Carbide tipped bandsaw blade setup: aaagh!!

[Bojam]

Afternoon all,

I have a new 17in bandsaw. The spec says it can accommodate blades up to 32mm wide. It was supplied with a 30mm carbon steel blade which I have never used.

I bought a number of M42 (bimetal) blades of different widths and configurations from Ian at Tuffsaws and have been running these from day 1. The largest is a 20mm 3TPI blade that I use for resawing. I've been able to set this up (tension, tracking, guide bearings, etc.) to run straight and give nice even cuts. Obviously, since it's quite a coarse blade there is a bit of cleaning up to do, but I can resaw boards and achieve consistent thickness cuts without experiencing any drift or barrelling.

I also bought a carbide tipped blade specifically for clean cut resaw work. It's the 20mm wide X-Cut blade from a German company called Bandsaegenprofis. Made of Swedish steel band (0.6mm thickness) with a thin kerf (~1.5mm) and variable tooth pattern (12-14-16 pitch, 2-3TPI?). It's pretty similar to the Laguna Resaw King blade.

I fitted this blade for the first time yesterday and went through the usual process of tensioning and tracking then setting up the guide bearings. But no matter what I try I get a lead into the cut (i.e. the blade/cut line drifts away from the fence) and the blade continues to wander down the length of the board. So I get boards of inconsistent thickness (though not barrelled).

I'm struggling to understand what's going on here??

The 20mm M42 blade from Tuffsaws is ~0.8mm thick and I tension it to 7 on the tension scale (which runs from 0-10) and get good results. I've tried tensioning the carbide tipped blade at the same tension and at increments right up to close to the max. This doesn't seem to have any effect. I know these blades require considerable tension but the manufacturer advised me that a 20mm blade on my saw would be fine and I know of other people using similar saws with 3/4in carbide tipped blades and seem to be happy with the results. I've also tried tracking the blade further back and further forward but again, no noticable effect. I wondered about wheel alignment but since I can get good results with the M42 blades with the wheels in the factory set position I'm reluctant to mess about with this. I also can't put a straightedge up to check the alignment as the frame/casing sticks out beyond the wheel position.

I should add that I work with tropical hardwoods (much of it reclaimed) hence the choice of durable M42 for all my blades as standard. I was hoping the carbide tipped blade would allow me to resaw with cleaner results. Frustrated that I can't get it work (expecially since it cost about 100 Euros!)

Suggestions would be gratefully received as I've given up for now and refitted the M42 blade to get on with some work.

Thanks in advance (and apologies for the long post)!

 

[clogs]

Bojam,
I think the answer to ur problem is the grind on the tips......
Is it poss that u can re adjust the fence to match the drift on the tipped blade.....?
I also use Tuff Saws for my blades, well untill my stock is gone......but it's poss that the same blade made from a fresh roll of blade material will be/cut different to ur original....or from a dif manufacturer...say Bacho.....
as an example...
if a HSS blade has touched one of the bearing guides etc hence dulling the teeth on one side of the blade it will also cut out of true.....this is just an example to help describe a similar prob....

 

[Bojam]

Bojam,
I think the answer to ur problem is the grind on the tips......
Is it poss that u can re adjust the fence to match the drift on the tipped blade.....?

Hi Clogs

Thanks for the reply. Is it normal to have to do this? I guess I can play around with the fence to see if I can realign it but I don't really understand why that would be necessary with this blade in particular but not with the M42 blades (where the fence is set parallel with the mitre slot and blade). Seems like a work around rather than a fix but as a relative bandsaw novice I don't know whether this is to be expected?

Also, the cuts always start off by leading away from the fence but then the blade wanders so how to align for a path that deviates like this along the board?

Cheers.

 

[MARK.B.]

It's Possible you have a duff blade, have you tried putting the old blade back on to see if it cuts ok ? if it does then put your new one back on and try again,if still no joy then you may just have a bad blade or that that type/make of blade is just not suited to your machine.

 

[Ttrees]

Likely the blade is under tensioned, but whether that is the real issue is another matter.
You won't find much info about carbide blades (that I know of) in the UK.
You would be better off looking at John TenEyck's blog or posts from the "creek"
Guessing it might be the closest thing to your machine,
i.e 17" grizz machine (albeit heavy duty) with crowned tires.
There's not many folks using these blades on smaller machines.

Seems from some reading, you stand chance of compressing the spring.
Don't listen to any manufacturer about capability, same goes for the gauge.
These carbide blades need greater tension than regular blades.
John got the recommendation somewhere (maybe Lennox site?)
that these should be tensioned to 25000 PSI.
I can tell ya it's likely to be off the scale by a lot.

Since you have a blade which is very expensive, and if you think it's running good
stationary, then you might be keen to try and get use out of it.


You could make a block for your straight edge to clear the frame. Probably don't even need to take off the guide post/cover.

NOTE if doing this then take measurements first, and DONT do any adjusting with a TIGHT BELT!, as
if it's misaligned somehow with the motor, then it can mangle motor bearings in all of five seconds.
Looose belts are kinder on things.
Easy to line the eye up with the pulley to see if things are coplanar.
Should run nice and smooth without blade, no vibration.

Top wheel stuff like what I'm doing now, does it move or make any noise without any blade on?
Tires, any inconsistent witness marking?

Have to go, will edit my post later.

That should keep you busy for now, lol
Good luck

 

[Bojam]

It's Possible you have a duff blade, have you tried putting the old blade back on to see if it cuts ok ? if it does then put your new one back on and try again,if still no joy then you may just have a bad blade or that that type/make of blade is just not suited to your machine.

Yeah, put the 20mm M42 Tuffsaws blade back on, tracked and tensioned it and it works just as before - straight clean cuts. I will have another look at the carbide blade at some point but short of ideas on what to try that's different than before.

How could it be a duff blade? Not well sharpened for instance?

I know of other guys in France who have essentially the same Holzprofi saw as mine just 480mm rather than 430mm diameter flywheels. I'm assured that the rest of the build is identical, mine is just a little smaller. They run 25mm (one inch) carbide toothed blades on their saws with apparently good results. I've asked on the French forum for advice and awaiting a response. Would be disappointing to have wasted ~100 Euros on a lemon!

 

[Bojam]

Have to go, will edit my post later.
That should keep you busy for now, lol
Good luck

Hi Tom, thanks for the detailed response. I'll reply properly later once the kids are in bed

 

[Ttrees]

A tell tale sign of something wrong is spelching from the bottom of the work,
I've found the tires play an important part to this.
Flat tires being more temperamental/obvious, but possibly the same could be said for running such a wide blade on cambered tires, (john's machine for example)
as in that things will only start to show up then, compared to running narrow blades which can find a spot even if things are sub optimal.


I can tell you if you're getting bad results/drifting and a suitable blade is still sharp, then
a possible cause for this is misalignment/tires causing the blade set to compress.
Yea, that might seem obvious, but how many folks have short fences on their bandsaws?


Another issue if the blade is walking fore and aft, but it's known to be good, the alignment also checked, and also the tires, then you could look into the top wheel issues.
Lock the tracking adjustment bolt, and give that top wheel a tug.
There's a large chance that the carbide tipped blade is too much for the saw.
Something could be giving up, or deforming inside the saw whilst tensioned.
I've read it suggested that wheel alignment is done using the maximum blade for the machine.
If nothing found to be an issue there,
Apart from that, it could be issue with bearing spacers, which I am making at the moment.
I wouldn't be surprised if that were the case, should it be the same job as this with an non shouldered bore.
About 1mm play between bearing and spring retaining clip, quite hard to notice on the machine.

Eager to see how things go, and to give the saw some "dynamic testing"
i.e...using the bloomin thing!
Reckon I've got near any fluttering done away with, regardless of tension, which wasn't the case before.
Another wee hint or thing to take note of, along with listening to the wheel without blade installed, or any groaning from the blade when installed, any rubber deposits, you could see that with some biro to check.

Hope that helps, it's just about all I can tell you....so far!

Tom

 

[Jar944]

The 16" saws are at the practical limit for carbide, and most (including some german made saws won't tension to 25k)

I would try it with the tension as high as you can fo on the saw and see if it helps the cut.

 

[Bojam]

The 16" saws are at the practical limit for carbide, and most (including some german made saws won't tension to 25k)

I would try it with the tension as high as you can fo on the saw and see if it helps the cut.

Yeah will try that. Have had it close to the max but not right to the limit. What I don’t understand is why these carbide toothed blades require so much tension?

I run a 20mm wide M42 blade without any issues and not close to full tension. Yet the M42 blade is 0.8mm thick compared to the 0.6mm thick band of the carbide tooth blade. I must be missing something because that to me would suggest the M42 blade (which is the same width as the problematic carbide blade) would require more tension?

 

[Bojam]

I run a 20mm wide M42 blade without any issues and not close to full tension. Yet the M42 blade is 0.8mm thick compared to the 0.6mm thick band of the carbide tooth blade. I must be missing something because that to me would suggest the M42 blade (which is the same width as the problematic carbide blade) would require more tension?

One difference is that the M42 blade is a regular 3TPI whereas the carbide blade is vari-tooth (12/14/16mm pitch). Does tooth geometry effect the amount of tension required?

The Laguna Resaw King blade is available in 20mm with the same vari tooth pattern. I’m sure people run that blade on small ~16” saws. It has a thinner kerf but the band is the same thickness as the blade I have I think.

 

[deema]

Large resaws typically don’t have tyres, the high tensions can cause the tyre to distort under the blade which will not be consistent around the perimeter. The distortion causes the blade to flex. One check I would try, is if possibly set it up without the tyres on the wheels.

 

[MARK.B.]

By Duff I was meaning a possible twist/kink or a poor weld/wonky teeth and such like , the sort that the QC department have missed and may not be immediately obvious to you on quick inspection.,

 

[Jar944]

Yeah will try that. Have had it close to the max but not right to the limit. What I don’t understand is why these carbide toothed blades require so much tension?

I run a 20mm wide M42 blade without any issues and not close to full tension. Yet the M42 blade is 0.8mm thick compared to the 0.6mm thick band of the carbide tooth blade. I must be missing something because that to me would suggest the M42 blade (which is the same width as the problematic carbide blade) would require more tension?

You may have a bad band?

This is the finish I get with a Lennox woodmaster CT 1.3tpi (1" blade on a 21" saw. )

 

[Derek Cohen (Perth Oz)]

I have a Hammer N4400, which has 17 1/2” wheels and a sturdy steel frame. For the past 6 years i have used a 1” Lenox Woodmaster CT blade for resawing. These are thicker and stiffer blades than bimetal, which I use for general cutting. The Hammer barely tensions the Lenox sufficiently. I simply cannot imagine that you are getting anywhere near the correct tension on your carbide blade when it is 7/10. Go up to 11!

Regards from Perth

Derek

 

[Bojam]

I have a Hammer N4400, which has 17 1/2” wheels and a sturdy steel frame. For the past 6 years i have used a 1” Lenox Woodmaster CT blade for resawing. These are thicker and stiffer blades than bimetal, which I use for general cutting. The Hammer barely tensions the Lenox sufficiently. I simply cannot imagine that you are getting anywhere near the correct tension on your carbide blade when it is 7/10. Go up to 11!

Regards from Perth

Derek

Thanks Derek. I’ll try it on the max tension and see if that improves things. Was reluctant to do so for fear of over-tensioning and potentially damaging the blade or worse the saw frame.

Bit surprised because the M42 blade feels stiffer (and actually has a thicker gauge) yet tensions well at 7/10 on the scale and gives a nice cut. Both blades as only 3/4in wide (20mm) so well within the capacity of the wheels.

 

[Bojam]

You may have a bad band?

Possibly. The weld looks clean and no obvious defects. Anything in particular to check for?

 

[the great waldo]

I got a laguna resaw king and then found the German supplier and got both I've only tried the German blade so far and it cuts 8 " hard maple very easily but as you have found it pulls to one side. I have had sucess using a kreg resaw fence guide the 7" one with a curve in the face and just follow a pencil line wihich works fine but is a bit of a pain to use. My previous blades swere 3tpi swedish Harkaansaw blades which tracked well. I'll try the Laguna blade sometime to see if it tracks better. I think the blade sitting on the wheel influences the drift, so when I get a chance i'll try different settings. I'm using an old Sartrite 352 with 14" wheels. It's fairly old now but have found the carbide blades resaw more easily than the Swedish blades which tend to trip the motor on deep cuts in hardwoods like rosewood. the blade i'm using 3/4" and I tension it by ear., If it makes odd noises I loosen or tighten till it sounds right. By the way I have a feeling that the German blade is made from the same stock as the Laguna blade looking at them both next to each other.
Cheers
Andrew

 

[clogs]

Bojam,
u have to look at that carbide blade as almost hand made....not quite but almost.....
although most of the work is done by machine there are a lot of variables....
Like everyone says as long as the bearings, wheel n tyres are good just run with it....
also Carbide is not really sharp as in Hss blades...on a micro level they tear rather than sever the fibres.....needing more tension and power.....
look at metal lathe work....which is/can be extreme....
the carbide tips are only happy cutting at high RPM under extreme loads with no coolant.....
I mean the chips come off BLUE.....
again just move the fence to suit the blade cut........
u cannot compare the HSS blade to the carbide although they do the same job......
I have to cut lots of knotty pine boards.....I could use a HSS blade but it wont last so I suffer a poorer finish by using a Carbide ttipped blade....
It's all a compromise.....if money and room were no object problem I buy anther bandsaw just for the resaw use.....but thats getting outta hand now.......
say he who has at least 10 pillar drills, 2 p/thicknessers, 2 spindle moulders and 2 lathes, and the list goes on...plus a very understanding wife......hahaha....
PM sent....

 

[Jar944]

I have to cut lots of knotty pine boards.....I could use a HSS blade but it wont last so I suffer a poorer finish by using a Carbide ttipped blade....

It's interesting you have lower surface finishes with carbide. I've not had the same results. For me carbide cuts faster and leaves a better finish than spring steel ot bimetal blades.