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Post by tooltalk on Sept 13, 2023 16:08:45 GMT -5
Hi everyone,
I'm making my first test cuts today with a new Bosch GKT13-225 corded tracksaw. When I tilted it to do a 45 degree cut I was surprised to see the arrow go past 45 on the bevel scale and stop at 46. I then pressed the button to allow a 47 degree cut and was again surprised to see the arrow go past 47 and off the scale by a fair bit. I then went back to the zero stop and noticed the arrow was in between one and zero. So it looks like my scale may be off by at least a degree. See attached photos (Edit: I was trying to upload photos, but got an error saying "Error: This forum has exceeded its attachment space limit. Your file cannot be uploaded.")
Is this common? Am I being too picky to expect better accuracy from a saw like this and how will I know if it's actually cutting at the correct angle? Maybe I need to put a piece of tape over the factory arrow and draw a new one. Seems a shame to have to even consider that on such an expensive tool.
One reason I bought this saw was to do mitre folds on things like columns, faux beams, and floating shelves. One guy who does a lot of this stuff on youtube recommends setting the saw to 45.5 or 46 degrees. Now I'm not sure how I could ever get that kind of accuracy with the Bosch.
Thanks.
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Post by aas on Sept 15, 2023 0:17:37 GMT -5
Do a test cut at 0 degrees and check with a square. Then do 2x test cuts at 45 degrees, put them together and check with a square. If they are both 90 degrees, your scale is off.
I do a lot of mitre folds and it is correct you need to be at 'about' 45.5 or 46 degrees for best results. I adjust the 45 degree stop to go a bit bit more than 45. Don't get hung up on the scale, it's a guide - results are what matters.
I do high end work and couldn't care less if my saw has a scale on it or not - put another way, you don't need a scale for accuracy. Get your 0 degree stop set to give you 90 degree cuts, set your 45 degree stop to give you 45.5 degrees.
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Post by tooltalk on Sept 15, 2023 9:34:38 GMT -5
Thanks for your response. I did a bunch of test cuts yesterday and the stops do seem to be set accurately to cut at 0 and 45, but the scale is definitely off by at least a degree. I put a piece of tape to mark 45, but when I return saw to zero that mark is at -1.
I hear what you're saying about the scale not being necessary if you know saw is cutting accurately. But it was kind of frustrating to have to do so much testing on a brand new saw trying to figure out what angle it was cutting at and whether it was the scale or the stops that were off.
I made a couple test folds with the mitres cut at 46 and the joints seemed a bit loose to me. So I like the idea of setting the 45 degree stop to 45.5. I tried to adjust the set screw yesterday, but it was really tight and is screwed into the plastic button to allow a 47 degree cut. That plastic part was twisting a lot as a I tried to adjust screw. I was worried something was going to break and the screw never moved, so I stopped. I'll take another look at it.
Thanks again.
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Post by aas on Sept 15, 2023 15:22:30 GMT -5
I know the Bosch is similar but identical to the Mafell, I've never used the Bosch so can't comment on the differences. Usually when adjusting stop screws you have to back the saw off from the stop before you adjust it, there shouldn't be a situation where you are twisting plastic...
Release the bevel lock knobs, back the saw off from the stops and try adjusting the screw while it is free from any hindrance.
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Post by tooltalk on Sept 15, 2023 17:19:12 GMT -5
The lock knobs were loose and the saw was backed off from the stops when I tried making the adjustment.
It's kind of hard to describe the Bosch, so I wish I could share a picture. The button release for the 47 degree bevel angle is on an elliptical shaped plastic lever. One end of this lever is attached to the bottom of the bevel scale housing and other end is loose so the 45 preset stop moves out of the way when you push the button. The set screw to adjust the 45 degree stop is in the loose end of this plastic lever.
So when I tried to turn the set screw, the whole lever was twisting. There is a gap of about 3mm around the lever, so my solution was to fold up some business cards to fit into this slot and stabilize the lever. This minimized the twisting and with a long Allen key I was able to crack the set screw. I backed it off about a quarter turn and the stop is now set to 45.5, which I confirmed with a couple tests cuts and a protractor.
My homemade tape arrow now marks the upper end of the bevel scale accurately, but I think the lower end is still off. At least I can now confidently makes cuts at zero or 45.5. Still kind of disappointing to have to go through all this with a brand new saw and for the factory scale to be so unreliable.
Thanks again for your help.
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