Table saw gap

[GrahamIreland]

I have a small shop - Evolution rage table saw.

Whenever I rip a board - the edge always comes out with a slight gap / sag toward middle of cut.

Its only 1/2 a mm or so, but always along the middle.

Can anyone explain this phenomenon to me!



thanks
Graham

 

[Essex Barn Workshop]

I'm not sure why this is happening, but if it was happening to me I think I'd start by making a zero clearance insert plate.
Plenty of you tube videos to choose from, but I like WWfMM so have copied the link to his version:

 

[Doug B]

Could it be your fence isn’t perfectly straight?

 

[Avery]

I have a small shop - Evolution rage table saw.

Whenever I rip a board - the edge always comes out with a slight gap / sag toward middle of cut.

Its only 1/2 a mm or so, but always along the middle.

Can anyone explain this phenomenon to me!



thanks
Graham

I have a similar issue on long cuts and my panel saw is a massive SCM. I have heard other furniture makers bemoan tha annoying curved cut. I put it down to blade resistance that nends the blade slightly towards the board as its cutting.
Its the only thing that makes sense as the gap isnt on the ends which would make more sense if it was operator error.
Its annoying alright. Sometimes i plane my cuts after if it really matters and i always cut oversize and then recut

 

[GrahamIreland]

I think you may be right Avery, perhaps the blade is a bit worn now.
I don't know.

could be what Doug says too about fence, as theres always a slight bit of play in it.

I guess you get what you pay for.

Ill make do thanks.

 

[baldkev]

For repeated cuts you can clamp a batten across the table at 90° to the fence to stop it wriggling ( if the fence is to the right of the blade, the batten would be to the right of the fence )

Might also be worth looking on google for your saw to see if theres fence adjustment or if people have got a workaround.

 

[NetBlindPaul]

I would be looking at the straightness of the fence or the gap between the fence at the point of cut, i.e leading edge of blade and the gap to the trailing edge.
That is check for “back cutting”.
I would have with the machine safely isolated from all sources of energy, brought the fence as close to the blade as possible and measured the gap, with feeler blades or some kind of slip gauge, between the fence and the nearest edge of a blade tooth. As near to the table surface as possible.
Rotate the blade and repeat at the trailing edge.
The gap must be greater at the back, not by much, fractions of a mm, up to a mm or two, depending on how big the blade is.
The other thing then is a good engineering straight edge along the fence. Check with feeler blades for a gap, a 0.05mm / .0015” (thou and a half) shouldn’t fit down.
Then cut a square off the fence larger than the blade and see if it is square (diagonals), & straight sided (steel straight edge).

Once that is done, if you have a sliding table then you can go on to start looking at that.

I have somewhere the definitive document that the industry refers to for the procedure for aligning fences and sliding tables written by a guy from Altendorf.
Where it is now I don’t know.
IF I ever find it I’ll post it.

@Avery, did you have the saw from new? Have you had the problem since it was new? Have you spoken to SCM about the problem? I know I have done visits for less serious issues for them and Record Power over the years.

 

[GrahamIreland]

cheers Paul, sound advice.

I'll get a straight edge and start measuring.

 

[marcros]

there was a thread a few weeks ago about this happening on either a felder or hammer machine on sheet material. The consensus (from people that do hundreds or more of cuts per day) was that it is one of those things, branded sheet goods helped and it was accepted practice to make a cut nearly where needed and a second to exact dimensions.