Thread: Problem with circular saw base plate

Just draw file it till you remove the high spots.

Thanks for the suggestion and its a good one, but unfortunately I don't think it will work. The lip of the plate, which is thick and strong, is on an angle and the holder/hole for the fence saw guide is way out of whack.

I tried using a bit of force on the offending holder and the only thing it did was to damage the hammer.

Maybe need to post a photo of the offending bit because I thought filing would work too. Maybe a touch with an angle grinder first to remove really high spots. Alternatively, drill and countersink the base and screw a straight batten of timber or metal to run against a straight edge.

Cheers
Michael

What you are after is a track saw like this: Basic Tracksaw Components. | Eurekazone

You could make one with ply or MDF but you'll loose a bit of cutting depth. These track saws are made from aluminium, so they minimise the depth you lose. The main advantage for you is that they eliminate the requirement to have a straight base plate on the saw.

Thanks for the suggestion, but that Tracksaw solution looks like it may be overkill for a part-time, very amateur, hobbyist.

Well get yourself a bit of 4mm aluminium, cut a slot for the blade, and screw your saw to it

Thanks for all the suggestions folks. I have just had a really good look at the base and have discovered another problem. When I measure from the blade to the edge of the plate, there is about a 1/16 of an inch difference between the front and the back.

Me thinks it will be easier to just buy a new circular saw (or possibly a table saw) and be done with it.

$450 gets you one of these...

TradeTools Direct - Serious Tools...Seriously Discounted!

Originally Posted by Master Splinter

$450 gets you one of these...

TradeTools Direct - Serious Tools...Seriously Discounted!

Very Noice; but a bit too serious for my humble usage.

Hi Torb,

since the GMC tool brand in an unknown entity in Holland, i don't know much about your particular circular saw model. A pic would help. But one thing goes for most circular saws; the array of hinges, height adjustment rods and fixation methods is amazingly flimsy on average. All it takes is a mild drop on a hard floor from a modest height, to bend a hinge or fixation point or to warp the bottom plate. This deformation only needs to be ever so slight to seriously impair sawing precision. This is not only so for budget machines, but also for quality brands.

The "lip" that you describe, is probably sticking out in front of the bottom plate? If so, this is a guide that shows in advance the line along which the blade will make its cut. This guide is used to set the parallel guide if there is no other measuring tool at hand or while using the saw free-hand. Such a lip is either spot-welded or riveted or screwed onto the bottom plate. The parallel guide slides within two references, one of which is obviously the lip thingy (with an arresting screw on top) and the other reference is probably a slot or two protruding bits or some bush on the left front corner of the bottom plate, through or between which the parallel guide's transversal bar slides.
The lip part make have been whacked out of place, one of several spot weld points may have loosened or a rivet may have gotten bent or sheared of. It is hard to understand any other way how this part may have come of a 90 degree position. You may have to pry the lip part from the sole and reattach it again (welding, screwing, riveting through new holes). I need to see the situation to make better comments on it.

Now for some general ihints. The best way to readjust the bottom plate and its spotwelded or riveted adjustment parts, is to detach it from the machine first. It's much easier to work on the part with the motor and blade housing bulk out of the way. I always try to find a second machine for comparison and constantly measure the two identical items to establish how i get along. If there is no second machine, there is no alternative but to attach the plate back to the machine again to do some measurements and detach it again for some more treatment, again and again until the job is truly proper.

For the plate itself, a mirror is a perfect "planeness detector". When the sole plate is perfectly smooth, it will not wobble in any way if laid down on the glass. But if the plate is warped , the tiniest bit of wobble can be felt, and the imperfection can also be seen as a crack of light between the glass surface and the plate metal, if held against a light source. The mirror layer has the additional bonus of visibly doubling any deviation through its reflection, making it more distinguishable.

As beating goes, nice and easy does it. Carefully and progressively increase the beating force if it is perfectly clear that, at lesser force, the sole will not budge or will merely spring back due to its own resilience or springiness. Pressed steel is tolerant and can be bent back if the adjustment beating was a bit too much, but cast alloy (especially the magnesium types) can very suddenly crack or tear in an unpredictable way. Still, with patient and lengthy but subtle beating, mazac (MAgnesium/Zinc/Aluminium/Copper) alloys can be brought back in their original shape, provided that the bending is less than 10 degrees and didn't happen in a sharp fold. Be careful about the way you use underlaid parts, to serve as a sort of anvil or to serve as a reference folding line. For instance, when you use a steel bar to precisely support a fold bent upward, in the hope of beating the fold back down exactly across of the line of the steel bar, that same steel bar may provide the line across which the bent piece may break off entirely. With cast alloys, the chances on this happening are very high. Be aware that the entire beating force of your hammer is concentrated on the support surface of the underlying object, and this concentration is very high if the support shape has the thin shape of a line. This is usually the way for stone masons to make a piece of stone break along a predicted or deliberate line.

If riveted or spotwelded upright parts have become untrue to the sole plate (again with shock impact often being the cause), bending or forcing them without supporting their fixation, is a bad idea. You may pry loose a spotweld point or cause play in a rivet, leaving you with an added fault instead of a solved one. Clamp the fixation point down tight to the sole plate first (vise, glue clamp) and only then apply bending force to cure the part in question. Use 90 degree measuring devices to check true-to-base positions from all sides, before reattaching the sole to the machine and checking the result. You may have to repeat this many times before you're done, but that's better than whacking too forcefully and regretting it afterwards. Use rubber or wooden hammers if possible. Steel hammers tend to give harsh and unforgiving blows. Momentum hammers (the ones filled with steel pellets) have softer heads, but their effect is unpredictable.

If some protruding spots underneath the sole are the only worry, then filing down (as suggested several times in the posts above) is the way to go. If the saw blade is not exactly parallel to the bottom plate's sides, then adjustment of the bits on top is called for. A circular saw with a pinching blade caused by a maladjusted sole is a huge nuisance and cannot give you working pleasure and precision. Which is ashame if the rest of the machine is still in fine shape.


You may have noticed that my way of describing the process in the right jargon and phrases is a bit crooked at times, but that's because English is not my native language.

Lots of success!

gerhard

Gerhard, Wow! Thanks for all those very detailed, and well described suggestions.

You are 100% correct. The bit that is sticking out on the lip is indeed the guide hole, but on the right hand leading edge.

The guide support rails mechanism has been pop riveted onto the plate. The whole base plate is solid steel, and the lip, and holes have been made in one piece. The hole would have then been cut and the lip would have then been bend under enormous pressure. Its bloody solid.

I did take the plate off before I started mucking around with it.

The saw has not been dropped. Only I use it and although it was purchased years ago, it sat in the original sealed box until recently.

Your comments about adjusting the top plate to get the blade exactly parallel to the sides is a great one.

Once again, thanks for the help.

Cheers
Ric

Originally Posted by TORB

Hi Good Peoples,

Been lurking for a while but this is my first post and I am hoping someone can help me please.

I have a GMC circular saw that has hardly been used, but now that I have retired, plan to give it a bit of a work out. I plan on making a cutting jig for it so that I can make accurate cuts. No problem there, I have found plenty of good suggestions here that will help me make it.

However, the problem is that the edge (lip) of the base plate on the circular saw is not 100% straight. If I hold a level to it, there are a couple of significantly high spots that will mean straight cuts using a template/jig won't be as good as they would be if the edge was truly straight.

Any suggestions on either how to make a new base plate, or any other possible work arounds?

Cheers
Ric

i reakon make a thin one out of wood or another piece of metal and just attatch it to the base but make sure that the new one is square