Hello and requesting help with "flexing" blade issue

[Iguanadon]

Hi Everyone,

 

I’m hoping to gain some knowledge from those more practiced and skilled. 

 

The basics… using Dewalt DW788 and enjoy making dinosaur “puzzles†out of ¾†pine.  Here is a snapshot taken of a batch I made for the first grade classes at the local elementary school last week. 

 

http://content.screencast.com/users/Iguanadon/folders/Jing/media/3443d738-a51a-4001-b352-d7272b1da8f5/2016-03-14_1255.png

 

So, using soft pine, not having any issues at all as I’ve made over 50 of these so far.  All pieces slide in and out nicely from either direction, however… I decided I wanted to start making some “nicer†versions using hardwood.  Using ¾†oak, no problems, but I got hold of some beautiful black walnut and the first one I tried cutting, I thought everything was going well, until I tried to put the pieces together… they slide out in one direction but not the other.  After being perplexed for a bit, because I knew my blade was a perfect 90 degrees, I realized I’m bending/flexing the blade as I’m cutting the harder wood and of course that’s causing all sorts of issues.  No matter how slow I think I’m going, I’m having this issue and can clearly see the imperfection when studying the cutouts.

 

I’m using Olson PGT blades.  With the pine I'm using the 7R because I’m painting them by dipping the pieces in watered down paint and they swell slightly from the liquid.  With the oak and black walnut I use the 5R blade because it’s a bit thinner and I don’t paint the oak and want the pieces to have minimal gaps.

 

I guess I know that the answer is either “slow down even more while cuttingâ€, even though I think no matter how slow I go while making the sharp turns, I’ll never be able to stop putting side pressure on the blade, or possibly use thicker blades in which case I’d like suggestions of what blades to try.  Or, if there is some secret that someone can share with me, I’d be very appreciative.  Otherwise I guess I’ll take a half step back with the hardness of wood I’m using until my skill level rises.

 

Thanks in advance,

Scott

Edited March 21, 2016 by Iguanadon

[amazingkevin]

Hi Everyone,

 

I’m hoping to gain some knowledge from those more practiced and skilled. 

 

The basics… using Dewalt DW788 and enjoy making dinosaur “puzzles†out of ¾†pine.  Here is a snapshot taken of a batch I made for the first grade classes at the local elementary school last week. 

 

http://content.screencast.com/users/Iguanadon/folders/Jing/media/3443d738-a51a-4001-b352-d7272b1da8f5/2016-03-14_1255.png

 

So, using soft pine, not having any issues at all as I’ve made over 50 of these so far.  All pieces slide in and out nicely from either direction, however… I decided I wanted to start making some “nicer†versions using hardwood.  Using ¾†oak, no problems, but I got hold of some beautiful black walnut and the first one I tried cutting, I thought everything was going well, until I tried to put the pieces together… they slide out in one direction but not the other.  After being perplexed for a bit, because I knew my blade was a perfect 90 degrees, I realized I’m bending/flexing the blade as I’m cutting the harder wood and of course that’s causing all sorts of issues.  No matter how slow I think I’m going, I’m having this issue and can clearly see the imperfection when studying the cutouts.

 

I’m using Olson PGT blades.  I use the 7R for the pine because I’m painting them by dipping the pieces in watered down paint and they swell slightly from the liquid.  With the oak I use the 5R blade because it’s a bit thinner and I don’t paint the oak and want the pieces to have minimal gaps.

 

I guess I know that the answer is either “slow down even more while cuttingâ€, even though I think no matter how slow I go while making the sharp turns, I’ll never be able to stop putting side pressure on the blade, or possibly use thicker blades in which case I’d like suggestions of what blades to try.  Or, if there is some secret that someone can share with me, I’d be very appreciative.  Otherwise I guess I’ll take a half step back with the hardness of wood I’m using until my skill level rises.

 

Thanks in advance,

Scott

Why Do Scroll Saw Blades Break? And how do I prevent it?

Another reason is oil from your skin.When choosing a blade don't touch the end of it with your oily finger tips.

[WayneMahler]

I would try to slow down your feed speed quite a bit. Make sure you are at dead on 90 degrees too. When pushing very hard wood past a scroll saw blade they will tend to wander a bit. I take a diamond file and gently clean up the back of the blades to remove any burr left from the manufacturing process. Clear packing tape over the pattern is a must for lubrication also. Not sure how much help this will be, but these are the basic things I always check or do when using a very hard wood. 

[Scrappile]

Scott, sorry I can't suggest anything to help, I have not done similar cutting on a scroll saw, so I know nothing.  But I would like to welcome you to the forum and hope you get the help you need.  I am sure you well, lots of knowledge here on all aspects of scrolling.

[Young_Scroller]

I have a few suggestions, first of all, I have heard that the olson pgt arent as good as the regular blades. second of all, I personally think that a no.5 blade is small for cutting 3.4 inch hardwood but others might think differently, I would probably use a no7 blade maybe  larger. another thing you could do is increase the tension on the blade in order to make it tighter therefore flex less. Final thing is go VERY slow when cutting thick hardwoods like oak. Hope this helps

-Joe

[dgman]

You need high tension on the blade. You want to hear a high "plng" when you pluck the blade. You need to slow down your feed rate. Let the blade do the cutting, and you need to learn to not apply lateral pressure to the blade when cutting curves.

The Olsen PGT blades are ok for cutting gentle curves, but not for tight curves, especially in hardwoods. I use Flying Dutchman Ultra Reverse Blades for hardwoods. For 3/4" puzzles in hardwoods, I would use a #5.

Welcome to the Village and visit often!

 

P.S. Great job on your puzzles!

[Phantom Scroller]

First post Hello. WELCOME to the forum. Roly

[Iguanadon]

Thanks for the Welcome, thoughts and suggestions.  I've ordered various Flying Dutchman blades to try out and have some various hardwoods also on the way.  The learning experience continues.  I'll also tinker with RPM speeds.

 

I look forward to taking advantage of the community brain trust.

Edited March 21, 2016 by Iguanadon

[ike]

I have no problems with walnut it could be your speed is too fast I useally use  speed l5 on my DW788 . When cutting when you stop touch the blade if it is hot you are defently useing too much speed.

[Jim Finn]

I had a similar problem years ago when I was making thick puzzles and found I needed to change blades often , slow way down on feed rate, slow down saw speed, make longer sweeping turns, and tension the blade as much as possible.

[bgloyn]

You have to learn to slow down and let the blade do the cutting. I cut 3/4 puzzles mostly with #3 olson mach speed, prefer the way they turn. I have cut with #1 FDUR, tight fitting, but you have to go slow and wait for the blade to catch up when doing the tight turns on the keys. The easiest way I have found is to pause and let the blade catch up then go slow through the tight turns. Saw is ex 21 and the speed is always wide open.

 

This works for me try it and find what works for you.

[Lucky2]

Speed and tension, if you have the speed set right and the tension is taught then you should have no issues. You have to be able to not apply lateral pressure while cutting, otherwise, you'll always have issues.

Len

[Sam777]

You need high tension on the blade. You want to hear a high "plng" when you pluck the blade. You need to slow down your feed rate. Let the blade do the cutting, and you need to learn to not apply lateral pressure to the blade when cutting curves.

The Olsen PGT blades are ok for cutting gentle curves, but not for tight curves, especially in hardwoods. I use Flying Dutchman Ultra Reverse Blades for hardwoods. For 3/4" puzzles in hardwoods, I would use a #5.

Welcome to the Village and visit often!

 

P.S. Great job on your puzzles!

I agree with Dan,

I am also new to this. Couple of weeks ago, I posted the same problem and I was frustrated. I found out that my tension was not enough. I had to tension the blade quite a bit and my similar problem is ALMOST gone.

Tension, low pressure on the blade and CHANGE THE BLADE OFTEN. You will see the difference as soon as you put a new blade.

Please let us know what fixes the problem.

Sam