Thread: Bandsaw sharpening

Looks good, like the idea of using an existing product with minimal modifications to do an excellent job.
Kryn

Definitely can't argue with the price

It looks like a variable pitch blade?
BSBSBand.jpg
Based on the wheel being 100mm, I get photoshop measurements of 2.5 - 4 TPI
Of is this your practice band?

What about set?
It looks like quite a wide band so it will be capable of many sharpenings but sooner or later it will lose its set.
In fact just using a BS band in hard wood can be enough to remove set.

If multiple sharpening are done without adjusting the set, adding the set after multiple sharpening requires more tooth bending and can break teeth so its better to add some set after every sharpen or at least after every few touch ups. If you have to add a large amount of set it's better to add it incrementally.
It can be done manually with a handsaw tooth setter, but just be care not to force a tooth the other way.

I'm yet to do any sharpening with it Bob. This is the one i gave the lightest of touch ups with the multitool belt a couple of months ago. I need to work out what the variation is in pitch before us the attachment on it. I'm more interested in putting it to the test on my Resaw King carbide tooth blade. Just have to hunt down a diamond grinding wheel for that. I'll keep posting updates ad i go.
cheers

Suggestion, An flippable/ratcheting adjustable height stop or band gripper at the BS table top level could be swung in and out to provide a registration point for the blade.

Sequence
Grinder out
Move blade up so it flips/ratches past stop
Move band down so it goes up hard against stop
Grinder in

REPEAT

This will require a constant pitch band to work properly.
It might require a couple of passes to seat things in.

Originally Posted by BobL

Suggestion, An flippable/ratcheting adjustable height stop or band gripper at the BS table top level could be swung in and out to provide a registration point for the blade.

Check this out - it's been done:

Originally Posted by RossM

Check this out - it's been done:

Yep that's it.
Most auto and semi auto sharpening systems use this ratchet-pawl approach.

I'd be into this like a rat up a drainpipe but I have access to an auto band sharpener for my lower TPI bands.

Great idea but I'd have thought the down facing edge of the tooth is what is sharpened. He's sharpening the trailing edge of the tooth. Why is that?

Read my earlier posts, Sheddie. That will show you what is involved with sharpening a bandsaw blade - without touching the gullets.

Regards from Perth

Derek

Hi Derek, i did read it again but i still don't understand why only non cutting edge gets sharpened. The trailing edge of the tooth doesn't cut??? Surely its the cutting edge - the leading edge - that should be touched up. If not, then how does sharpening the non cutting edge of a carbide toothed blade cut better if the Carbide isn't touched up. Am i missing something here???
cheers
mike

Originally Posted by Shedhand

Hi Derek, i did read it again but i still don't understand why only non cutting edge gets sharpened. The trailing edge of the tooth doesn't cut??? Surely its the cutting edge - the leading edge - that should be touched up. If not, then how does sharpening the non cutting edge of a carbide toothed blade cut better if the Carbide isn't touched up. Am i missing something here???
cheers
mike

Only the pointy end of Bandsaw teeth needs to be sharp for a BS band to cut wood and this can be done from either side of the tooth.
While the other edges don't need to be sharp for it to cut, it does help (see below)

When ripping, the point is continually cutting close to 90º across fibres, so the point does all the work
When cross cutting the point goes in between the fibres and actually tears out the wood rather than cutting - all that is needed is a sharp point.

The reason for having a clean band and sharp edges is to help tear the chips out.
If these edges are gummed up or rounded the tearing will produced more longer fluffy ended torn out fibres so there will be more friction and this will not help the cutting process.
If the teeth are not eventually reset the cut will become narrower and will further add to these problems
If only the tops of the teeth are touched up eventually the gullet will also become too small then they will not carry enough sawdust and slow the cutting.

For really efficient high speed cutting it is beneficial to camber both the point and side of the gullet just below the tooth.
This improves penetration and chip tear out and leads to less loss of set.
This makes very little difference on small bandsaws which operate at slow speeds but it makes a significant difference on large higher speed saw milling operations

If you are doing light whisker touch ups like Derek, unless you are cutting very wide boards on a regular basis you wont notice these issues for some time.

Mike. Bob has explained part of it.

What needs to be added is that the gullet is important to retain since this is involved in clearing the saw dust. In addition, the rake of the teeth must not be altered since this will affect the way the tooth cuts. Touching up the back of the tooth effectively removed the wear bevel and re-sharpens the tooth ... without touching the gullet. The danger of your machine is that you will alter the rake, and this will affect the way the blade cuts.

I touch up a blade 3, sometimes 4, times before declaring it beyond salvage. I do not touch the gullet and I do not touch the set. A little less set will, in fact, make the cut smoother.

I would try the method I outlined before you mess further with yours. It is quick.

Regards from Perth

Derek

Thanks for the info fellas. Ive decided its just as easy to sit down at the BS and touch up the blades with the dremel. I picked up a pack of 2 chainsaw sharpening stones for the Dremel this arvo. It only takes 10 or 15 minutes to d o it an the results are impressive.
i still have to find out how i touch up the carbide toothed resaw blade however. Some tips on that would be appreciated.
cheers
Mike

Carbatec sell a small diamond coated disc that could be used on TC teeth.

https://www.carbatec.com.au/sharpeni...-wheel-diamond

The industrial profilers such as BobL mentioned sharpen the face of the tooth and also the gullet. The reason the gullet is sharpened is two fold. As the tooth is sharpened the height of the tooth decreases very slightly which in turn lessens the depth of the gullet and consequently the capacity of the gullet and the ability to carry away sawdust.

Secondly there is the potential for stress cracks to develop in the gullet. Taking a minute shaving off the gullet removes this potential. The profiler if set up correctly will perform this operation at one hit. Incidentally the grinding disc, which comes with a square edge rather like an angle grinder grinding disc, has to be shaped with a gentle curve on the lower edge and a tight radius on the upper edge.

These profilers are probably only suitable for larger tooth patterns. I am not sure what they will sharpen down to. They are also very expensive even for the most simple manual versions.

Many bandsaw blades can only be sharpened a few times as the hardened part of the tooth does not extend very far. In the end I think you have to say sharpen until it no longer works. Probably the blade will break before you reach that point.

This is something I turned up the other day from the Simonds Saw Company

http://www.simondsint.com/woodbandsa...%20version.pdf

I found it very useful, but you do have to remember it is produced by a company with a vested interest. It is also true to say that they have had this vested interest since 1876 and are the only one out of the three major American saw manufacturers to still be in business (Disston and Atkins being the other two).

Regards
Paul