Is this going to kill me? What is the limit. Custom unisaw gang saw arbor addition

[tom suica]

Is this gonna kill someone by snapping an arbor? I'm dealing with a unisaw. Yes yes I know put a 10 hp unit on the unisaw and it will work fine! but no seriously. If anyone with the capability of making 1 of these decides to make 1 I want 1 too Paying customer.


I would like to make this arbor so that folks can cut multiple strips with a table saw and a power feed for stuff like cedar strip canoes and paint stirrer's and tomato stakes you name it.

as it stands you cant even put 3 blades spaced 3/8`ts

Anyone got any insight? 321062

[Davis Young]

Delta at one time had spacers for the arbor to mount two saw blades. From their 2001 Workshop Machinery Catalog, p.33: "No. 34-171 Spacer Collars, Set of two: 1/4" and 3/8" widths with 5/8" arbor hole. For spacing-saw blades to cut tenons in one pass." I'm not sure about three blades but you could definitely do two.

[David Kumm]

321064Here is the extension arbor I made for an old Whitney 77. My concern would be the stress on the relatively light build of the Unisaw type machine. The old commercial saws that had dado capability of 2" or multiple gang blades used a much larger stub arbor with an extension that was interchangeable. The arbor and housing assembly were many times heavier than on the light duty 10" saws. Bearings were large 6300 series with the ability to handle the increased radial stress. If you want to convert a regular saw to something that can cut multiple strips with a feeder, start with a big old saw, at least the Delta 12-14 but even better and old cast iron saw with a stub arbor. Dave

[tom suica]

Looks like I should have waited and gotten a tannewitz. http://i.ebayimg.com/00/s/MTIwMFgxNjAw/z/uIEAAOxyY3ZRp74-/$T2eC16FHJH%21FFl-s3IB4BRp74-LiSQ%7E%7E60_35.JPG Is an extended tannetiz arbor 1 1/8 inch diameter about 5.5 inches long for gang stack. Looks a lot like your arbor stub nut

[David Kumm]

Tannewitz used the same system as did some others. A few used the regular arbor with a hollow sleeve that threaded over it. Usually ended up with a diameter of 1.5-1.75". Dave

[J.R. Rutter]

After using a serious rip saw, I don't think i could go back to a table saw based solution. But I see the appeal of an accessory like this.

[Frederick Skelly]

My "gut" says this is a dangerous idea on a non-industrial-grade machine, Tom. But I admit that's "gut", not experience or deep knowledge. Still, I think you're right to be cautious.
Fred

[Jeff Duncan]

It's not just the small diameter arbor you have to worry about, the bearings that support that arbor are pretty small. If you pull one out of a Unisaw and think about what your trying to do while holding the arbor in your hand…..I think you'll likely come to the same conclusions yourself;) So I agree with the others that trying to make a small saw do more than it was designed for is probably not the best route. Then again that logic hasn't stopped countless people from throwing 5 hp motors in Unisaws so they have a "heavier duty" machine:rolleyes:

good luck,
JeffD

[Bob Falk]

A Woodmaster might work (albeit slow), though not sure you can space the blades as close as 3/8".

[Ted Calver]

Since you are presumably cutting thin stock or just a couple of layers of thin stock, setting up your 'gang' using smaller diameter blades like 8" should reduce the arbor load and might be workable with the longer arbor?

[tom suica]

The wood master.. Ah yes, the standard gang saw blade cannot be set so close together. But there is a video on their website that talks about custom gang saw arbors and that they can make any gang spaced to any measurement Also if you have the wood master and a metal lathe and some machining skill you should be good to make some spacers/ bore your own blades whatever... http://www.woodmastertools.com/features_benefits watch the iveo and at 2:41 he talks about how they customize arbors. Also you can clearly see their gang saw system is adjustable for a wide cut only without making your own or buying more tooling from them. I recently looked at a woodmaster but it was an early model.
I specifically purchased some blades like so for what i thought was like 4 or 5$ each 321077
Go read the description "http://www.ebay.com/itm/191655030986?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT" description states 3 and the guy is like its only for 1. Quote: "Sorry for the error. This is for only 1 . I can send you a refund of $3.00. Or you can send it back for full refund including the return shipping cost."


I replied with lolol good one. I know you are joking since the description states "This is for 3 (THREE) 7-1/4" CIRCULAR SAW BLADES HIGH-DENSITY CARBIDE TOOTH 24T. NEW NEVER BEEN USED.:" I will be looking out for the other 2!! thanks for following through on your promises.




Ted: I wood be doing both. Sometimes I have to cut 3/4 strips off a 3/4 board to make the "lincoln" logs for christmas i am too cheap to buy poison wood coatings from toysarethem my family muwahahahahahahahaha. They will never know my cheapness Spend 3000$ on machines to make 200 dollars of Christmas presents with!! Sometimes i want to cut a 2x4 into thin strips THROUGH the inch and half side.

[tom suica]

My "gut" says this is a dangerous idea on a non-industrial-grade machine, Tom. But I admit that's "gut", not experience or deep knowledge. Still, I think you're right to be cautious.
Fred

Fred I said I was thinking about putting this on a unisaw... How much more industr......... lolololol.


David Kumm I am very interested on my next saw being like this would you let me know of the table saws that have such systems? So i can make a small list of possible next saws also anyone else the knows who used stub arbor with addition. (http://www.sawmillcreek.org/member.php?74820-David-Kumm)

[Pat Barry]

Are you planning to gang up a bunch of riving knifes to match? I think some wood is going to be a real bear to rip with this type of ganged cutter and would be prone to causing huge kickback concerns

[Frederick Skelly]

My "gut" says this is a dangerous idea on a non-industrial-grade machine, Tom. But I admit that's "gut", not experience or deep knowledge. Still, I think you're right to be cautious.
Fred

Fred I said I was thinking about putting this on a unisaw... How much more industr......... lolololol.


David Kumm I am very interested on my next saw being like this would you let me know of the table saws that have such systems? So i can make a small list of possible next saws also anyone else the knows who used stub arbor with addition. (http://www.sawmillcreek.org/member.php?74820-David-Kumm)

Yup, Unisaw. I read that, thanks. I still wouldn't do it, considering the momentum of 3 spinning 7+ inch blades, running on a machine designed for one blade or maybe two (with the right manufacturer- tested parts).

But that's ok friend. I hope you find a safe way to accomplish what you're trying to do.

Regards,
Fred

[Mike Heidrick]

Big shaper w/ feeder and outeed fence with splitters an idea?

[Mike Schuch]

Setting up your unisaw with ganged blades to use yoursel.... its your body parts you are gambeling.
Setting up your unisaw with ganged blades for customers to use... that is just pure foolishness.

Look for a used Woodmaster, Belsaw, Hawk planer that have an optional gangsaw attachment. It would be much safer than your plan and probably cost the same or less since the powerfeeder is built in.

[ian maybury]

Hard to know where the limits fall Tom, and i have no hands on experience of a set up like that. I wouldn't to go there though.

One big problem is the possibility of 'whirling'. An overhung cantilevered rotating shaft (where one end is unsupported) is inherently unstable. Something (as in a cutting and/or out of balance force) pushes againt the unsupported end, causing it to deflect off centre. Which causes an increased out of balance force, so it deflects more, which causes and increased out of balance force, which causes it to deflect even more… Next thing there's a moment of vibration and it goes flying past your ear. (if you are lucky)

Any cantilevered shaft set up must ensure that this whirling never gets going.

It has to be well balanced, precisely centred, and run a stub shaft/arbour and bearing set that's of large enough diameter and of strong enough material to resist those forces it may encounter. Having a bearing fail badly could lead to catastrophe too, as it would permit whirling. Increasing the RPM beyond that designed for must eventually lead to problems. When the RPM is doubled the out of balance force quadruples - it's described by a square law.

The spacing collars and the add-on in the drawing seems at first sight very chunky. While the spacers in fact do contribute to stiffness, they just pass the load along to the mounting bolt/shaft/stud in at the root, and up the ante in terms of the rotating mass/effect of any less than perfect centring. The problem is that the arbour stud on a light duty saw is not designed to do this job - it's tiny, and intended only to apply a clamping force to single blade or dado already located on a stepped shaft. Not only that, any whirling force out at the end of a cantilever will result in potentially leveraged bending and 'pull out' forces applied to it on top of the tightening tension.

The stud likely would likely cause another problem too. Threads have quite a bit of clearance, and so they don't give reliable centring. This requires an accurately machined step or spigot...

[Keith Weber]

You put a 10hp motor on a Unisaw, and now you want to extend the 5/8" arbor and run 3 spaced blades on it? Reminds me of those tractor pulls that I used to go as a kid where somebody mounts multiple engines on a tractor frame to get more hp. Their run usually ended with a loud bang and a spectacular show of metal parts flying off in all directions. Yes, a Unisaw is "heavy duty" when you compare it to anything bought at Home Depot, but there are machines made for this that make the Unisaw look like a toy. That said, it's your toy.