So there is nothing better than an old machine to challenge one.
Over the weekend i ended up pulling my old scroll saw apart again.
Subsequent to the advice and comments i got here i did more digging around on the web and came across a comment that rung the bell.
This is all obvious if one stops to think.
The bearing on this machine is bronze self lubricating type that the main shaft goes up and down in.
These are pics of the shaft and upper bronze bearing.
Given age, and dependent in type of use, they are the problem child and wear.
There is also a bearing pressed in the casting for the bottom.
Bear in mind the whole chuck mechanism is a complete compromise in my view because to sell the machine for the widest use and in marketing terms have the most "features" and accessories they wanted to be able to have the jaws hold a variety of blades. So this machines jaws accept a real jig saw blade, a file type blade and then all the way down to a thin scroll saw blade.
Here is a pic of the lower jaw and its config. The blade inserted is a modified fret saw blade.(thick and wide with pins knocked off.) Used this to get something to cut but it allowed me to see the issues clearer.
The thing is the reality is if you do real scrolling you go mad very quickly on this machine with the existing jaws.
This jaw you can see will allow a real scroll blade to be able to be clamped and positioned anywhere across the 1/4" width.
Do the opposite at the upper jaw and you can very well have a blade leaning front to back by 1/2" angle.
Now take an old machine where it has been used in a factory with a real thick jig saw blade..(thats what the v groove is for this chuck rotates in the shaft to be able to present the v groove in the right orientation for the blade edge to be perpendicular to the operator) then that bronze bearing has experienced quiet the force and wear as the workpiece is pushed against it.
There was a attachment accessesory that rockwell /delta sold that was supposed to be installed for this purpose to act as blade guide and the small roller wheel on the blade guide above the fence was to be the "thrust" bearing equivalent to what we have on a bandsaw. This was part of the clue to the cause of the problem. This small roller "bearing" was worn beyond belief.
So add to the jaw misalignment potential
he aspect of not only worn shaft bearing but worn shaft and voila you have the jaw jumping anywhich way but loose (lol ) and the poor little scroll saw blade aint got a chance of survival.
Then the other clue was that the part attached to the shaft that is used to attach to the drive cam and make the shaft go up and down is connected via a pin. Pin is supposed to be press fitted to the rotating cam and run freely in the plastic ( i think derin) sliding guide that forms the transfer point kinda gearbox.
Well this pin was no longer fixed in its cam. So it on its own is rotating and wearing its own mounting hole causing a further bunch if trouble and vibration.
I can totally kick my own backside several times because when i first stopped to refurbish this machine i just did not apply enough grey matter of my own.
I ran forward on the basis that the machine was working and had been in use at this factory and so assumed ( make an ass out of me) that what the heck it was working with these issues so its fine right! WRONG.
So got my buddy over to confirm my thoughts, he is a master mechanic and retired and without me knowing he used to actually fix these machines. Dang should have called him even before i went to work on it.
Well the parts are not available from delta or the web and if one can find apiece they either outrageous price or worn old parts.
So managed to find bronze bearing that can be machined and my buddy had he discovered in his stash the lower one.
So then i looked around for a small local machine shop and (cue the heavenly music ) taaaa daaaa i am having the whole lot remanufactured and fix for $200 BUCKS.
This guy will be making
new pin and and rebore cam and fit it.
Machine new bronze bearing i found to fit.
New self designed lower and upper self centering quick fit chuck jaws
new collar to hold bearing more securely in lower mounting.
When done i will have a neat scroll saw and potentially after a little refinement i suspect a set of jaws i can get manufactured and offer to all the guys out there that wish to upgrade their saw to make it easier to not only setup a scroll saw blade in the machine but to also fix the blade back to the upper jaw when jumping from one hole to another on a workpiece. Right now with those clampy type jaws operating off an allen screw its a joke to do this.
Then i suspect this machine will be a nice s roll saw to have in my shop.
Given what i have into it at this stage it will have cost me around $260 in total thats including the previous new part i got off ebay.
Not bad if it gets close to the category of the new machines.
I hope this post helps anyone else with this machine just stop and check that theirs is not prone to some of the same wear.
NOTE. One thing i believe could have contributed to this machines wear and tear in the gearbox part was the issue of broken blade parts from the bottom of the blade ending up falling down through the bottom of the lower jaws and through the shaft (tube) and into the oil and gearbox.
The tube should have a cork plug in it to prevent this. Inmho the jaws should or could have had this plug right up top but hey this is from way back then proof too that not everything from the old days of US manufacturing was great thought out.
Also give a thought if you have one of these to checking out the oil
These machines are supposed to use Sae10. Not the W as in winter version.
My machine had entirely the wrong oil in it never mind its state when i got it.
Do an oil change and make sure to clean out the casting before you replace things. Even after my oil change, when i took my "new" oil out it is full of iron filings and bits. So i will be putting new stuff in again.
Cannot wait get the new parts Monday.
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