Thread: Bandsaw Blade Width Selection & Bandsaw bed throat and blade Alignment

Problem number one is a new one on me. Never heard that before, maybe it's some new thinking on the subject but I doubt it. If your tyres are slightly crowned, as mine are, then the gullets are clear of the rubber when the blade is centred well on the wheel. If you move it back or forth, by adjusting the camber of the top wheel, then it affects the angle that the blade presents at the table and hence the cutting direction. You can use that to adjust the tracking.

With your second problem, it's not clear from your description but it sounds as though you are referring to where the blade sits in relation to the front and back of the clearance slot in the table? If that's the case, how far back on the top wheel is the blade sitting, and how wide is the blade? I don't see any reason the blade needs to be centred in the hole because it will depend on the size of the blade. I certainly wouldn't be re-tapping holes etc unless it is a major issue.

I have found a 3/8" bi-metal 4 TPI skip tooth blade to be the most versatile and long-lasting blade I have used. I use mine largely for re-sawing but do cut the occasional shape with it. That blade will cut a reasonable radius.

I don't think your little bandsaw will drive a 34mm blade, even if you could fit it.

My bandsaw is a Hammer N4400 with 4HP motor and Maximum blade width is 27mm, with Hammer NSW recommending 19mm for ripping. I currently run a 19mm 3/4tpi Wood Slicer for re-saw and 10mm 6tpi for cutting turning bowl blanks.

I'd have a serious think about this as the Lennox blades are not cheap.

The advice given to me in Problem one fly's against every piece of information I have heard on bandsaws. If correct it would mean that everyone who uses a narrow blade on a bandsaw to cut curves is doing it wrong. Which is highly doubtful?

As for the second problem. I had another go at positioning the bed so that the blade sits in the center of the hole. In short I have been able to center the blade and secure the bed to the machine using two out of the four bolts, thanks to some play in the bolt holes. While not a perfect it has fixed the alignment issue. Now the blade is only 0.2 mm off the dead center of the hole.

I made this drawing to explains the second problem. The Green circle is the hole in the bed, the grey rectangle is the position of the blade (before my workaround), and the blue is the cast iron bed. SilentC the blade sits dead middle of the crown on the top wheel and its a 1/2" blade.


bandsaw.png

Originally Posted by Pat

I don't think your little bandsaw will drive a 34mm blade, even if you could fit it.

My bandsaw is a Hammer N4400 with 4HP motor and Maximum blade width is 27mm, with Hammer NSW recommending 19mm for ripping. I currently run a 19mm 3/4tpi Wood Slicer for re-saw and 10mm 6tpi for cutting turning bowl blanks.

I'd have a serious think about this as the Lennox blades are not cheap.

Pat you only confirm that the advice given to me is totally wrong. I will have to give them a call on Monday and nut out the details again. Yep the Lenox blade is costly at $190 for a carbide tip blade. However they come highly recommended and what I can tell the blade is one of the biggest factors in the performance of a bandsaw. Christopher Schwartz wrote:

I’d rather put a $200 blade on a solid used $300 band saw than a $7 blade on a $3,000 Laguna. The blade counts.

However having a $3,000 Laguna/Hammer with a $200 blade would be even better.

OK, well in that case the only thing it can be is the location of the table. It may have always been like that, may have a different table on it or the diameter of the wheels has increased by re-tyring or new wheels and the guides have been shifted across to compensate - but there's a limit to how far they will move without running into other problems. You didn't say how far out it was before you started? Was it as bad as your picture indicates?

Looks like an older saw, did you buy it second hand?

Helmut, you'd never be able to properly tension a 34mm blade on your saw.

Ive always used a 3/8" 3tpi skip tooth on mine and that is what you would've been using when you've ripped timber on it. I would strongly advise you to use either a 1/2" or 3/8" as those two would be the best to get good tension on the blade for ripping.

Yep its a second hand machine see this thread for my clean up and fitting of a single phase motor.

https://www.woodworkforums.com/f27/woodfast-bandsaw-buy-178564

I would not be surprised if the machine has had some work done to it. It was a school machine bought for the school in the 1960's when the school was setup and there it worked for 50 years before coming to me.

Yep the blade was that bad out of position before I adjusted the table. A good 6 mm off center.

Originally Posted by silentC

OK, well in that case the only thing it can be is the location of the table. It may have always been like that, may have a different table on it or the diameter of the wheels has increased by re-tyring or new wheels and the guides have been shifted across to compensate - but there's a limit to how far they will move without running into other problems. You didn't say how far out it was before you started? Was it as bad as your picture indicates?

Looks like an older saw, did you buy it second hand?

OK, well 6mm could be within the tolerances of the guides and the chassis of the machine if larger wheels or thicker tyres were added at some point in it's history. You'll probably never know. As for what to do about it, if you're happy with the two bolts I would leave it at that, unless there is scope to enlarge the holes in the mounting bracket.

SilentC Well the two bolts seems to be holding the bed secure so I am happy with the patch. Someday down the road if I do a full restore I will consider enlarging the holes.

I have sent the supplier an email outlining my concerns with their recommendations hopefully I hear from them soon.

DJ - Thanks for 3/8" recombination, I will bring it up with the sales rep.

SilentC, Pat and DJ seem to have given good advice.

Just to reiterate, Christopher Schwartz gave very good advice about blades. A great blade on an average machine is preferable to a poor to average blade on a great machine.

As for blade choice, it depends on the thickness of material you want to rip, but in any case 10 to 12 mm is likely to be OK.

I have a 1" TCT blade on my 14" saw and love it to death, despite the high price. This saw is used mostly for cutting veneers. In recent times the steels available for blades has improved and I have bought three 1" wide blades (all from different manufacturers) for my 14" saw. A couple of years ago that width was unthinkable on such a small saw.

Recently got a 1" TCT blade from Henry Bros that I have not yet tried. About $140 for a 25 mm wide TCT Lennox blade. Got it to put on the saw when the time comes for the other blade to be sharpened. Both the blade and the seller got very good reviews here.

The other thing you must consider is tension. I max out with a 19 mm blade on my old Trade Tools band saw because I can't put enough tension on a wider blade. However, sometimes you can retrofit a stronger spring that may give you some additional tension.

Have fun!

John

John the tension spring I think could do with a replacement. I quick search brought up Cobra Coil Bandsaw Tension Spring. But finding it locally that would be hard.

I would be happy with a 1" TCT blade. As I too would be mostly cutting veneers.

I had a look at removing the tension spring. Basically it will not be easy. I will take some photos tomorrow and maybe someone can help me figure out how to strip down the cast iron housing for the tension spring. That is connected to the top wheel, as far I can figure I need to remove the wheel so that the housing comes apart. But how to do that, I am clueless.

Originally Posted by thumbsucker

I had a look at removing the tension spring. Basically it will not be easy. I will take some photos tomorrow and maybe someone can help me figure out how to strip down the cast iron housing for the tension spring. That is connected to the top wheel, as far I can figure I need to remove the wheel so that the housing comes apart. But how to do that, I am clueless.

It is likely that you can successfully tension a 3/4" blade. Even my old Trade Tools saw will do that. A 3/4" TCT blade will likely do a very good job for you, depending on your maximum depth of cut. My saw has a max depth of cut of 355 mm, so a 1" blade with the attendant beam strength is a good idea. However, most of these machines have a max depth of cut of around 250 mm. It seems likely that for that depth a 3/4" TCT ripping/veneering blade would do a very good job for less money than the wider blade.

Cheerio!

John

Originally Posted by John Samuel

It is likely that you can successfully tension a 3/4" blade. Even my old Trade Tools saw will do that. A 3/4" TCT blade will likely do a very good job for you, depending on your maximum depth of cut. My saw has a max depth of cut of 355 mm, so a 1" blade with the attendant beam strength is a good idea. However, most of these machines have a max depth of cut of around 250 mm.

John my machine has max depth of cut of just shy of 180 mm. Does this mean that this further limits my choice for blade width?

Replacing the Tension Spring

I feel that the tension spring is one thing that should be replaced even if I will use narrow width blades 1/2" - 3/4". Since the spring is from the 1960's and is well over 50 years old, it makes sense that it is no longer in even good condition and should be replaced at this point of the bandsaw restoration.

I had a go at dismantling the housing but could not figure out how to access the spring.

Photo 01

The spring is housed in this cast iron box, the box is secured to the bandsaw frame via two very long 10" bolts. Removing this part was simple. However these two 10" bolts hold the tension housing / mechanism, the top part of the sheet metal casing and the top wheel to the bandsaw frame in place.

01.jpg

Photo 02

Show Left top Right - the top wheel, the sheet metal casing & the housing for the tension adjustment housing.

02.jpg

Photo 03

Two small bolts that secure the sheet metal casing to the bandsaw frame.

03.jpg04.jpg

Photo 04

From my examination it seems that the Arbour runs from the wheel as show in Photo 04 through the sheet metal casing and into the tension housing mechanism. It is impossible to access the spring in the housing without removing the wheel first. There is a small U shaped clip resounding the end of Arbour of the wheel I managed to remove this however how to go from that point I have no clue.

05.jpg

Therefore my question is - How do I remove the top wheel? Please be specific as I am a complete novice when it comes to machines and anything mechanical.