Mitre saw 'burn' mark

[BelfastGuy82]

I cut eight timber joist legs for some very basic tables. Each one ended up with the same 'burn' mark with a slight indentation. Don't know why it happens, but obviously it needs to stop. I was cutting with this.

 

[Harry Bloomfield]

I cut eight timber joist legs for some very basic tables. Each one ended up with the same 'burn' mark with a slight indentation. Don't know why it happens, but obviously it needs to stop. I was cutting with this.

Either the blade is not as sharp as it should be, or you are rushing the cut.

 

[Deleted member 323070]

Check that the fence is square to the blade, and your timber is held tight to the fence.

It's also possible that any resin in the timber can bind the blade a little to cause scorch marks.

 

[GhostIntMachine]

Either the blade is not as sharp as it should be, or you are rushing the cut.

Whilst I agree with you in general, if the saw was being run without a vacuum it is just as likely that the gullets on the saw blade are becoming (over-)loaded with swarf (saw dust) - in which case making too slow a cut can also cause scorching

 

[big-all]

another possibility
if you are using a length stop and you raise the blade with it still turning one or both bits can lift/move and pinch the blade so always stop the blade before lifting or moving the the saw head

 

[Munroast]

curious why they are all the same

are you using it as a chop saw or like a radial saw (sliding it across)
and is that make always from the same side of the blade (and is the other side cutting clean)

burn marks are often a sign of a blunt blade, but even a blunt blade should cut that low quality softwood with ease

and have you got a photo of the blade to see what you are cutting with

 

[foxhole]

Not holding timber down will cause that .

 

[big-all]

curious why they are all the same

this is why i think its lifting/moving the blade whilst still turning as the bit that moves increases in length a fraction as it goes a bit diagonal and pinches the blade

 

[JohnD]

If the tool is hand held, it can move or tilt as you get through the timber and the weight balance changes. This usually happens just as you cut through.

 

[Munroast]

I wonder if he is using a stop to the right of the blade (the stop being something the wood is pushed up against to get a repeatable length) then after the cut when the blade is lifted back up it catches the end of the piece that has just been cut off, this loose bit of wood is trapped between blade and end stop (potentially dangerous)

when the stop is on the left, our hand has that bit held down, and the now loose bit to the right just naturally moves away from the blade


It is bad practice to put the stop to the right of the blade, but many people do it
and on occasions when you have to, then after the cut I hold the saw down until it stops spinnig before gently lifting it back up.

 

[GhostIntMachine]

It is bad practice to put the stop to the right of the blade, but many people do it
and on occasions when you have to, then after the cut I hold the saw down until it stops spinnig before gently lifting it back up.

Then just how do you propose making multiple identical cuts on a crosscut saw? Without a stop of some description that is simply impossible. It is generally accepted that people who are right handed should use their left hand to hold work against the fence and their right hand to control the saw head - which is the method shown in HSE Leaflet WIS36 (Safe use of manually operated cross cut saws). So that only leaves the right side of the saw for the length stop to go. How to use a right side stop safely, then? And you answer that question yourself - if the piece being cut is short and a potentially be picked up by the saw blade you need make the downwards cut into the timber (and then back towards the fence on sliding saws) and then release the power and allowing the blade to spin to a stop before raising the head. This approach is recommended by both Makita and deWalt in their SCMS manuals. Any other method risks the blade picking up the cut to length piece and ejecting it from the saw. In practice, though, it is only necessary to let the blade run down to a stop before lifting the head on very short pieces as the weight of longer pieces makes an ejection less likely. So no, not bad practice if you use the saw safely.

If you are still concerned about this, making up an L-profile auxilliary back fence and bed, screwed rigidly to the machine's back, provides more supportto the cut and makes ejection of shory pieces much less likely. Try it

 

[Munroast]

Then just how do you propose making multiple identical cuts on a crosscut saw?

Have the stop on the left hand side !

clearly you didn't read my post, the bit you printed out in bold - is the same as the bit you quoted from me, you didn't even read the bit you quoted back to me

 

[big-all]

i always work left to right with stop on the right
any thing else is contrary to natural movement to me and involves either left hand pulling work past blade or right hand pushing through to stop if working right to left
i do try and restrict the stop to a single point/edge as close to the fence as possible to minimise the chance off hooking up on the blade

 

[Munroast]

i always work left to right with stop on the right
any thing else is contrary to natural movement to me and involves either left hand pulling work past blade or right hand pushing through to stop if working right to left
i do try and restrict the stop to a single point/edge as close to the fence as possible to minimise the chance off hooking up on the blade

do you not find that you damage the edge of the cut whn the blade catches it on the way out?

I agree its more natural to work that way, and if i was cutting rough wood then I may do that way - but fine hardwood stuff, stop to the left (but then I get carried away with such stuff, expensive blades that I may fit just to do a few cuts then take them back off)


Anyways - getting back to the OP, I wonder if a stop to the right and the blade catching it on the way out is causing these curious burn marks ?

 

[big-all]

do you not find that you damage the edge of the cut whn the blade catches it on the way out?

I agree its more natural to work that way, and if i was cutting rough wood then I may do that way - but fine hardwood stuff, stop to the left (but then I get carried away with such stuff, expensive blades that I may fit just to do a few cuts then take them back off)


Anyways - getting back to the OP, I wonder if a stop to the right and the blade catching it on the way out is causing these curious burn marks ?

not in general with a say 3mm from fence/bed length stop as the diagonal deviation is so small it will be around the same or less than the setback off perhaps 0.6mm from blade to tooth edge

and as i said upstream exactly that point was my thoughts

"Anyways - getting back to the OP, I wonder if a stop to the right and the blade catching it on the way out is causing these curious burn marks ?"