Cutting blanks on bandsaw

[bogmonster]

Hi,

At last I have a bandsaw. Paid a bit over the going rate but was fed up messing about. It's a vintage Startrite 352. I have not used a bandsaw before so just learning the basics. Main use will be cutting blanks in green wood for faceplate bowls. I have some of TuffSaws blades and the 3/8ths 3tpi wide set blade is working fine and dandy. I also have a 3/4 for straight cuts. I picked the saw up this morning and this afternoon played. I know have a pile of blanks in both labernum, sycamore and holly. The thickest wood I cut was the laburnum that just fitted under the guides (without removing the guard). Slow and steady feed - no issues.

Anyway, to the point of the post, I have done some research and still not sure how best to cut circles. My gut feel is that free hand without a jig will be best. That works fine where you have a piece of wood with parallel faces but wanting to get the most from the wood I tend to split down the pith and will end up with the varying height of the outer circumference (bark). I put the flat surface of the split log on the saw table but my issue is how to mark a circle on the massively uneven surface? If I just use dividers then I would end up with an oval. On mu first try I screwed a piece of round ply onto the top surface and just kept wide of that but I don't like that solution.

I am not that keen on a jig so wanted to know if there is an easy way to mark the blank circumference on the curved surface.

Apologies if this a really dumb question,

BM.

 

[paulm]

Using a circle of ply is the way I do it BM, I keep a set of them in different diameters and fasten them in situ with a woodscrew then cut round them by eye.

It doesn't need to be a very precise operation, the blanks will move as they dry out anyway and become slightly oval, all you are doing is getting them somewhere near in balance and reducing time spent at the lathe bringing them into round.

Rough them out to roundish on the bandsaw, seal the edges and stack somewhere to dry out, and then enjoy turning them

Cheers, Paul

 

[bogmonster]

Paul, I think maybe you are right. Ply circles it will be. Blanks are in the kiln at the moment which is at 98 degrees humidity. I will rough the thicker ones on the lathe because they will take an age to dry otherwise. I think I will wax seal the thinner ones as I have a bit of a glut of timber at the moment (yes, nice problem to have).

Totally impressed with the bandsaw though. I think it will speed up the process massively. Next project is a tungsten carbide roughing tool to speed up wood removal. My lathe is a bit gutless so not really sure how well it will work but I am going to try the Easy Wood style cutters on a home grown shaft and handle.

BM

 

[dickm]

Ah, another fully paid up member of the 352 fan club!

 

[bogmonster]

I did try the Startrite circle cutting attachment (I had to make a new one as the original was missing) but didn't get on with it. I wonder if another solution is a laser pointer to the center of the blank and then just keep the dot centered. I might see if I can make up a bracket and give that a go.

BM

 

[CHJ]

I've just got a stack of hardboard discs ranging from 70mm to 230mm and do the same as Paul, (but I just use a small nail/pin to tack them on)

I have an accurate circle cutting jig I made in the early days that fits in the table key way but it only gets used about once a year now.

 

[CHJ]

I have some of TuffSaws blades and the 3/8ths 3tpi wide set blade is working fine and dandy. I also have a 3/4 for straight cuts. .

I think once you get into regular use on the saw you will find there is little need for anything other than the 3/8 X 3tpi for turning associated work, I regularly slice logs into 20-30mm slabs with one and the wider blades are still sitting in the store cupboard.

Even relatively thin sections are no problem.

 

[chipmunk]

Can I ask a clarification question to Chas and Paul...

Even with the tacked on circles do you chaps aim to cut full circular blanks on the bandsaw or do you just knock the corners off to create octagons?

I must admit to being reluctant to gratuitously cut curves with my bandsaw when straight cuts will do. I know I could cut blanks alternate ways but I'd still like my saw to cut straight afterwards - like I can see Chas' does.

Many thanks
Jon

 

[paulm]

Hi Jon, I cut the curved outline rather than using straight cuts to cut bits off, reason being it annoys my marginal OCD if the blanks aren't round :lol: Apart from that it saves a little bit of time at the lathe and generally makes the blanks a little bit more balanced to start with.

I don't really tend to notice a reduced ability to cut straight with the blades after doing curves, but then I am generally not forcing a blade round a curve that is too tight for the blade depth, instead I allow the blade to cut the curve within the width of the kerf created by the teeth. Or in other words, use narrower depth blades for smaller, tighter curves rather than wider blades. As Chas says, a 3/8" width is good for a lot of stuff as a general purpose size.

That's not to say that a blades straight line cutting performance doesn't reduce over time if cutting lots of curves, just that if you are sensible with how you cut the curves and don't force a blade to cut a smaller curve than it comfortably can, then the loss of straight cutting performance may not be noticable for many situations.

Having said that, if I have an accurate/important straight cutting job to do, then I may well put a fresh blade on just to be sure, but for lots of rough cutting or sizing I wouldn't bother.

Tend to find that losing sharpness on a blade happens before I start to notice issues with straight cutting, so just treat the blades as consumables, they do need replacing after repeated use whether straight cutting or curve cutting.

Not sure if any of that makes sense or I am rambling incoherently, haven't had the morning coffee yet :lol:

Cheers, Paul

 

[CHJ]

The super tuff blades from Ian have increased set on the teeth and are extreemly hard waring, as Paul says as long as the blade kerf is wide enough to accomodate the blade width in any curved cut then I never have any 'curved versus straight' isses with a blade.

This is the same blade as seen above cutting slices.

21-22/10/2012
as this

13/10/2013 and I have cut litterally hundreds of round blanks with it during that period, both green and kiln dried ranging from 80mm x 25 to 250mm X 200.

There's some small ones cut on the 17/10 that can be seen at the bottom right of this picture.

 

[chipmunk]

Not sure if any of that makes sense or I am rambling incoherently, haven't had the morning coffee yet :lol

No, that's very useful Paul - Thanks and Thanks Chas.

I suppose it's horses for courses. I may try cutting full rounds next time and see if it makes any difference.

My blanks tend to be cut from half-logs, rather than from boards, and so in-balance may be a relative term :wink:

I like to use M42 1/2" 3TPI blades from Tuffsaws which are obviously consumable but do last quite a long time before they get blunt. I'm not sure they have that much set on them :?

Jon

 

[CHJ]

I regularly cut blanks from large logs, both green and partially dried, you can see some typical stock in this shot.

I too have M42 blades but they have stayed in the store ever since Ian started supplying the wider kerf supertuff blades.
Yes M42 cut nails etc. but I try to avoid those with a detector check on logs but they don't have the wider kerf that is so much better for saw dust clearance in green wood and curved pieces.

 

[chipmunk]

Thanks Chas.
I may have to try a supertuff blade too then, although to be honest I've had no real problem with my M42 blades binding in green wood so far...

...but then I don't cut curves, do I? :wink:

Jon

 

[bogmonster]

Thanks for all the help.

Well, I don't have much to compare with but the 3 TPI sabrecut is working well for me. I will be keeping the 3/8ths fitted most of the time I am sure. I did split some big logs with that blade and was pleasantly surprised with how well it worked for these cuts as well as cutting the rounds. Swapping blades to split logs and then round is too time consuming. I can't compare with the M42 but happy with what I am using so will stick with it. I did get some blades with the saw but not too sure which they are. I think they came from TuffSaws as well.

What kind of life can I expect from the sabrecut blades? I would be happy with 50 reasonably sized blanks.

I am definately all for cutting rounds, not polygons. Done the polygons for a couple of years with the chainsaw and that's been quite enough......thump.....thump.....thump.....thump.....

A couple of added bonusses of the bandsaw for me are less shavings and more reasonably sized offcuts for the log burner. Also, I cut some blanks in wood that otherwise I may have discarded. Being able to easily cut into the wood and inspect for splits and the like will mean better wood utilization. Also, splitting a half log again into say 2 or 3 inch thick blanks is something that's not easy with a chainsaw so I tended not to bother and turned thicker bowls or just created a lot of shavings for a thinner bowl. With the bandsaw I can maybe get a couple of thinner blanks if I want.

I must get a metal detector - I think there something called a Lttle Wizard or something like that - time for Google....

 

[chipmunk]

Hi bogmonster,
I hope you don't mind me making a suggestion, admittedly after interpretting your last post...

Instead of a thump.....thump.....thump.....thump..... which implies to me an interrupted cut around the edge of the blank, have you tried a pull cut around the corner from the front face with a swept back grind or a push cut from the front cutting through the
unevenness?

I don't like many of his ideas, including the gloved left hand and his insistence on faceplates, but Lyle Jamieson is doing things this way here with a square blank...

http://www.youtube.com/watch?v=X06EjQhDROk

...just a suggestion.

The polygon shaped blank doesn't need to be a trial.
HTH
Jon

 

[CHJ]

.....What kind of life can I expect from the sabrecut blades? I would be happy with 50 reasonably sized blanks. ......

Not saying it's typical as there are so many variables and there is aways a risk of unexpected kinks in the blade etc. but Look carefully at the dates in this post

 

[bogmonster]

Ah, I had missed the fact that you had cut hundreds with the SAME blade If I get anywhere close to that I will be more than happy. I will need to brush up on my reading skills.......

 

[blackrodd]

I use an offcut of ply and draw the blank size circle with a compass and drive in a panel pin at the centre, cut it off so about 1 or 2mm is showing and flle to a point. pencil a cut line to the edge of the circle.and slightly beyond so the blank is clear of the saw when it's cut for safe removal!
As long as you cover the pencil circle with the blank, just rotate the blank on the point.
I hope this makes sense. Regards Rodders

 

[sammo]

I use cardboard - cut into a circle; simple & cheap. Pin it to the wood then cut around; as in previous posts you don't have to be spot on, just get it approximate!