Ps 420 not happy

[sean_hogan]

My new ps420 jigsaw that I was using on Sunday decided too shot sparks and completely melt my blade, I was cutting a notch in a 3x3 post with the thicker gold blade that comes with it and it started smoking then the heat build up melted everything and now I can't even get the blade out because its welded itself too the guide, also before it broke a few times it would not release the blade because when I was switching the machine of the arbour was stopping at the bottom making the release button on the side useless as it was missing the point where in pushes the arbour round.

 

[Davej]

Did you adjust  the guide to the thicker blade. It Looks like tbe blade guides were too tight and caused the blade to heat up and weld itself to the guide .

 

[sean_hogan]

Yes, every time I change the blade I adjust the guides, which is also a pain in the backside

 

[peter halle]

When the blade is in the fully up position how much of the blade extends down past the base?  

Peter

 

[Holzhacker]

Based on the curvature of the blade I'd say you were trying to feed too fast.
I've cut quite a few notches in 4x4 treated with my Trion (older one), had a few broken blades at first until I figured out the feed rate. I think the longer and/or thicker blade may torque more thereby having more heat.
Since I don't have the new jigsaw my remarks could of course be a complete load of ------  [censored]

 

[Kev]

When you say "a notch", were you cutting in a manner where the blade didn't pass completely through the material?

 

[dsweetser]

Looking at the second picture, you blade guides are too tight. The blade should be able to go all the way back and move easily forward and back.  In the third picture the blade doesn't even reach the roller bearing. 

 

[Administrator_JSVN]

I agree with Don. In the third and fourth photos, there appears to be severe wear on the back side of the blade from the jaws clamping down. That wear extends about 1" (25mm) which is the stroke length.

 

[Rick Christopherson]

I'm sorry you had a problem with the saw. However, from your second and third photographs, it is very clear that your blade guide was incorrectly set.

When you are setting your blade guides, the pendulum action is at its minimum position (regardless of the lever position), so you may not realize that during normal operation the blade will slide between the jaws of the guides much deeper than during your setting. If you adjusted your blade guides only to the V-portion of the guides without realizing that the blade needs to land much deeper between the jaws, then this can cause the overheating that you experienced.

Picture #2 clearly shows the little molten blob of metal from the blade itself getting cut by the carbide jaws of the blade guides.

Picture #3 clearly shows that the area of the blade being overheated coincides with the location of the carbide jaws of the blade guide.

I am really glad you posted this. This is something very important to know that should be passed on to future owners of the saw in terms of the importance of properly setting the jaws of the guides. I suspected that there may be a risk of users setting the jaws too tight, and you have supported the need to make sure that people better understand this. I will do what I can to make sure this is better understood in the Supplemental Manual.

Edit: By the way, picture #2 is fantastic. You must have used a nice macro lens for that. Nice shot!

 

[Rick Christopherson]

By the way, you have seriously overheated the components of your saw. I do not know if this is covered under warranty or not, but I do suggest you bring your saw in for a service inspection anyway. The carbide jaws may be able to handle the heat, but I suspect your backup roller may be damaged.

 

[Rick Christopherson]

..... I was cutting a notch in a 3x3 post ........ also before it broke a few times ........

After re-reading this discussion later tonight, this is another thing that has me a little confused and/or concerned. You indicated that you were notching a 3x3 post, but the blade that you were using has a maximum cutting capacity of only 2-1/8". Does this mean you were trying to cut a notch by not cutting fully through the thickness of the material?

While it is feasible to cut a notch with a circular saw by limiting the depth of cut, this is not something that can be accomplished using a jigsaw. When using a jigsaw, the blade must always be long enough to cut fully through the thickness of the material. In order to cut any material thicker than 2-1/8", you must use at least a 105mm blade (the next size up).

The top 20mm of the blade's rated length never exits below the saw. So when determining the required blade length, you need to add at least 20 to 25 mm (about 1") to the thickness of your workpiece. Therefore, even though your workpiece may have been 3" (75mm) thick, it cannot be cut using a 75mm blade. You must use a 105mm blade.

If my reading of this is correct, it would also explain why you broke several blades before melting down for the last time. The tip of the blade cannot cut the bottom of a trough like a circular saw can do. The first tooth is about 1/8" above the tip of the blade. So for every stroke of the blade, the depth of the trough you cut will continually get shallower and shallower. But because you are forcing the blade down into this ever-shallowing trough, the tip of the blade is going to keep hammering at the bottom of the trough until it begins to bend backward.

 

[jmbfestool]

What Rick said +1

Quick summary

Guides look like they are set to tight (maybe)

Wrong blade length for thickness of material being cut.

To much force you should of stopped alot sooner. You would of felt resistance soon as you entered the timber.

Sorry dude!

Oh!

Although its possible to cut timber when the blade just passes through you must cut very slowly and should only be done on soft materials and because your to lazy to get a longer blade or don't have one to hand.

If possible always use a blade which sticks past the material thickness when the blade is at its shortest length.  This will give you the quickest straightest cleanest cut with out any strain on your blade or jigsaw.

Imagen you using a hand saw and cutting something but never going right through with your tip.  Like cutting out a sqaure in the middle of plywood.  It's hard slow untill your eventually get right through it become easier!

Jigsaws are the same they like to cut all the way through at all times.

 

[Rick Christopherson]

What Rick said +1

If JMB agrees with me, Then there is only one outcome for us all........

[attachimg=#]

[big grin] [big grin] [big grin] [big grin] [big grin] [big grin]

 

[jmbfestool]

What Rick said +1

If JMB agrees with me, Then there is only one outcome for us all........

[attachimg=#]

[big grin] [big grin] [big grin] [big grin] [big grin] [big grin]

Ha lol I think I agreed with you once or twice before?

A friendship is forming lol

[eek]

 

[Rick Christopherson]

Ha lol I think I agreed with you once or twice before?

Yes, and I grabbed the nearest safety pole I could find....I was sure the world was coming to an end the first time!  [big grin] [big grin] [big grin]

 

[Stone Message]

I think that Rick has hit the nail on the head. The blade is too short for the task, the guides were probably not adjusted correctly and too much pressure was being applied. The heating must have caused some burning - I usually stop and check what is going wrong at the first sign of overheating.

I have cut 120 mm thick oak and 110 mm hard maple with a battery powered 420 with no problem whatsoever - the hard maple is shown on one of my videos.



Peter

 

[SittingElf]

Hey Peter!

I know you're spending inordinate amount of time playing with your new Wacom Intuos 5, but we're missing you on YouTube.  What"s up?  We want videos!!

Cheers!

 

[Timtool]

I agree with all the comments above, when setting the jaws you need to push the blade against the rear roller and then tighten the jaws until they touch the blade, and then loosen the jaws a half turn. It IS an annoying procedure and shouldn't exist on a Festool jigsaw in 2013.
I had to order a handful of adjusting screws for mine because every 6 months the screw head is too worn/damaged to be used.

And if the blade stops in the wrong position, you just push the blade back up by pressing the saw down against something. It happens to mine occasionally.

 

[rdesigns]

In addition to what others have said about adjusting the carbide guides, I want to add my experience that was similar to yours when I used the thicker gold Festool blades for the first time:

I had adjusted the guides to accommodate the thicker blade, but was still getting burning of the blade. I realized that the true problem was not with the gap between the guides themselves, but with the ARM that houses the guides. That arm was still set to center the guides on a thin blade, and when you adjust the guides, you only adjust one side of the guides, so that there's a slight difference in the alignment between the guide arm assembly and the roller above it. The blade will run without overheating until you start pushing it thru a cut, which then creates excessive side pressure on one of the guides.

The problem went away after I adjusted the arm position to center the properly adjusted guides on a new thick blade. The adjustment screw for the arm shows clearly in one of your photos.

 

[Stone Message]

Hey Peter!

I know you're spending inordinate amount of time playing with your new Wacom Intuos 5, but we're missing you on YouTube.  What"s up?  We want videos!!

Cheers!

Videos are on the way. I have been on a 4 week European tour testing a brand new Satnav device (a brilliant piece of kit). I have a Q&A video in the pipeline and I am about to embark on some router table work. Just let me unpack the suitcase, dust the camera off and re-learn how to edit videos!

Peter