside the frame to illuminate the blade/tires. The motor control would have a “tracking” speed button which would spin the wheels under power but at a reduced speed of about 100 rpm to make tracking painless. The tires would be a light color to ensure it was clear exactly where the blade is tracking.

TABLE/TRUNNIONS

The table would be large, on the order of 32x40 and tilt from 48 to -10 degrees. It would be massively heavy and deeply ribbed, solid enough NOT to need a pin BUT a pin would be included. All the areas where feeder and feeder fences would be drilled and attached would be beefed up and careful design of the ribs would be undertaken to make sure there would be no issues with attachment nor loss of integrity.
The blade slot would be out to the right and though not ideal but probably needed for the particular fence. The throat opening would be large and easy to move a 2” blade in without damage. The throat plate would be large and made from brass and have sacrificial inserts for a ZCI both flat and for tilted cuts. It would have leveling screws.
The trunnions would be oversized and cast iron, it would have a large scale with positive stops at standard angles, there would be a built in digital inclinometer as well. The table would be adjustable as referenced to the blade, allowing drift to be cancelled by the table and making the DUAL miter slots useful. The table edges would be drilled and tapped for easy additions of Aigner extensions, if the table size was inadequate for a job. The table would have a large rack and pinion adjustment arm (ala Grizzly oh my) with a positive lock to increase table stability even though it should not be needed.
The blade guard would be a quick release swing out design to allow quick and easy access for blade changing and be equipped with a positive catch and safety micro-switch.

GUIDE POST

The guidepost should be square heavy and very rigid. It should have a smooth adjustment with a large hand wheel and be adjustable for parallel/perpendicular in two planes as well as friction. It should have a cover over the top of the frame so it is covered when fully up. As an option a electric guidepost control could be added.

GUIDES

First and foremost the guides should be easy to adjust. Both above and below the table large hands should be able to easily access the controls. All adjustments should be accomplished without tools and the knobs should be shaped for easy tightening and the screws on the knobs should be precision threaded and specified to allow for good torque without damage. The guides under the table should be height adjustable so that the lower guide can be just below the table at all angles. It should be on a precision track so it is easy to adjust and to make allowances for being parallel to the blade.
The main guides themselves would be ceramic, similar to those found on Laguna but with micro-adjustments and larger ceramic surfaces with the thrust surface also being split in to two with a wide separation like the side guides on the Laguna guides. They should attach to the guide post with a square mount which is screwed into the post. It should have a provision for quick change to a grooved thrust bearing ala the Carter Stabilizer and provisions for a quick change to a Cool Block type guide as well. All of the guide mounting options should have an indexing key to facilitate quick alignment. There should be adequate adjustment to ensure all blade widths can be easy and correctly adjusted for.

ELECTRICAL

As I have mentioned in earlier sections there is a lot of electrical and electronic things going on with this saw. It will have multiple readouts as well as a VFD for motor control. The magnetic switch will have a large off paddle and require reset. There are several micro-switches as mentioned to prevent unsafe operation. The internal wiring will be high quality and the ampacity of the internal wiring will exceed the minimal, I hate seeing a machine with uber-skinny wires, I know they are short runs but still.
On the back side situated beside the motor (for form factor) would be a positive lockable disconnect which would have a breaker for current control. It would come with a high quality 15 foot cord with the proper NEMA locking plug AND the matching locking receptacle so as long as the wiring in the wall was correct you would have a proper high quality setup without going to the store.

BRAKE

Along with the electrical brake there would be a footbrake with micro-switch connected to a serious (think small car drum brake) mechanical brake. The foot pedal would have significant mechanical advantage built in for a quick stress free stop. The pedal would have a quality non-slip surface.
This highly effective brake would require another bit of complexity. There would be a limit mechanism hooked to the brake pedal what would allow the micro-switch to trip BUT not allow the mechanical brake to engage, this limit would be engaged when narrow blades were used since engaging this brake with a narrow blade would rip it right off the wheels. This limit switches position would be run through a logic switch connected to the tension meter that would not allow the saw to be turned on if the full brake were engaged and tension was below a certain amount (based on the assumption the low tension meant a narrow blade was installed) and conversely would not allow the saw to be turned on with the brake limit rod ON preventing the full brake from being used if the tension was above a certain level (assuming a wide blade that would allow mechanical brake usage). The electric brake would be set to allow quicker coast down but not a rapid stop so it would function with any blade.

BASE
The base will have integrated casters what can be raised and lowered via a hydraulic foot pedal. It will raise enough to roll effectively over the average (read not perfectly flat) concrete floor and have large diameter wheels to roll well over small imperfections.
One of my pet peeves about trying to have one saw do everything is the table height. For resawing particularly tall cuts one needs a low base, maybe in the 34-35” range to control the material properly. When contour cutting it is much easier to work the material if the table is higher, say 43-44” above the floor. So my saw has a built in scissor lift which leaves the table at 35” when down and can raise it to 44” when fully raised. It will be designed to accommodate several hundred pounds of ballast in the protion of the base that does not move, allowing the owner to reduce the raised center of gravity at their discretion. The base of the saw would be extended in the rear (not past the table) to make sure their was a very wide stable base with or without ballast.
DUST CONTROL

As mentioned the top and bottom cabinets would be sealed as well as possible. There would be the standard chamber right below the table with a sacrificial ZCI and a 6” DC port the chamber would be sealed as well as possible except for a properly sized vent at the top opposite of the hose fitting. And work in conjunction with the perforations in the brass throat plate. There would also be a 6” DC port at the bottom of the lower cabinet with angled dust trays to direct the dust to this port. There would be louvers near the top center of the lower door to properly direct the airflow. There would of course be a tire brush for the lower tire.

FENCE

The fence would be a modified version of the Laguna Driftmaster. First its size would be increased to allow it to move fully from against the spine to the blade. It would have the same quick adjustment along with the fine adjustment BUT also have a system for locking securely on the back side as well. It would have the same excellent drift adjustment (although this saw has a table adjustment the fence could be used for tiny and or quick adjustments when miter slot parallelism was a non-issue). It would have a short high-low fence with the tall portion being about 6 inches. It would have a separate 12” tall resaw fence with front and rear stabilizer arms that attached to the back of the fence to create a very rigid fence. The fence would be equipped with a digital readout with multiple functions for use with repeated cuts and resawing activities. The fence would be designed to take a version of the Laguna/Co-Matic “belt sander” feeder.

OTHER

A couple of small items. There would be a good work area lighting system probably best accomplished via multiple LEDs. I would like to see a multiple position laser for guiding work. It would cast a long thin line back toward the user for off hand resawing and a bright point very close to the blade teeth for following contour cut lines. I would also like to see an adjustable blower to clear dust from the cut lines.
Finally, I would like a sensor that could “see” me arrive and leave. When I arrive the saws main power would be turned on (unless the lockout was engaged) and it would say hello in a nice sultry voice, then turn off the main power when I left the shop telling me goodbye and have a nice day and reminding me to return soon.



 
Wow, this turned out to be a treatise! Originally, I didn’t think it would be but a couple of paragraphs. Even now I am sure I missed a lot of areas that would need to be addressed were this even a glimmer in a product managers eye! In the intro I said no one had made this saw as far as I know, now after going nuts I KNOW it has not been built, nor is anything near it likely to be built for numerous reasons. Even at the economy of scale of the average 24x24 saw this over electronic controlled monster would probably cost… you know I don’t even have a guess but it would be expensive if it was reliable.
Feel free to add, subtract, disagree, laugh, puke or just tell me what couldn’t or wouldn’t be done. I had planned to entitle this my dream saw but I think that suggests something more in the realm of reality, this is a fantasy saw, from the mind of a truly demented man!

ian maybury
05-15-2012, 5:05 AM
That'd be my sort of list too Van - but it's perhaps a testament to how good the big Italian saws actually are in that if you then ask how much of the list is nice/incremental improvement, and how much is actually a must have/move you into new territory stuff there's maybe not that much that's a show stopper. There's not that much that's fundamentally determined by the initial design choices, and not possible as an upgrade either.

There's also the question of how much of it would be better added on to a single saw, and how much is more cheaply and conveniently obtained via a second smaller saw.

Another solution to the flat/crowned wheel thing might be a hollow urethane tyre filled with fluid and piped back to something similar to a very small hydraulic cylinder or diaphragm deal. (no moving parts) Flipping a lever would move the piston in the cylinder/the diaphragm forward and slightly inflate the tyre to create a crown, releasing it would return to flat. The whole lot could be very small and mounted on the wheel and counterbalanced so that it goes around with it - no need for rotating seals or anything.

Another 'improvement' might be something to eliminate the slight variability in tracking that tends to leave a band saw running a carbide blade a shade less precise/predictable than a table saw. Not sure what it might take, in that it depends on how many variable are in play in the end. Maybe precision blades (consistent tooth grind and precision jointing - a Lenox carbide is possibly there already) plus some sort of automatic sensing and adjustment of wheel tilt(s) to deliver consistent positioning of the band on the wheels might go a lot of the way to delivering this. A very strong chassis plus whatever it takes to run ukltra high blade tension (hydraulic tensioning/special blades?) might help too.

I guess what I'm saying is that even high end band saws tend to have some lack of precision built in, but that this may be as much a consequence of the traditional way of looking at them, and the traditionally relatively low price point as basic technical limitations. Some are happy to pay very big money for high end table saws with all sorts of electronic positioning and other gizmos built in. Wonder what you would end up with if you took a big band saw down this route?

Throat depth is a limitation, but on the other hand can be overcome with additional wheels. Depth of cut, curve cutting and its vertical nature are advantages. The length should lead to very long blade life. Might such a saw be the safer and more versatile alternative to the table saw?

ian

Erik Loza
05-15-2012, 9:01 AM
Van, that would be a really great bandsaw.

You mentioned it but one thing I have always wanted to do was fab up a little steel bracket and put a high-intensity LED right there, next to the upper guides. It could have a bungee cord-type power supply that would accomodate the telescoping of the guide post. Would not be difficult at all to do. Or, one of those little "light bars" with focused LED's, mounted to the bottom surface of the upper cabinet, pointing down at the work table.

Erik Loza
Minimax USA

David Kumm
05-15-2012, 10:24 AM
Van you actually need a 720 rpm DD motor to hit 6700 fpm with 36" wheels. A 10 hp 720 rpm motor will pull 35-40 amps at three phase. I guess I would go the opposite route. Cast iron frame with a little style. Base like a Y20, pancake motor as an integral part of the casting like Oliver, C frame just because they look cool. Cast aluminum doors and a lighter wheel. Easier on the spindle and bearing assembly and easier to injection brake. Matching saws in large and small. The guides on a resaw are kind of irrelevant but Hanchett or Wright look cool. Vfd built in but with a bypass switch to run directly when not needed or if the vfd craps out. I don't need any tension scale as it is easy to attach the Starrett but would like a dead on electronic tilt and rip fence scale. Running counter to all my wants is my appreciation for the simplicity of the machine and maybe I shouldn't screw it up with complications. Ferrari's are great but $20K for a 10,000 mile checkup takes the fun out. There is something to be said for two wheels and a blade that just spin. Dave

Ryan Hellmer
05-15-2012, 12:40 PM
I would think with a massive upper wheel you would risk stressing bands too much, especially on slow-down. It seems like we've come dangerously close to a perfect bandsaw on a number of occassions. Van, have you ever run a tannewitz? I'm thinking, other than the steel vs. cast iron, you'd find a lot of your attributes there. Coupled with a VFD, you could probably even slow them down without too much risk to the MASSIVE motors.

Interesting thoughts on the tires. It sounds like you advocate a 3" wide rim with flat up front and crown at the back? I like it. One potential issue with Ian's suggestion is that bandsaw wheels/tires are not loaded around their entire circumference. At high tension I would be concerned about "hydraulic" fluid sloshing around the wheel creating significant issues with balance, concentricity and consistency.

Someone should photoshop a frankensaw with all the parts from various manufacturers in one place to demonstrate the perfect saw. Until then I'll settle with my reasonably well-performing saws.

Ryan

glenn bradley
05-15-2012, 3:30 PM
This is great. Let's do one on a drill press ;-)

David Kumm
05-15-2012, 9:57 PM
Van, take a look at the Wadkin resaw on Woodweb. Wrong voltage but hits quite a few points. Dave

David Winer
05-16-2012, 8:44 AM
Your dreamy list of features leaves out a Users Manual and Maintenance Manual: both well written and illustrated. These volumes would be printed in easy to read type with color and bound for permanence.

John Shuk
05-16-2012, 9:07 AM
:rolleyes:Van is the only person I can imagine that has to think about sex to get his mind off of bandsaws...just saying.

Jeff Duncan
05-16-2012, 10:10 AM
In a thread like this anything goes, but.....I don't see the logic of using steel over cast iron to save on shipping costs and weight, when cost is disregarded in every other aspect of the build:confused:

I'm with David here, a nice old cast iron saw with a little 'flair' is a thing of beauty. And I think no matter what you do, you'll never get a perfect bandsaw. The ideal saw for curved work is always going to conflict somewhat with the ideal saw for re-saw work. So now you just need to have 2 perfect saws....back to work:D

JeffD

Van Huskey
05-16-2012, 2:29 PM
In a thread like this anything goes, but.....I don't see the logic of using steel over cast iron to save on shipping costs and weight, when cost is disregarded in every other aspect of the build:confused:

I'm with David here, a nice old cast iron saw with a little 'flair' is a thing of beauty. And I think no matter what you do, you'll never get a perfect bandsaw. The ideal saw for curved work is always going to conflict somewhat with the ideal saw for re-saw work. So now you just need to have 2 perfect saws....back to work:D

JeffD

Jeff I agree I did nale the choice of steel seem like it was based on cost, actually that section had been sitting in my computer in a Word document for over a month so the timbre of my thoughts had changed a lot. I suppose I would still defend the choice of steel for two reasons other than cost. First, though it may not appear that way everything I included was, at least in my view, there to make the saw more useful (except a couple of minor cosmetic things). I do not think that a large bandsaw weighing in at 3/4 of a ton needs cast for mass and I want it built in a way that it does not need it for vibration absorption. Second, I don't think welded steel saws need not to have "flair", last time I checked the body of a Ferrari 250 GTO was made of steel, further take a look at a Delta 28-350 it is welded steel but definately has Art Deco cues (which I love). My point being steel actually has more cosmetic potential if one wants to make the saw "pretty". Although it could be done making a graceful "C" frame from steel would be a task though. In the end I just like steel for some reason...

@ Ryan, having rethought the wheel mass issue I think it would be better to go with a more massive near solid lower wheel and a much lighter 30 pound or so upper cast or steel wheel. This allows more braking options with smaller bands.

Dave, the Wadkin is a very nice saw. I saw a new to me vertical resaw recently on the web that was VERY cool, meant to book mark it and send it to you but forgot. Unless all the pictures were reversed it was backwards with the spine on the operators right.


If I did this 10 more times the "saw" would be different each time it really is just a group of musings. One of my favorite bits is the load cell, Carter made a simple version for 14" Delta clones but I wish there was an off the shelf solution for my saws.

Jeff Duncan
05-16-2012, 9:51 PM
Hmmm, I have a thought just starting to come together......Van muses about the perfect bandsaw day after day. One day, after a beer or three, he goes over to his machinist neighbor and starts with "what if I bought some steel and....???"

I don't know when it's going to happen, but I'll stay tuned:D

JeffD

Van Huskey
05-16-2012, 10:02 PM
Danny is a great and accomodating guy but he doesn't suffer fools, idiots or madmen well. With a Rube Goldberg saw in me head and a few beers in me belly I would be all of those and then some.

Chris Parks
05-17-2012, 2:24 AM
Van, you could increase the mass of any wheel with add on machined "covers" attached to a wheel. However, slowing one wheel down and not the other if too heavy might cause band problems, just a guess mind you. It would not be too much of an issue to brake both wheels using a linkage through the spine to overcome this.

curtis rosche
05-17-2012, 2:54 AM
why not just say screw the bandsaw? i remember reading acticles from a few years back, about sawmills using lasers instead of a huge resaw. theres no limit on radius of cut, there is almost no loss to kerf, no tensioning, no sharpening, no need for a super huge machine, no wheels, no tires, no vfd.

i know lasers arent cheap, but the prices have come way down in the past few years and theyve gotten smaller

curtis rosche
05-17-2012, 2:56 AM
another plus to a laser, you can just any shape object, unlike on a bandsaw when your trying to cut a sphere or other shape without a flat side, cause theres nothing pulling the wood in any direction but you. and there would be no hand injuries like mine due to a dull blad in hard wood

Kent A Bathurst
05-17-2012, 9:01 AM
Add hot-dog sensing technology, and start your own company to build 'em.

curtis rosche
05-17-2012, 11:44 AM
Add hot-dog sensing technology, and start your own company to build 'em.

wanna jump in on this and make it a reality?

James White
05-17-2012, 11:59 AM
What would your saw look like if we came back into the realm of reality. Or in other words not a money be damned and more realistic saw.

Have you ever thought of calling the engineers at your favorite manufacture? I am sure the below options are quite practical and a real saw seller.

"Tracking would also have a large easy to turn wheel with a tracking window and an LED light inside the frame to illuminate the blade/tires. The motor control would have a “tracking” speed button which would spin the wheels under power but at a reduced speed of about 100 rpm to make tracking painless. The tires would be a light color to ensure it was clear exactly where the blade is tracking."

LED lights to illuminate the guides as well. Especially the under table guides.

James

Van Huskey
05-17-2012, 2:55 PM
Honestly, James I haven't thought about stripping the folly out to see what was left. Probably the thing I would be most excited about (that doesn't really exist) would be a load cell based tension gauge, not needing all the bells and whistles I added to it reading in absolute pressure would be fine for me.