Thread: Circular saw blade not parrallel with its base

that sounds very weird, try your nearest black & decker warranty agent as they now own porter cable

Hi Interrupt,

you're not ignorant whatsoever, you put it excellently and it is definitely not as it is supposed to be in any circular saw. The base plate is a reference to which the rest of the machine must be true, you must be able to trust on it for accurate results.

I encountered something like this some 20 years ago in a small but very handy Holz Her Derby circular saw. In its design, Holz Her used only one spot-welded piece of profiled steel on which the entire motor/sawblade housing/grip assembly hung. Normally this construction would have been adequate for a 700 Watts saw with a 140 mm blade. There it was in the German tool shop just across the border, for only 95 German Marks (47 Euros), which was a bargain too good to avoid. When i took it home and used it, there was no decent result to be had from it. All sorts of trouble, rough sawlines, burning and smoking, heavy motor load as if the blade was squeezed between the material, which was not far from the truth. I was puzzled because this is a very amazing stupid fault to find in a circular saw and therefore i didn't expect it. When measuring up the entire machine i found the same fault as you drew so precisely. The saw had probably fallen on a hard floor, with the plate impacting probably on one if its corners and the inertia of the motor assembly weight leaning hard on the spot welded steel fixing profile and bending it. It took some time to get it just right again. Even a single degree of maladjustment is enough for the saw blade to experience a lot of unnecessary friction, with the teeth and the blade face forced slightly sideways through the material and scraping along the parted surfaces. When i would have calculated 25 Euros for every labour hour i spent in the thing to get it back to proper adjustment, the purchase would have been less of a bargain. Still, i was fond of the thing and it performed fine after that, so i kept it. I wonder if the tool shop even knew that the thing was bent, they were otherwise very decent people and i had enjoyed many special offers and special discounts there because i was a good customer. They were embarassed when i mentioned it and i got yet more discount on the next machine i bought there. It needn't always be malafide or done on purpous.

Holz Her abandoned this design and all circular saws have now two fixing points for the motor assembly to the base plate. But they can still bend or can be forced slightly out of their original shape, even when made of cast aluminium instead of stamped steel. I encountered a large Metabo saw once that also suffered this fate, but the owner admitted that the machine had also enjoyed a drop on a stone floor.

Vek Tool's advice is absolutely right, see the seller if there is still warranty on the machine, for the damage was done before the tool was handed to you across the shop counter. Preferably make them swap it for a new one instead of tinkering around with this faulty item, for it is a pain to put right and it takes time and a feeling for precision, which many repair shops can not longer afford to offer. So chances are not 100% that a "repaired" machine is 100% accurate again, unless they can prove that both the plate and all the fixing assemblies were replaced by new parts. That is the minimum effort that has to be put into it, less than that is an unacceptable skimpy measure. If they are bonafide and knowledgeable people, they will understand this problem and you will have little trouble with obtaining a replacement.

Lots of success!

gerhard

I have seen this problem several times and it has turned out to be the arbor washer not being seated in the blade correctly, so the effect is a crooked blade to base. Just make sure the arbor washer is firmly seated inside the blade.

Regards Ingin

If that would be the reason, so much for the better. A faulty blade mounting with ill fitting flanges could be easily remedied with a quick disassembly, inspection and reassembly of the blade. It reminds a bit of special "wobbly" flanges that several saw manufactureres had on offer for DIY purposes in the 70's and 80's, with adjustment marks to set the amount of blade wobble. With the setting on zero, the machine offered regular sawing with the saw line as wide as its blade width. With a bit of wobbbling, the saw blade made the saw line much wider, so the circular saw could double as a router, making grooves up to 1/2" width or so.

But judging by the story, i'm afraid that's not what he meant and this may well be a warranty case. Anyway, like you said, a thorough inspection of the blade's fitting will sort out which of the two scenarios is at hand, so your advise is very good.

Originally Posted by ingin1

I have seen this problem several times and it has turned out to be the arbor washer not being seated in the blade correctly, so the effect is a crooked blade to base. Just make sure the arbor washer is firmly seated inside the blade.

Regards Ingin

Very good point, i would tend to agree, i hope it is for your sake it will save you alot of stuffing around.......Ingin maybe you should get a job as a powertool technician most technicians(so called) miss that point

Its common, just not to many realise it. Im not sure about the Porter Cable but you should have screws front and back that attach the saw to the base. Just loosen and tap the front to the side by half a mill, check it out by ripping some board. If needed just repeat

I reread your point Ingin, and i believe you may also have meant the thin ringlike adaptation washer inside the blade's center hole, to make it fit a smaller arbour diameter. I don't know if the mentioned saw model uses such a ring. Those are indeed known to leave their proper seating while the flanges are tightened. When they get squashed in this way they cause blade wobble. There may also be tangential blade deviation.

If this would be the case here, would Porter Cable's quality inspection indeed be to such standards that they would allow machines to leave the factory with such a simple stupid defect? That doesn't sound like the Porter Cable they once were.

It's also something you don't expect. Of the hundreds of saws i took apart over the years, i only encountered this a few times, and that was in used saws, caused by previous users not knowing this. I never saw such omissions caused by factories or by decent repair shops, it's one of those things you check as a rule before handing out a saw back to the owner again, just like a good motor test run and thorough checking for sparks after brush renewal. It's so sloppy that you could put this in the same category as mounting a blade with the teeth pointing backward.