Page 1 of 2

Bandsaw bowl preparation

PostPosted: Fri Mar 20, 2009 4:24 pm
by Morten
Hello again

I was wondering, since I have a bandsaw, but no chainsaw; does anone have tips for preparing a bowl blank on the bandsaw?

Re: Bandsaw bowl preparation

PostPosted: Fri Mar 20, 2009 6:35 pm
by gavin
I have struggled with this too. I have gone back to axing much of the time. The difficulty is that you need a flat face on both sides of your work if you are going to bandsaw. The bottom face must be flat and firm on the bandsaw table, and the top face needs to be flat for your compass' scribe. I have experimented with screwing a plywood disc on the upper face (when that is curved) to give me a sight line to steer the bandsaw blade, but have not been very happy with that result.
I have a 3/4 inch blade on the saw and the makers assert that will go round a 10 inch circle. I have not found that to be the case - certainly with a 4 inch thick blank. I really should try a smaller blade. I would suggest you do that and let us know your results. I'd be inclined now to go for a 1/4 inch blade.
Especially if the bowl is less than 3 inches thick, I tend to just axe it. I don't have the chainsaw technique that Rob Wood has. I know he roughs his out with chainsaw, and I would like to see just how he does that.
I would have thought the bandsaw's tilting table would be a boon to give a tapered blank, but I have too often found the blade will bind in the kerf. Again, perhaps a smaller blade is indicated.
I have had some success to cut out a cylinder-blank on the saw, and then to cut a taper off that with the saw. But by the time I have done all that, I rather think the axe may be better.
I'd practice with a few thick blanks that you are happy to discard. Find out how thick you can cut, and what radius circle you can cut. And only use a good, sharp blade...

Re: Bandsaw bowl preparation

PostPosted: Fri Mar 20, 2009 8:34 pm
by Nicola Wood
Robin was trained in tree surgery before he started to turn bowls and uses a small tree surgeons chain saw to cut the blanks. This is not a tool for the uninitiated and I suspect the techniques he uses are similarly unsuitable unless you are very skilled with a chainsaw. I know he'd dearly love to get a bandsaw, but I think the electrics in his barn aren't up to it.

Re: Bandsaw bowl preparation

PostPosted: Fri Mar 20, 2009 9:51 pm
by Bob_Fleet
Cutting a circle with the the bandsaw table on tilt isn't too easy.
Basically you are cutting a whole series of circles each with a different radius as you turn the wood.
Good way to twist your blade.

Probably more likely to work if you take a lot of short straight passes to achieve it.

You can do the largest diameter with the bed flat to give you a start.

I find it doesn't like greenwood too much either.

Re: Bandsaw bowl preparation

PostPosted: Fri Mar 20, 2009 10:37 pm
by SeanHellman
You can cut out bowl blanks easily with a bandsaw with a tilting table, but I would recommend a bandsaw costing £1000 plus with a 16 amp supply, anything below this will not really have enough power, especially using greenish wood. Blades will cost at least £16 a go and do not last that long with this sort of work. The thicker the wood the newer the blade needs to be.

Re: Bandsaw bowl preparation

PostPosted: Sat Mar 21, 2009 10:10 am
by Andy Coates
At last! Something I can contribute with a degree of experience...

As a power lathe user, I use a bandsaw for blanks all the time, and I cut hundreds of blanks from wet wood up to 7 3/4" thick.

The best blade for the job is a 3/8 4 skip, and it will manage all sizes of blank with a range from 5" up. The narrow blade allows for cutting the curve, whereas a wider blade has difficulty getting "around the corners".

Most power lathe turners who prep their own blanks cut to a true circle, but this is a pointless excercise on two counts...

1) You have a lathe and gouges to make the blank round
2) Repeated cutting of circles on a bandsaw removes the set on the blade, making the blade useless for anything other than round blanks.

For the polelathe turner, using the tilt on the bench would be a real boon, I can see, and when I have used it it works very well on the straight cut method, less so when you try to cut a circle on the tilt...especially with deeper blanks. You will lose the odd blade doing this.

As Fleet said, the best approach is to scribe the circle and then take straight cuts to the scribe line to give an hexagon first, then take the triangular corners off again, and so on until you have a virtually round blank. A 10" blank, 3" thick, would take me a couple of minutes in this fashion.

Good blades are available from Hamilton Edge Tools, and for my Elektra Beckum are about £7 each when bought in a pack of ten.

Hamilton Edge Tools Ltd
Grange Industrial Estate
Llanfrechfa Way
Cwmbran
Torfaen NP44 8HQ

Tel: 01633 838900

Re: Bandsaw bowl preparation

PostPosted: Sat Mar 21, 2009 11:20 am
by Nicola Wood
ahhhh ... the closet power lathe turners are coming out into the open now :lol: :lol: :lol:

Re: Bandsaw bowl preparation

PostPosted: Sat Mar 21, 2009 1:02 pm
by paul atkin
Andy Coates wrote:At last! Something I can contribute with a degree of experience...





nice input andy :D

Re: Bandsaw bowl preparation

PostPosted: Sun Mar 22, 2009 3:50 am
by jrccaim
Nicola Wood said:

ahhhh ... the closet power lathe turners are coming out into the open now :lol: :lol: :lol:


Well, more power to them, then!

Sorry, I couldn't resist that :oops:

Re: Bandsaw bowl preparation

PostPosted: Tue Mar 24, 2009 5:19 pm
by Morten
Thanks for your input - I've prepared lots of blanks for the (hrmpfpowerhrmpf)-lathe before, but as mentioned; there are power and gouges to get it round... I'll try to tilt the bandsaw table and see how that goes.

And by the way - I just got a chainsaw. And a license-certificate-something-course at work, which means I may use it professionally. Not going to use that one for bowls for the next couple of years though, better get the basics down first.

I need both arms and legs in fully working order :-)

Re: Bandsaw bowl preparation

PostPosted: Mon Jun 22, 2009 5:59 pm
by Bertie
Bandsaw, i allways use a skip tooth 5/8, a 3/4 a bit too wide, plus i found the metal of a 3/4 inch didnt like flexing so much on a small bandsaw - thus not lasting long.
8 inch blanks wet wood, or dry fine, straight round then again with the bed at 30degrees to do the undercut - nicer to burn than shavings.
Sharpening the blade - easy enough to do by yourself. The easiest tool being a dremmel with a good correct sized stone.
Cleaning - many recommend parrafin, or special stuff in a bottle, the question is what causes the blade to clog, if the answer is resin and sap, then how does that substance get transported around the tree.
I usualy stick the blade in a waterbutt and use my finger nails after the stuff has loosened a bit.
If youre looking for a bandsaw, the best for a small workshop i recon is the startrite 352, blades are a good price and startrite were allways the bandsaw people.
I tried to buy a small jobbie at auctions but there was so much competition, prices being quite unrealistic - then one day my dream came true, i found a kitty without a motor(no good if it hasnt a motor is it?), in fact this particular type never came with a motor,(very nice price too) so i built a wooden stand, a wooden pulley and stuck a axminster 1 horse motor underneath - this is actually more powerful than a single phase 352.
A classic way of managing bowl blanks was actually a circular saw, just cut the corners off and keep rotating the thing, but noisy, messy and dangerous.
Cheapskate, use a arbotech, quick, easy cheap and fast.

Re: Bandsaw bowl preparation

PostPosted: Mon Jun 22, 2009 9:48 pm
by Robin Fawcett
Bertie wrote:Startrite were allways the bandsaw people.


That's a name I have always associated with quality bandsaws - are they no more ?

PS I think a chainsaw is a good quick way to prepare a bowl blank. Bit like carving big mushrooms

Re: Bandsaw bowl preparation

PostPosted: Tue Jun 23, 2009 12:26 am
by Bob_Fleet
Record power tools have taken over Startrite.
I recently had to get a spare from them

I'm using Starret blades - made in the Scottish Borders and I get a 10% discount as I have a "TD" postcode.
:) :) :) :)

Re: Bandsaw bowl preparation

PostPosted: Tue Jun 23, 2009 8:06 am
by gavin
Robin Fawcett wrote:PS I think a chainsaw is a good quick way to prepare a bowl blank. Bit like carving big mushrooms

- could you please offer us a tutorial, with pictures?
I have struggled to hold down the log as I am chainsawing it.

Re: Bandsaw bowl preparation

PostPosted: Tue Jun 23, 2009 9:21 am
by Daniel
Hi,
a little, simple idea to hold down the bowl blank and not cut the fingers with the chainsaw.

I think the friction between the vertical round bar and the upper horizontal block (with a hole in the diameter of the round) will hold down the bowl blank.
So you have both hands free for the chainsaw.
Once I have the time I will try this, I first train myself to axe out the blanks.

Daniel

Image