Help diagnose tracksaw problem

[derekcohen]

Last weekend a friend came around for help in building a cabinet for a bathroom. The top is a 2" thick Jarrah slab with a live edge. Sawing the ends was a task for my tracksaw, and I set this up and made a few cuts. They were rough and really poor. I have never seen this before. The last time I used this tracksaw was about a month ago, and it produced clean and defined saw cuts. Also, as I recall, the kerf was narrower in the past. This suggested to me that either the blade was loose or damaged. I looked for these and could not find any evidence.

The tracksaw is a 20-year old Festool AT65E, which is in truly excellent condition. I purchased it about 18 months ago, and it looked like it had minimal use. The blade is almost new (one I replaced). Now I do recall cleaning the saw and taking a cut about a month ago, and the blade being slightly loose, and it rubbed against the chassis. I tightened it, used it, and all appeared well. That is the only possible "bump" I can think of.

I took the saw in to a Festool agent this week, explained the situation, and collected the saw yesterday. They said that they could not find any problems. I had questioned whether the arbor was loose or whether a bearing was worn, and they said there was no evidence of either. Today I took some cuts, and the problem was still there. Here are the cuts in Jarrah and some other hardwood ...





The interesting thing is that the cuts are clean at the offcut side ...



I do have another blade, brand new and unused, which came with the saw. This is cheapish and thin-kerf, but the same size and number of teeth. Here are the cuts (burning evident) ...



Here is the saw blade ...



Close up of the size ...



There is the track itself. This is a Makita, but the fit is good, all appears straight and clean, and unlikely to be affecting the result.

Finally, there is no play in any part of the saw bracket.

I keep coming back to a bearing (but there is no unusual noise) or play in the arbor - I can feel a minute but of play with the blade off, but not with it on - if there was play, how much is needed to cause such a rough cut, and why only on one side of (both) blades and not the other?

Okay friends, what are your diagnoses and recommendations?

Regards from Perth

Derek

 

[tjbnwi]

I had to look up the wood;
https://www.wood-database.com/jarrah/

It is a fairly hard wood and the specs say it’s hard to machine. Have you performed the same operation on the same wood previously?

I would try a new or freshly sharpened blade.

I would not bother with the thin kerf blade, it appears to be flexing under load.

Tom

 

[Lincoln]

Looks like one of the teeth must be damaged, on the cut side. That the cheapo blade is cutting reasonably cleanly indicates it's not the saw.

 

[derekcohen]

Looks like one of the teeth must be damaged, on the cut side. That the cheapo blade is cutting reasonably cleanly indicates it's not the saw.

Lincoln, the cheap blade cuts with a great deal of burning - which suggests an out-of-alignment, but I checked for this. The only clean cuts are on the offcut side.

If it was a chipped tooth, then I would expect swirls on the cut face. Is that reasonable?

Regards from Perth

Derek

 

[derekcohen]

I had to look up the wood;
https://www.wood-database.com/jarrah/

It is a fairly hard wood and the specs say it’s hard to machine. Have you performed the same operation on the same wood previously?

I would try a new or freshly sharpened blade.

I would not bother with the thin kerf blade, it appears to be flexing under load.

Tom

Tom, the week before I was cross cutting 2" thick Hard Maple. No problems at all.



Regards from Perth

Derek

 

[derekcohen]

More ..

The blade is set up square. The cuts are square.

Here is a kerf cut in MDF. The kerf should be 2.8mm wide. It is around 5mm here, and it has a double depression. Have you seen anything like this before? It appears to be to be the result of the teeth end moving (and the blade is locked down solid).



Regards from Perth

Derek

 

[squall_line]

The body of the saw has blade marks on it, and is in fact even trimmed from original near the back of the blade, from the indications of the pictures.

It almost looks like one or more teeth are installed incorrectly on the left (as you push the saw forward) part of the blade (the unpainted side), or one came loose. If the blade was wobbling, I would expect the bottom of the kerf cuts to be rounded rather than have two distinct grooves, whereas your picture shows the left kerf has the shape of the tooth profile while the right half of the kerf is flat-bottomed, indicating that multiple teeth in both directions are in that part of the kerf.

 

[derekcohen]

mmm ... sounding like the blade ... how could I check this without another blade (and noting that the thin blade did not play well)? Find another blade>

Regards from Perth

Derek

 

[derekcohen]

SOLVED!!!

I was convinced by now it was the blade. Taking a closer look at the teeth ... can you spot it?



In case you are blind as a bat ....



I tapped the blade back into position - I probably should be looking at a new blade, but thought that this would be the best way to check that this was the culprit. So ...

Fresh cut off, and look at the MDF kerf ...



[cool]

Regards from Perh

Derek

 

[Willy Eckerslike]

I imagine it's wrecked your splinter guard as well.

 

[derekcohen]

Yes, but not so much "chewed up" as slightly shorter and a little fuzzy. Not enough to send a clear message, but enough to notice later. I shall re-site it. That last clean cut was completed with the existing splinter guard.

Regards from Perth

Dere

 

[bobtskutter]

Thank you for taking the time to post all the details.  This is something I'll make sure to remember!

Regards
Bob

 

[Cheese]

Glad that you're good to go... [smile] ...but I wonder what caused it in the first place?

The blade is retracted into the housing 100% of the time when it's not in use so it couldn't catch on something if the saw was pulled sideways.
You didn't mention anything about hitting a knot or some other hard item. That's a strange one. Was it difficult to put the errant teeth back into position?

 

[Packard]

Straightening saw teeth at home is sort of like re-rolling toilet paper that your cat unrolled.  You can get the unwound paper back onto the roll, but it will never be quite right.

Maybe a Festool drill would do a better job.

 

[derekcohen]

A new blade has been ordered in any event. The tooth on this blade looks fine. I used a drift pin to bend it back, hitting the body and not the carbide. This is some solid steel. Makes you wonder how it bent in the first place. This could not occur by placing the saw (which retracts) on something. I'll keep this blade as a back up ... may grind off the tooth to be safe.

Regards from Perth

Derek

 

[squall_line]

SOLVED!!!

I was convinced by now it was the blade. Taking a closer look at the teeth ... can you spot it?

Yeah, that definitely seems "less than ideal".  [blink]

Glad to see it was as "simple" as that!

 

[hamsey]

Nothing to add but found it very interesting and educational