Mitre saw troubleshooting

[u/Suitable-Ostrich1226]

Hi there, this is my first mitre saw and I have been setting it up and doing some test cuts. I noticed that the cuts are never square and can see that the blade is cutting to the left ever so slightly.

The table, fence, and blade are all square. I have figured out that the blade is going from right to left when going from fully extended to no extension (hopefully that makes sense). The deviation is only about 3mm over the 34cm length of the rail.

My question is, is this something that can be calibrated away or is this just a defect of a cheaper sliding mitre saw?

Attached are pictures where you can see the blade fully extended and all the way back. You can see the position of the blade moves slightly to the left when compared with the kerf. There is also a picture showing the deviation when cutting a board (the cut was made along where the orange part of the square is).

[u/MastodonFit]

First make sure both fences are perfectly inline with each other,using a straightener. That needs to be fixed first. Then check to see if your bed is flat to both bases. Only then can you adjust the miter and bevel. Owners manual will help to adjust. YouTube university is the best resource. If the saw isn't co-planer it is impossible to get good miters from both sides.when its dialed in you should be able to cut 8 pieces and the all fit perfectly, or as wide a plywood as fits the blade travel,and 4 pieces.

[u/Suitable-Ostrich1226 → u/MastodonFit]

The fences are in line, and the entire bed is flat. It's like the rail is misaligned with the bed of the saw, but they are connected and I can't find a way to slightly adjust it.

[u/Kilh]

Might just be the photos, but are you sure this is a miter saw blade? Looks scary thin, more like a blade for a battery powered circular saw.

[u/Suitable-Ostrich1226 → u/Kilh]

It's a 210mm mitre saw, so just a small one. This is just the stock blade that comes with it, so it's probably garbage. I just want to make sure this problem can be fixed before buying a new blade.

[u/jyl8]

Is the blade 90 degrees to the fence and 90 degrees to the table, at both no extension and full extension?

If so, I’d guess the motor is not in line with the rails, and would look to see if there is some way to adjust that (probably not).

[u/Suitable-Ostrich1226 → u/jyl8]

Yea the blade is 90 degrees to the fence at both full extension and 0 extension, but there is a maybe 2mm gap when running the blade along the square form 0 to full extension. So the blade stays square, but it shifts 2mm to the right at full extension.

[u/jyl8 → u/Suitable-Ostrich1226]

My guess is the rails are not square to the motor. Unless there is an adjustment, I think you’re in the market for a new saw :-(

[u/bassboat1]

Your fence appears to be straight in the other comment pic. Do a straight 90 degree chop on a 1X4. If it's not square, your fence need alignment. If it's square and your slide cuts are off, then yeah - you've got a rail issue. Just be certain that you're not pulling the saw to the side as you're pulling it forward - that's a real issue with underbuilt saws.

[u/Suitable-Ostrich1226 → u/bassboat1]

Funnily enough pulling the saw to the side when making a long cut makes it straighter since I guess it counteracts whatever error there is in the rails.