Bandsawn dovetails

[MDE]

I've been using a bandsaw to cut dovetails successfully for some time. I've noticed that some blades cut straighter and smoother than others. In straight-grained light timber it is never much of a problem. However, I have some hard and twisty fiddleback sycamore which even my best blade struggles to cut exactly straight, so I have to make allowances. Does anyone have any experiences or advice to share (other than sharp is good!)?
Thanks.

 

[Beau]

Sharp blade and close set guides above and below and all should be good.

 

[memzey]

The width of the blade makes a difference in that wider blades are more likely to track straight than shorter ones. I have a suspicion as well that once a blade has been used for cutting curves, especially tight radius curves, they never track quite as straight as before.

 

[MDE]

Sharp blade and close set guides above and below and all should be good.

Certainly agree with that.

The width of the blade makes a difference in that wider blades are more likely to track straight than shorter ones. I have a suspicion as well that once a blade has been used for cutting curves, especially tight radius curves, they never track quite as straight as before.

Normally I use a 1/2" 6tpi blade. I was wondering about going up to 10tpi. If instead I go to 5/8", then 6tpi seems to be the max. Also I am currently using the Tuffsaws "premium" blade as it is supposed to be thinner (so I thought it would be better for my "skinny pins"); however the actual kerf seems to be not much different from the normal blade, so perhaps it is only the blade body which is thinner. Arguably, the thinner blade ought to tension better though? My other thought is whether to use an M42 on the grounds that it will stay sharp longer.
The point about cutting curves had not occurred to me - I'll keep an eye on that one.

 

[Phil Pascoe]

"however the actual kerf seems to be not much different from the normal blade, so perhaps it is only the blade body which is thinner."

Yes, it's the width of the blade. There is is less to stick, and it follows a curve easier. The blade will be easier to tighten. An M42 will stay sharp for a lot longer, but like carbon tools as opposed to HSS the carbon steel will be sharper when new. Try a blade with fewer teeth rather than more? Ask Tuffsaws.

 

[Steve Maskery]

This will probably put the cat amongst the pigeons, but when I cut DTs on the bandsaw I use a 1/16" blade with lots of teeth. Like a dovetail saw, actually. Yes I know that much of the cutting is virtually ripping, but the DTs I cut are usually in quite thin stock so a normal rip blade would be too coarse anyway.
The narrow blade means that I can saw out the bottoms, between the pins and the tails, which is quicker and cleaner than chopping them.

 

[Myfordman]

The width of the blade makes a difference in that wider blades are more likely to track straight than shorter ones. I have a suspicion as well that once a blade has been used for cutting curves, especially tight radius curves, they never track quite as straight as before.

+10 It only take a tiny bit more wear on one side than the other caused by cutting curves to increase the probability of drift.
Segregate blades into New, Used only for straight cuts and General purpose-used for curved cuts.

 

[MDE]

This will probably put the cat amongst the pigeons, but when I cut DTs on the bandsaw I use a 1/16" blade with lots of teeth. Like a dovetail saw, actually. Yes I know that much of the cutting is virtually ripping, but the DTs I cut are usually in quite thin stock so a normal rip blade would be too coarse anyway.
The narrow blade means that I can saw out the bottoms, between the pins and the tails, which is quicker and cleaner than chopping them.

Or is that a tiger amongst the doves?
1/16" - do you mean that? It sounds incredibly small for a bandsaw and 1/8" seems to be the general minimum.

 

[Steve Maskery]

Yes I do mean that. They are not easy to come by, not least because of the difficulty of welding them. I have 3 left, which I bought many, many years ago from Hamilton Edge. I look after them and don't use them for anything else. They do a superb job.

One of the difficulties of using such narrow blades is that of supporting them. There is so little body behind the teeth that you can't do it in the conventional way. I get round it by facing my steel guide bearing with a disk of 2mm MDF, held on with DS tape. The guides touch the blade, but as they are MDF, the teeth are not damaged, they cut their own furrow and then are supported for their entire 1/16" width.
I've not used them for a while, I must cut some DTs again one day soon.