Maxing out a Startrite 18 S 10 Bandsaw

[toolsntat]

Ok, I've got to rip down some seriously old pitch pine and wondering if anyone has successfully upped the blade from a standard 1/2" ?
This is the machine

http://www.woodworkuk.co.uk/forum/viewtopic.php?f=6&t=2561Ian at Tuff Saws can do me 3 tpi on 1/2" but I was toying with the idea of something a bit wider. Would there be an advantage in this ?
Cheers, Andy

 

[sneggysteve]

I would take guidance from Ian myself

 

[Sandyn]

+1 for asking Ian. Have you read the very good guidance on choosing a blade on his site. It says the M42 is very good for reclaimed timber. It also suggests that wider blades are not always the best choice if the machine can't tension it properly. It looks like the Startrite could.

When I first got my Record BS350, I was using a 3/4" 3TPI blade. Max for the saw.. The indicator on the saw showed it was tensioned OK, but it is very crude. It cut fine. The 3/4" blades came with the saw, One was new.

I now only use M42 1/2" 4tpi. They do last a long time and my saw can tension them better.

 

[rogxwhit]

I note that the wood is shown next to brick, gravel and cut glass - which reminded me that generally, one never knows what reclaimed wood has been in contact with - I recommend wire brushing all surfaces before sawing to dislodge embedded material.

With old pitch pine be prepared for considerable resin build-up on blades, bandwheels and other surfaces.

 

[deema]

Bandsaws are limited by either their back strength or the ability of the spring to tension a blade. If the back isn’t strong enough the machine will nod and potentially you can distort it permanently. It is however more likely that the spring arrangement is the limiting factor. Springs can only be compressed at a max to 25% of their relaxed state. If you exceed this they take a permanent set and no longer have the correct spring constant. Often bandsaws are over tensioned and the springs compress fully so that the coils are touching and no springiness exists, at this point the blade cannot flex and is likely to break…….but you have also destroyed your springs. So, typically bandsaws are actually unable to tension up the maximum blade width they specify (wonderful marketing people) it’s usually around a blade width one lower that they are really capable of handling. M42 needs a lot more tension, so a 1/2” M42 typically is the same tension as a 3/4” blade……that’s a bit tongue in cheek as it’s all to do with blade tension. Sideways started a thread on a a S45 bandsaw we refurbished in which I wrote about springs and blade tension and how to work it all out.

https://www.ukworkshop.co.uk/threads/scm-minimax-s45-bandsaw-teardown-overhaul.135069/
The last thing to be considered is the static loading capacity of the wheel bearings. If you go through the S45 thread I’ve given references for the SKF bearing dynamic load calculator. The life expectancy of a bearing rapidly decreases with increased load. You need to be very careful not to overload the bearings or, if increasing the tension capacity of the saw consider whether larger bearings will be needed.

For most things a correctly tensioned 1/2” blade is perfectly capable of ripping almost any thickness, it’s the tooth geometry that really determines the ultimate thickness. The wider the blade, the less prone it is to twisting if the user pushes the stuff through it too fast. Ie wider blades are good for when time is money, for hobby / careful conscientious users you can rip perfectly well with a 1/2” blade……it’s what I use!

In summary, I would not exceed the stated capacity of your saw unless you want to damage the springs. It’s highly likely the springs are already damaged and need replacing, things can be done to improve the capacity of the saw, but that usually requires modifying the saw tensioning system. A 1/2” blade with the right tooth geometry is perfectly capable of ripping the same thickness as say a 1” wide blade.

 

[toolsntat]

Thanks for the pointers folks.
I'll be looking to a 3tpi 1/2".
Cheers, Andy

 

[Alli]

Sorry, I know this is off topic but in that second photo, is that all the cuts needed to get quarter sawn timber? or was something else going on for all those cuts?

 

[toolsntat]

Sorry, I know this is off topic but in that second photo, is that all the cuts needed to get quarter sawn timber? or was something else going on for all those cuts?

I believe it's called Crown Cut and was/is required to match some original block flooring.
The face of these blocks need to have the outside radius of the growth rings in line with the surface.
The picture shows that effect and the (slightly darker) area under the cooker I previously did
Cheers, Andy

 

[TRITON]

You can get a 1.1 tpi rip blade.

 

[Alli]

I believe it's called Crown Cut and was/is required to match some original block flooring.
The face of these blocks need to have the outside radius of the growth rings in line with the surface.
The picture shows that effect and the (slightly darker) area under the cooker I previously did
Cheers, Andy

Doh! Crown cut not quarter sawn, I'll get there one day.

Your floor looks amazing, I'm sure that was a lot of work but certainly worth it. Thanks very much.