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Old 03-02-2017, 06:01 AM
JohnBoy's Avatar
JohnBoy JohnBoy is offline
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Default Gutless 12A saw

I've a Makita 5703R circular saw.

it's a 12A 110v saw I run off a transformer. (our mains is 220/230v here but site tools have to be 110v for safety and are run of transformers, or generators)

It's gutless as hell. I mean you wouldnt cut 3 feet of 2 inch timber before it'd die and you have to let it cool off. I've tried a new blade to no major improvement.

Any suggestions as to what to check/test? I rarely use it because it's so gutless I'm as fast myself with a handsaw.
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Old 03-02-2017, 06:50 AM
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I don't have any idea what to look at, brushes maybe? I don't know the model, but I couldn't be happier with my Makita circular saw.

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Old 03-02-2017, 07:07 AM
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When I was still a superintendent I let one of our laborers (aka wheelbarrow pusher) use my circular saw. When I got it back it wouldn't cut for shit.

Turned out the shoe on it was bent just enough to make the blade bind. I don't know what the hell they did to it but it wasn't readily obvious that it was damaged until you tried to cut with it, and the cuts were still relatively square.

I'd check and make sure the shoe is straight and that the blade doesn't wobble. If the cuts are clean and straight than I would look at electrical issues.

If you can plug it into a duplex outlet on your transformer, I would have a buddy stick a voltmeter in the other plug and see what the voltage drop is while you are cutting something.
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Old 03-02-2017, 07:13 AM
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Put a voltmeter across the xformer output terminals (the 110 vac side)
and see if the voltage drops much when working the saw hard.
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Old 03-02-2017, 07:19 AM
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I had the same problem, Matt mentions, with a DeWalt saw.

Also that saw pulls ~1500 watts can your transformer provide
that at a continuous draw?

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Old 03-02-2017, 09:16 AM
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I agree with both points. Check the brushes and verify the power source can put out the required current draw.
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Old 03-02-2017, 10:32 AM
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Originally Posted by JohnBoy View Post
I've a Makita 5703R circular saw.

It's gutless as hell. I mean you wouldn't cut 3 feet of 2 inch timber before it'd die and you have to let it cool off. I've tried a new blade to no major improvement.
John, what does that mean? how does it die?
Does it smoke? How well will the transformer run a borrowed saw?

You could have a weak transformer and that will eventually damage the saw in the same way that running on an undersized extension cord will. Basically starving the machine, causing overheat and failure.
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Old 03-02-2017, 10:55 AM
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A weak transformer iis not how I would describe it an undersized transformer would be a better description.
From the requirement I suspect that the transformer is purchased as a complete item not a made on site set up.
Is it a single transformer feeding all hand tools or are there several around the job site? is there a fuse or breaker built in? What are the rating numbers on the transformer? how long and what wire size is on both the 220 volt and 120 volt sides of the transformer
It does sound like the saw is not getting enough power
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Old 03-02-2017, 11:00 AM
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Next time you use it, check to see if the blade is hot. That would tell you if it is a blade issue.

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Old 03-02-2017, 12:54 PM
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Being an inquisitive person I had to go looking to see what the jobsite transformers were all about. A quick search turned up some interesting info. There are a number of different units out there--I've attached a couple pics for posterity's sake.

The search actually found references to under-sized transformers on a couple European forums--seems like you're not the only one with the problem...
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Measure twice and cut once...or...wait, was that the other way around?
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