Would lightening clamp/arm make any difference?

[LessPaul]

I am rebuilding a 1989 Shopsmith scroll saw, including, but not limited to all new new bearings, bushings, and general tweaking to make it the best it can be. When this saw was new it had blade clamps that had to be removed and a jig for alignment, thus it has a quick-release pin and spring mechanism. This saw has been upgraded to toolless clamps. So the long pin, the spring, and even the circled portion of the arm casting are no longer needed and could be removed and replaced with a simple roll pin. (As was done by Shopsmith in later versions of this saw.)

I've read how lighter clamps can reduce vibration and it got me wondering if there would be any advantage to lightening the arms on this saw. I suspect not, since the arms are over 25" long (counting internal pivot mechanism) and the % change would be trivial, unlike on mor modern saws with short articulating arms where a few ounces would be a bigger deal. But I thought it worth asking anyhow.

Anyone have experience in this sort of thing?

[WayneMahler]

I'm not familiar with this saw or the whole shopsmith machine. I'm thinking that since the saw was designed this way and later modified by the manufacturer that they may have made other changes to compensate for changing the blade holder. 25 inches of arm is pretty long and the further out you travel from the pivot point the more the weight ratio would change. May not notice anything immediately but you could add a balance issue . That would add more vibration.  

[OCtoolguy]

I ask this question purely out of curiosity. Why are you doing this? Is it just a project and you want to work on it or are you chasing a scroll saw? If it's for any other reason than purely out of the fascination with rebuilding an old saw, why not just get yourself a more up to date scroll saw? Please don't misunderstand my asking. I'm just wondering. I have been down this trail myself with an old Delta saw that I bought and quickly realized that even if I restored it to it's original condition, it was still an old saw and not anywhere near as good as a used Dewalt.

 

 

[rash_powder]

I was having horrible vibration problems on my Hegner until I figured out it was my bench.

In my attempts to fix the vibrations, I tried stick-on tire weights from Harbor Freight on the saws upper arm, to the rear of the pivot.  I don't recall how many I used anymore, but it was in my belief a lot.  It did not help at all, but oddly did not worsen things either.  

I talked with some of the engineers at work, and they said that the static balance is completely different than the dynamic balance.  They said that it was some pretty complex math.  

My problems were caused by flex in the bench.  Once I built a new, heavier, super rigid bench, it runs like glass.  Maybe make sure that whatever you have it attached to is not teetering on three of four legs, and the table/bench top is not flexing.  Maybe stack weights on the bench too - I had over 100lbs extra piled on to try and fix mine.  Also be sure the fasteners are snugged up good and not loose.  Another option may be to put a piece of rubber mat under the saw to absorb some vibration.  Last ditch would be to bolt the entire bench to the floor; but I would guess for most that is unfeaseable/unacceptable.  

Best of luck!

[LessPaul]

All, 
Thanks for your input. 
I neglected to say that I do not have what I would consider excessive vibration. I really need to stop using my phone in forums. I hate typing on it and I end up with overly abbreviated postings.
I have read that a popular modification to saws is the Pegas blade clamps.  The Pegas weighs less than stock, and some report lower vibration after the upgrade. For example the Scroll Saw Village post linked below. 
Removing the functionally unnecessary mass from my saw would be the weight/balance equivalent of installing Pegas clamps on a modern saw. 
But the issue is this:
-- The modern scroll saw has evolved to using shorter, low-mass articulating arms where the blade clamps mount. Upgrading to lower weight clamps has a significant impact on the mass of these arms. A side effect is, reportedly, less vibration.
-- My 20" scroll saw has long cast aluminum arms -- the twenty inches that are exposed, about another inch inside the machine to the attachment/pivot point, and another 4 or 5 inches as cantilever and parallel linkage.  I would not expect to notice detectable or measurable change in saw performance removing a few ounces of that mass.  I wondered if those with tool design or modification experience concurred. 
 

On 3/24/2021 at 10:34 PM, octoolguy said:

I ask this question purely out of curiosity. Why are you doing this? Is it just a project and you want to work on it or are you chasing a scroll saw? 

  Short answer, this is my version of fun. Taking an old machine, bringing it back to life, and making it like new -- followed by putting it back to work. I am a retired engineer and have a fully equipped woodshop in which most of my major power tools are restorations. As far as the scroll saw -- it was not a conscious purchase.  When I bought my 12" planer, the seller "threw in" the scroll saw. I've made little use of it -- basically using it as a handy "cut this in half quick" tool and something for kids to use. I recently decided to bring it back to life and see how I feel about "real" scroll sawing. It is now -- IMHO -- better than the day it shipped new from the factory. This is in part due to 3d printed nylon bushings that help stabilize the arms, thus overcoming a minor design flaw.  

Does it have the elegance and butter-smooth operation of a modern saw or features like tilting head, lift-up arm , or up-front tension controls? No. But I am certain it is a capable tool, more limited by my lack of skill than its lack of refinement. 

I have a sampler of quality blades on order from Bear Woods, and I intend on seeing what I can do with this fellow. If it kindles an deeper interest in scroll sawing, I'll buy a better saw. If not, no worry, as I enjoy the process of tool restoration and other than my time, have less invested in this machine than the cost of dinner out with my wife.   

 

Edited March 26, 2021 by LessPaul
clarity