Thread: Table saw and melamine burn

Hi Trav,

I am impressed by your analysis of the problem ... I was thinking the splitter/knife might be wider than the kerf and bending a <20mm piece ... but you seem to have that right.

The material you are cutting probably has waterproof resins that will tend to bind to the blade .... I find CNC blade cleaner to be the best product I have found ... why not give it a try.

What happens if you do a faster cut?

Regards

Rob

Is the blade rubbing on the front of the blade or the rear of the blade? You can tell by looking at the shape of the burn marks.

How fast are you feeding? slow and steady trying to maintain the material on the fence? or swift and deliberate? without being a stupid idiot about it, you probably can't feed too fast manually. I use a slider and often try to test myself if I can match the feed speed of a beam saw which is cutting 4x18mm sheets at once....I don't reckon I can feed faster than the beamsaw

Increase your feed rate and see what happens.

+1 change your feed rate

Failing that try to identify if at a certain point your cut starts burning. Eg try a test cut but only cut a quarter, switch off then cut half way etc. It may be the way you're feeding the pieces through the table saw causing it to rub. I just find it unusual than rips under 20mm are ok whilst larger rips causes burning.

Also check where you're applying pressure on the board, google feather board placement to give you an idea of where pressure towards the fence should stop. This will prevent the board from rubbing onto the blade.

Also consider cleaning the blade and applying a lubricant and seeing if that helps.

Thank you guys for taking the time to provide some feedback. Obviously it is hard for you to understand and provide comment on my feed rate. Straight up I kept it slow and steady but I am a novice and hopefully this may help other newbies. I know I need a lot of work on my technique.
I did focus on the where the work piece was in relation to the fence during the cut and not on the blade. Most of my cuts after an adjustment were completed in this manner before I sped up the feed rate. I wasn't throwing it carelessly into the blade but I was feeding it through at a speed more expected in a course rip cut. From memory, I was till getting some burn, not as much, but this increased the chipping and I assumed the strain on the crosscut blade I was using.
I read somewhere that a suggestion with a higher HP motor is to increase the feedrate to keep a little strain on the motor and not let the power polish (burn) the edge of the cut....how true that is I am not sure?
I made an novice assumption (this may not be true) that due to the RPM of the blade and the power driving it that any pause however slight is instantly going to leave a burn on the cut edge compared to saws I am probably used to.

So based on the feedback/suggestions, I will get my hands on some more material and give it a try over the weekend, maybe looking more at my speed and if that fails, I may try the suggestion of a lubricant.

I will also try and tune my ears a bit more to hear whether it sounds if there is any binding at the front or rear of the cut or a change in the noise during any stage of the cut. On a few test cuts it did sound like there was a slight difference in sound when the kerf passed the blade and reached the splitter but my setup tells me everything is aligned which is what is confusing me.

I will also take a wide board and make a series of cuts as Tonzeyd suggested only enough for it to reach the center of the blade and almost like making a featherboard and then I will cross cut the "fingers" off and have a look at the edges. I will then just keep increasing the length of the cut until I can see where the point of burn is occurring.

I also ran a mag featherboard which stops just before the start of the blade to prevent binding

Thank you again and I will let you know where this gets me.

Trav

Your problem with your cuts is quite a conundrum.
The testing/measuring you have done seems to cover the bases without giving any suggestion about a remedy.
Just a couple of things came to my mind while reading through;
1) a triple chip blade, even straight of the box will require more effort to push a panel though it than a more aggressive blade
2) what brand of melamine are you using? Is it from Laminex/Formica or is it from China? We (when I was working) used mainly Laminex board nearly exclusively. Every now and then you would get a sheet that had stresses in it that at times made it very hard to push it through the saw due to the cut closing and jamming on the riving knife.
3) in desperation...what if you adjust the fence to a position just a tad away from the blade. I said desperation (you can always adjust it back) just see if that has an effect.

I have a sliding table panel saw with a triple chip blade and a scribing saw. With all cred to you for all your analysis so far, the only time I have had burn is when I'm even ever so slightly out of square with the fence. Not much help but all I have...

also might be worth checking if the blade is warped/bent/has a raised spot which might cause rubbing

and grab some vernier calipers and measure your rips. are they the same width at start and end of rip? if not something is not in alignment.

Hey Chambezio..Conundrum Yes!.

Melamaine is left over stock I purchased from Bunnings so..assume import from China? Admittedly, it was from the last project I did with my triton workcentre which was the walk in robe. I clearly remember ripping that down and i could see the binding on the factory splitter. The kerf closing in was so noticeable I could diagnose the problem straight away but put it down to being a thin kerf blade in the triton WC. That had a similar issue where on wider cuts, the problem became worse maybe due to more lateral pressure of the offcut?
The thinner the strip the easier it went through. I had to actually reach around the blade guard and insert a wedge in the kerf to complete the cut believe it or not. I would never attempt that on my new Harvey even though the guard is always installed. Funny thing is, even with me stopping half way through the cut using the WC, reaching around installing the wedge and completing the rip, I never got any burn. I was running a 40 tooth Diablo blade at the time.

I can only think that this same left over material is presenting the same problem but the thicker riving knife on the Harvey is minimizing bind on the rear of the blade, the extra grunt is allowing the saw to complete the cut but the higher tooth count is creating additional heat and, in turn, more noticeable burn than that of the 40 tooth rip that I had in the WC? I could be completely wrong of course.

New blade is not warped. I will do some more passes and check the offcuts with my verniers.

Can tension be found in all forms of particle board/melamine or mainly through these cheaper alternatives? I only purchased where I did out of convenience but if this is going to be a regular issue, I am happy to go else where...if in deed it is just stresses and not table saw alignment and/or technique problems.


Thanks again.

Its probably not the best idea to be letting go of the piece and walking around the back/putting hand around the blade, you run the risk of kickback when you let the piece go.

The more i think about it the more I'm leaning towards its likely that its your feed rate/method rather than the hardware as with thinner pieces I suspect you're not putting your hand on that side to push the piece through whilst with larger pieces you're probably more inclined to push on both sides leading to additional lateral movement towards the blade causing the back end of the cut to close in just enough to rub onto the blade. If you have a sled or mitre guage do a few test cuts with that to see if you get burn marks that way.

Finally try with a new piece of melamine, as if the melamine youre using is left over from a previous project it may have absorbed significant moisture depending on how its stored which could cause some movement in the particles when its cut.

Other than that I'm as stumped as you are.

Good luck and hope you identify the cause soon.

It is only on the highest quality panels saws that the fences on the right and left of the blade are in accurate alignment. You will probably find that your outrigger runs out by a mill or more when using the LH fence - reason, over a 2400mm panel, the table drifts to the left. To compensate, you must rip against the right hand fence and feed at a decent rate. If your RH fence drifts to the right (which some argue they should) you will end up with a parallel rip cut.

Use the LH fence only for cross-cutting to length. If your machine isn't in sinc with both fences, you will get burn because the fences are fighting each other. Set the RH fence as best you can with minimal runout to the right and only trust that fence for rip cuts. Set your LH fence square using the 5 cut method and only use that fence for cross cutting. This is the only time that I use the clamp on the bed/sliding table of the saw. If you do, and your saw is not a genuine PS ie accurate, you will always end up with burn. Practice getting parallel cuts using the RH fence using the sliding table for an even feed rate. You shouldn't get any burn using this method on a PS that cost you less than say $40K.

Let me know how you get on using ONLY ONE FENCE. I think out of maybe hundreds on melamine sheets, I've seen only one bind on the back of the splitter.

Originally Posted by Jeff Leslie

It is only on the highest quality panels saws that the fences on the right and left of the blade are in accurate alignment. You will probably find that your outrigger runs out by a mill or more when using the LH fence - reason, over a 2400mm panel, the table drifts to the left. To compensate, you must rip against the right hand fence and feed at a decent rate. If your RH fence drifts to the right (which some argue they should) you will end up with a parallel rip cut.

Use the LH fence only for cross-cutting to length. If your machine isn't in sinc with both fences, you will get burn because the fences are fighting each other. Set the RH fence as best you can with minimal runout to the right and only trust that fence for rip cuts. Set your LH fence square using the 5 cut method and only use that fence for cross cutting. This is the only time that I use the clamp on the bed/sliding table of the saw. If you do, and your saw is not a genuine PS ie accurate, you will always end up with burn. Practice getting parallel cuts using the RH fence using the sliding table for an even feed rate. You shouldn't get any burn using this method on a PS that cost you less than say $40K.

Let me know how you get on using ONLY ONE FENCE. I think out of maybe hundreds on melamine sheets, I've seen only one bind on the back of the splitter.

Hi Jeff,

Thank you for the feedback. I re-adjusted my splitter to be dead centre to the blade (it was almost dead in line with the arbor side) and I also have the fence adjusted to only about .001 - .002 toe out. The general consensus by everyone was feedrate. Being a newbie to a proper shop cabinet saw i didn't realise that my technique and, more importantly, my feedrate needed to be adjusted from what I was used to. I am not used to feeding sheet goods through the blade at the pace I did over the weekend. I thought I would have to slow it down because of the 80 tooth blade I am running but maybe due to power of the TS and the RPM of the blade my slower rate was causing the burn even though my approach was to not over stress the blade and reduce chip-out. I increased my feed substantially on some small cuts over the weekend (only 600mm in length) and surprisingly the TS didn't complain. I got much better cuts without any burn on either edge. I can't believe though how important feeding technique and rate is. Even the slightest pause to reposition the trailing edge hand that is running the board through the TS did create a small burn mark on the cut. The tiniest deviation of the piecework coming away from the fence caused a bit of burn and scalloping of the cut. Without looking at the cuts, I could butt both pieces together and see straight away if I had an issue by sighting a perfectly straight, clean cut line then witness the tiniest of gaps in the joint. Pull the two pieces apart and sure enough there was burning of the wood roughly where I repostioned my hand for completing the cut. It is very unforgiving but not sure if this would be true when ripping with a 22 tooth blade rip blade where a dead clean edge may not be the operators objective or where you arn't working with material containing glues & resins?

This is a pretty boring topic, I know, but hopefully this also helps other newbies starting out.

One thing I was a little lost with was your comment about using a right and left fence ("If your machine isn't in sync with both fences, you will get burn because the fences are fighting each other")?
This must be more related to your pro Panel Saws? In my situation, I would imagine that that a sled would be the alternative to what you are referring to as a left a hand fence?

Anyhow, thank you to everyone that provided some great advise. I have a lot to learn but hopefully instead of obsessing over stupid dial gauge readings I can start to make some real dust now!

Cheers

Trav

Hope that helps, Trav.

Feed rate must be faster rather than slower and keep using the triple cut blade. A mate of mine with a hammer panel saw is still finding his feet, so don't be put off too quickly. The trick is to get an 8 x 4 sheet and rip say 150mm slices off the long length. Use the rip fence on the right, not the crosscut fence on the left. Once you've broken a few sheets down with an even feed rate, you'll get the hang of it. Just don't stop or slow down and let the sliding table do all the work for you!

After you've got your process down pat, lock the sheet on the left side and see what happens. Almost impossible to keep the rip cut running hard against the RH fence. That's when you get burn. I wouldn't even consider using a sled on my panel saw. That's what the LH fence and slider do for you with more accuracy.

Whiteboard costs about $35 a sheet trade so think about investing a few hundred to get your methodology right. You'll use the off-cuts for drawers etc so there would be much waste.

Also, get someone to give you a hand with the big sheets. I've seen young apprentices throw 2400 x 1200 sheets around alone but I am getting too old for that!

Hope this helps, Jeff

I thought I would provide an update to my recent issue of burn marks and lack of experience with using the new table saw.

Since I originally posted the problem and received so much constructive feedback I have spent some time not only on technique but listening to the saw. I also decided to take the plunge and purchased a set of Jessem Stock guides which have assisted greatly. They are not a cheap piece of kit but are very effective and do exactly what they are designed and marketed for.
I recently knocked up a very basic, movable outfeed table and there were about 45 panels in total to be cut down..so a few cuts. Other than maybe a few cuts where I paused (still learning to position my hands for steady feeding) which instantly resulted in some burn, every other cut came out near perfect and when cut edges were placed up against one another, the cut line was extremely tight and crisp and almost entirely cheap free using the Frued 80 tooth blade.
I don't think that I could have consistently achieved these results without the stock guides...maybe with more experience that can happen.

Thanks again for everyone's help.