Blade shortening.

[amakah]

Hello, I have a delta scroll saw and although Iam used to working with tools a scroll saw is new to me. I want to be able to cut wooden gears out of 9mm plywood but find that it is difficult to follow a line. As I only want to cut 9mm has anybody tried to shorten the blade so that it is more rigid and perhaps less prone to wander. I am sure that more practise will make my scrolling better as well

 

[Jaco]

9mm is not that thick so cutting should not be an issue.
The blade tension ok?
TPI of the blade?

 

[AES]

I can't see any advantage in shortening the blade, and with most machines, make it much shorter than the standard 5 inches and it won't fit into the machine anymore.

Apart from checking the tension, as mentioned above, can you tell us what blade you're currently using (blade thickness and TPI) please? Also as above, 9 mm ply is not thick so it shouldn't give too many problems if you have the blade tensioned correctly (and in the right was round - so that it cuts on the downward stroke - sounds daft but surprisingly easy to get it wrong).

I don't know the Delta machine personally, but member here Lofty Hermes has several, so if he doesn't show up on this thread soon I suggest sending him a PM.

In the meantime, there's a sticky right at the top of this Scroll Sawing Section which contains, amongst other things, a downloadable "No Fail" blade selection chart which gives good general guidance on which blade to select for which job. There are also downloadable charts by blade manufacturers such as Pegas, showing the complete range of blades they make, with info on TPI, blade material thickness, tooth shape, etc, etc. And there's also info on places to source various blades - e.g. I believe Axminster Tools are the UK distributors for Pegas blades (the blades are made in Switzerland but Pegas do not supply direct to the public).

I don't want to suggest that you're incompetent, NOT at all!. But cutting gears does require some pretty accurate cuts and it you're a beginner you'll likely need some practice on "general cutting" before starting the *real job". Google Scroll Saw exercises and/or YouTube and you'll find several sources of specific exercises designed to build up your cutting accuracy.


HTH

 

[Jaco]

Good reply.

Somewhere in the other threads I posted links to patterns etc.

 

[Sachakins]

Also cheapo blades can make accurate cutting a nightmare. Some are stamped out so poorly the blade cut will always drift.

 

[amakah]

Hello, Thank you all for the information. I do think that I am the problem so I will spend some time practising with a hope to getting better at it.

 

[Johnwa]

Morning Amakah, I have a Delta 40/560 scroll saw and I also had problems with blade wander. After much fiddling and faffing and some help from Lofty Hermes and Andy AES I finalĺy got it sorted. First off get some decent blades, I use Pegas, next get the blade tension right, adjust the small knob on the top of the blade holder assy, screw it in to increase the tension, just a little bit at a time, flick the blade with your nail and listen for a nice high pitched ping and lastly practice on some scrap, 90% of scroll sawing is technique and familiarity, improved accuracy of cuts will come with time. Best of luck
John

 

[Johnwa]

Hello again Amakah, I missed a bit out on the blade tensioning. Before altering the tension, move the tensioning lever to its forward (tension off) position before you adjust the tension knob and then move the lever back to its tensioned position after adjustment. I must stress you only need to adjust by about 1/8 of a turn at a time otherwise I think that there is a possibility of straining the blade assembly and if its an old saw like mine there arent a lot of spares about so treat it gently!

 

[amakah]

Hello, Thank you for the information. I now intend to get some Pegas blades but on looking at them on eBay there seems a lot to choose from, there are spiral once’s as well. As I only want to cut 9mm plywood what would you recommend. Logan.

 

[AES]

PLEASE, consult the downloadable "NO Fail Blade Chart", as suggested above.

Personally, I would use a Pegas No. 3 or 4 blade, of the "MGT" type (Modified Geometry Teeth) for 9 mm ply. But you may be more comfortable with a different blade. And anyway, weren't you going to try some general cutting exercises on some scrap wood before starting those gear wheels?

In which case you may well want to try several different types/sizes of blade. dependant on what scrap wood you have handy. That "No Fail Blade chart will point you in the right direction (and does NOT deal with blades from specific manufacturers).

And if you're confused about things like "Reverse Tooth"; "Skip Tooth", and "Spiral Cut" blades, etc, etc, then I suggest, as per my previous post, you look on YouTube for vids specifically aimed at scrolling beginners. You get cutting exercises as mentioned previously, plus a lot of info on blades such as those examples I quote above.

I would suggest you do what I did. Buy packets of a dozen blades (they're not really expensive) of sizes and TPI to suit your available scrap wood. By the time you've completed a few exercises - and broken a few blades! - you'll have a much clearer idea of what suits you, BEFORE you start on those gear wheels.

Like a lot else in woodworking, you can't get much more than "good general indications" from books, the YouTube, or other people. You have to do a bit of hands-on work yourself so that you develop your own skill of hand and your own "comfort zone" that works best for you. And as you do more and more hands-on, you may well "develop" and "refine" your own choices.

To give a specific example: You mentioned Spiral Cut blades and I included them in my examples of blade types earlier in this post. Having tried spiral cut blades myself, I just could not get on with them - "horrible things"! And several members of this Forum have also tried them and agree - one member here, calls them "the invention of the devil"!! But OTOH there is at least one member here - and several other scrollers elsewhere - who use ONLY Spiral Cut blades and produce superb results.

See what I mean about personal choice/developing your own experience?

Hope all that helps

 

[AES]

@ amakah: You wrote, QUOTE: I now intend to get some Pegas blades but on looking at them on eBay there seems a lot to choose from ..... " UNQUOTE:

Yeah, that's because Pegas, like lots of other blade manufacturers, make a huge range of blades to do just about every cutting job in the book (plus some you probably haven't even thought of yet)!

See my post immediately above this one.

With the greatest respect, just because one or two (or even a lot) of people say "I use Pegas blades" doesn't necessarily mean that you should!

 

[amakah]

Thank you.

 

[Johnwa]

Hi Amakah, as AES says above there are many types of blade for different jobs, but I use Pegas because they are readily available in the UK, I also have Olson(Olsen?) which I use. Personal preference for 9mm ply would be a #5 modified geometry Pegas, or for finer work #3 modified geometry, you'll have to take a lot more care with the #3 blades obviously, be prepared for busted blades if you're not used to them. I can recommend Powertoolcentre on ebay for blades, their prices are competitive and delivery pretty quick, usually a couple of days. Be prepared for recommendations of other types of blades and suppliers, the above are just my personal choice.
Keep practicing
John
PS download the chart that AES told you about or download the one off the Pegas or Olsen? own websites, these tell you which blade you should use for which wood type and thickness. They look a bit daunting at first but soon make sense.

 

[amakah]

Thank you.