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My 12 year old Black & Decker 7308 Type 7, 230 Volt A.C corded circular saw is struggling to rip 12 mm plywood; I have changed the blade and it still struggles to rip. Can you help me diagnose the problem?

  • I tried to cut a 30 mm thick wood, but it was struggling to cut and so I stopped. Afterwards it even struggles to cut 12 mm thick plywood. (not enough torque)
  • Does the motor need rewinding to improve the torque?

Thanks

  • Yo may be right, cause All these years I had used the saw to rip max. 19 mm. Yesterday I tried to rip a 30 mm wooden plank, that's when I noticed its difficulty and then I tried the 12 mm. Again it was ripping the 12 mm with difficulty . Possibly a bushing/ bearing could have worn out, will take a look at it and update accordingly. thanks so much. (its corded) – Patrick Vaz Jun 3 '15 at 16:42
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Honestly, a 12 year old black and decker probably needs to go to the scrap yard. Low end saws are not built to be rebuildable, at least since the late 20th century (some 50 year old "low end" saws were a lot less "low end" in construction) - a 21st century low-end saw was usually built with "planned obsolescence" from the design phase forward.

Provide the exact model of your saw to check some details.

The one thing (if that's been left serviceable on this model) it might be worth trying is to replace the brushes if they are excessively worn. Beyond that, replacing the saw is far more likely to be cost-effective.

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    Cheap consumer Black & Decker/Sears saws are somewhat notorious for limited life span. If you can find a B&D repair center near you, they may be able to rebuild it for a reasonable fee... or may not. B&D does make some higher-end tools, bit of course they cost more. – keshlam Jun 3 '15 at 14:37
  • its, Black & Decker 7308 Type 7, 230 Volts A.C and its corded. thanks so much – Patrick Vaz Jun 3 '15 at 16:45
  • ereplacementparts.com/images/black_and_decker/7308_Type_7.pdf If you see a lot of sparking at the end cover you may find improvement from replacing brushes. But the whole thing is done with sleeve bearings, and then there's the "heatsink" that seems to be where there ought to be a bearing at the brush end of the armature. Not quite as bad as the ones that use the case as a bearing, but not an encouraging sign. Unplug, pop off the end cover & have a look. – Ecnerwal Jun 3 '15 at 18:25
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This could be a bearing problem where the main bearings have dried out and are starting to seize up.

If the saw has seen lots and lots of use over its life time it is possible that the motor brushes are failing and need replacement. (Note that this would primarily apply to an AC powered tool).

If the saw is a battery powered unit the problem may be that the battery pack is so far gone that it has built up an internal resistance that limits the ability to deliver the needed current to the saw motor.

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    3 B's.. brushes, bearings, batteries. :) – TX Turner Jun 3 '15 at 14:11

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