Bandsawing your blanks, or not

[NeilS]

I though it was about time I measured the difference between the time it takes to prepare a blank on the bandsaw before rough turning it and just rough turning it as it is as a half log billet. The test pieces were two approximately equal sized green half log billets that would yield 8.5" pre-turned bowl blanks.



461916


As most of my bowls are pre-turned from freshly cut green wood that was the focus of this exercise.

The first piece was just put on the lathe and rough turned as a half log billet.



461917


The time to do that was three and a half minutes.


461918


The other piece was trimmed first on eight sides with the bandsaw.



461920


Then rough turned.


461921


The combined time to trim on the bandsaw
then rough turn was close to 6mins.


461923


I included the time to set the jig on the bandsaw to the required diameter. When working in batch mode I might put a half dozen blanks of the same diameter through the bandsaw before needing to change that setting, so that might bring the average time down on the bandsaw, but not by much.

The test pieces were reasonably symmetrical so the initial speed on the lathe for the blank that had not been prepared on the bandsawed was not as slow as with an unbalanced blank. Unbalanced blanks have to be run very slowly to begin with and for them there might be an advantage time-wise in trimming them on the bandsaw first.


461915

461914


There are also times after the log is split that the selected part of the half billet to be tuned will be quite offset and very unbalanced if turned as it is. I cut full logs to 1.5 times the length of the width of the log to allow for the best blank position, which can't be known until the log is split open.


461922

However, I find that for most pieces it will be quicker to just rough turn them as half log billets. This timed experiment confirmed that.

Adding an extra manoeuvre (moving the pieces from the bandsaw to the lathe) accounts for some of the additional time over starting on the lathe and doesn't add anything of intrinsic value, unless you are in training to become a removalist.

Some other considerations.




Near to round blanks are a good and safe starting place for new turners. That is where good turning techniques should be practiced and perfected. Half billets require an interrupted cut that can wait until fully confident with contact cuts.



I didn't add in the time to clean up the additional and widespread shavings produced from the extra turning required with a billet. It is much quicker to push the off-cuts from the bandsaw table into a bin than retrieve the far flung shavings from the lathe. Then there is the extra bags of shavings to dispose of. Any early turning excitement about producing piles of shavings fades after about the first hundred bags of shavings!



461913




Care needs to be taken with the 'wings' of the billet as you get near to the faceplate side, both from a safety perspective if they come away in a large chunk but also the tendency for them to split back along the faceplate side. I use a scraping cut with the bowl gouge to true up and chamfer the edge of the faceplate side to avoid that tendency to split off.



Sturdy tools work best with the interrupted cuts required for rough turning a billet. I wouldn't for example attempt it with an half inch gouge. As you can see from the above photos I use a very sturdy cast iron toolrest and my largest gouges. At least 5/8", preferably 3/4", and, because I have it, my 1" gets used the most, but that is a luxury and not essential; it probably only saves me 30secs per blank and they are hard to come by and fairly exxy. If you don't already have something larger than an half inch gouge, the cost of tooling up with some larger gouges might not be justified alone for the time saving.



Last point to make is that fully seasoned hardwood blanks are a different equation. They are slower to turn (you also spend more time resharpening when turning them) and the bandsawing is almost as quick as with green wood. I haven't timed the difference, but expect that pre-bandsawing would come into its own there. So, a good big bandsaw is still required.


Is anyone else turning log billets in this way?

[Optimark]

I too worked out that it is easier and quicker to go pretty much straight to the lathe and miss the band saw; mostly. :D

About 2 years ago I did a similar time test and decided that, apart from the extra shavings needing to be picked up and disposed of, missing the band saw was a brilliant time saver. I mainly use a 19mm P&N deep fluted bowl gauge which is brilliant at removing stuff quickly. I also find removing bark prior with an air tool powered chisel, makes the rough turning far safer and aids in reducing time getting through the bark. I pretty much do exactly as you do.

Attached is a series of pictures all taken on the same day. The first is loading the blank, which is approximately 800mm, in length and very heavy as it was waterlogged; I had a mate help me get it up and onto the lathe. The second picture is just prior to lunch, the white stuff is end seal to reduce and/or eliminate cracking. The third picture is after lunch and when the blank became rounded.

I didn't put this through the band saw as it wouldn't fit, but I did cut two of the corners with the chain saw to ensure it would fit onto the lathe. The diagonal was a bit over 900mm (my lathe can do about 975mm from memory). I had intended to round it with the chainsaw, but the time taken to slightly round one corner convinced me I was going to waste time and effort; so I put it onto the lathe and started turning. This blank did take a bit longer than normal to get speed up, but I certainly know this was a quicker method over rounding it. Once speed was up, the removal of unwanted material kept on accelerating and I was there before I knew it.

This blank was about 3 hours old, so it doesn't get any greener than that. Once the corners were rounded and I got a bit of speed up, water was literally spinning off in a circular spray.

Mick.



461926461927461928

[NeilS]

I also find removing bark prior with an air tool powered chisel, makes the rough turning far safer and aids in reducing time getting through the bark.


461926461927461928


Thanks for the contribution, Mick.

A good rundown there.

Yes, as you say, the bark slows down the roughing cuts. I find the wet bark clogs the gouges so they don't cut so cleanly. I use a bolster and hammer to remove the bark if it will come away readily (the bark on some species is more tenacious than others), otherwise I just proceed with pull cuts and the bigger gouges to begin turning it off with peeling cuts. I don't have a compressor and have thought about one of those mini rotary hammer drills that will take a small spade bit for quickly removing the bark, but haven't as yet got around to doing anything about that.

How are you finding the Revo 36/24?

[Dalboy]

For me time is not an issue as I am a hobby turner. Yes I am confident in turning from square stock for want of a better word, all the same I tend to use a compass to mark circles on the logs once they have been slabbed this allows for best cutting and also gives me maybe one or two extra blanks as most of the trunks I aquire are quite big in the diameter.
I don't use a jig but just follow the circles I have drawn, for those that are just large enough for one blank I still use the compass and cut around the marked circle the corners I find Ican use to make knick knacks like little minature bird houses and also with a nice grain use them for pen blanks.

[Optimark]

Neil, I would suggest the biggest changes for speed I have done, regarding rough green blanks into a round bowl shape, have been, in no particular order.

A chainsaw, picked up an Aldi electric chainsaw and haven't looked back, beats an axe and/or wedging.

A bandsaw, certainly beats axing and/or wedging the tubes of trunk into halves.

Variable speed lathe for heavier blanks, not so much an issue with out of balance lighter blanks, but anything over about 25Kg was iffy for me, as my starting speed was 178rpm and you go up in chunks which is what my previous lathe did.

Air chisel for removing bark, surprisingly quick and unbelievably easier to de-bark with something like that. The air chisel came about because my 25 year old little air compressor died. I upgraded to a low end, 50 litre tank, air compressor. My previous compressor was a 15 litre tank unit and meant that whenever you used some air, the compressor kicked in.

If I was to suggest the cheapest way to get an air chisel for de-barking, the Ozito from Bunnings as well as a litre of their air tool oil, which you will need before you first fire up an air tool. The one litre bottle will see me out; you use so little.

Ozito 10.2mm Shank Air Chisel | Bunnings Warehouse (https://www.bunnings.com.au/ozito-10-2mm-shank-air-chisel_p6290423)

Ozito 1L Air Tool Oil | Bunnings Warehouse (https://www.bunnings.com.au/ozito-1l-air-tool-oil_p6290462?gclid=Cj0KCQjww7HsBRDkARIsAARsIT58SHwCrR2KkpihnVGKLkD2tR3y2RTJ5KVcaqOSW0-_gpKnMXVde1kaAp3iEALw_wcB&gclsrc=aw.ds)


My air usage is modest, but with the knowledge that I was certainly going to be using air for chiselling and maybe something I don't know about in the near future, a larger tank unit made sense to me. My air chisel is from one of Aldi's specials; $15 or thereabout. However the air chisel will consume around 70-80 litres to 150 litres per minute, but with a bigger 50 litre tank and 8 Bar pressure, I can de-bark about 4 halves before the tank pressure drops enough to kick the compressor into action. With me moving blanks around and whatnot, I have nowhere near taxed the air compressor as a unit.

Having an air compressor is also a boon for ensuring there is no dust on the drive spindle or chuck threads, or in Morse tapers; among other things.

Below, is how I used to do it in 2016. It wasn't too long after these pictures were taken, that I thought I'm doing too much hard work. So I embarked on a long term strategy of adding and/or upgrading. Read the file names for descriptions.

Bandsaw, chainsaw and variable speed heavier lathe; completed the strategy last year.

Working on an overhead hoist to get blanks onto the lathe. :rolleyes:

As for the Revo Laguna 24-36, extremely happy with it. I will have had it for 12 months shortly, I'll be doing some sharing of my experience with it in the not too distant future.

Mick.



461934461935461936461937461938461939

[Old Croc]

Neil, sounds good considering you are turning green, I would think that the results would be completely different for dry wood.
Rgds,
Crocy.

[Colin62]

As for the Revo Laguna 24-36, extremely happy with it. I will have had it for 12 months shortly, I'll be doing some sharing of my experience with it in the not too distant future.
I’m keen to see that - it’s the lathe I aspire to buying.

On the topic at hand, I tend to knock the pointy bits off with the chainsaw, and as long as I can get it balanced enough to spin on my lathe, I turn the blank round from there. But that’s just as a hobby turner who isn’t all that productive at the best of times.

[NeilS]

Neil, sounds good considering you are turning green, I would think that the results would be completely different for dry wood.
Rgds,
Crocy.

Agreed!

[NeilS]

I tend to use a compass to mark circles on the logs once they have been slabbed this allows for best cutting and also gives me maybe one or two extra blanks as most of the trunks I acquire are quite big in the diameter.

I don't use a jig but just follow the circles I have drawn, for those that are just large enough for one blank I still use the compass and cut around the marked circle

Likewise, Dalboy, I always use a compass or trammel bar (for extra large blanks) to mark out the placement of the blank circles to maximise the best use of each piece of wood. You might not be able to see it but the pieces shown in my first post are all marked out with their selected circle areas, just a scratch to get a diameter measurement to calculate foot tenon size and also a centre point that is then drilled to take a pin for either the bandsaw jig or locating the faceplate in the preferred position if going straight to turning.

I give a lot of time to blank placement; sometimes a lot more time than actual turning. It is one of the most important steps of the whole process for me.

Freehand cutting to a marked circle is OK if starting with slabbed pieces, but not an option for a half round billet where the flat face will be down on the bandsaw table, thus the jig that locates the cut at the selected position and diameter.

If I'm bandsawing a seasoned blank I use a 1-1/4" 3TPI blade, so eight quick straight cuts using the jig and it's sufficiently round to go on the lathe.

Dalboy, if you are a hobby turner, which most of us are, just keep doing whatever you enjoy doing. After all, that's the purpose of a hobby! For some turners sharpening is a chore, but I could do it all day and never get bored.

[NeilS]

Neil, I would suggest the biggest changes for speed I have done, regarding rough green blanks into a round bowl shape, have been, in no particular order.

A chainsaw, picked up an Aldi electric chainsaw and haven't looked back, beats an axe and/or wedging.

A bandsaw, certainly beats axing and/or wedging the tubes of trunk into halves.

Variable speed lathe for heavier blanks

....

As for the Revo Laguna 24-36... I'll be doing some sharing of my experience with it in the not too distant future.



At last count I have 5 chainsaws, so agree with you on their value in processing tree trunks into usable blanks.

A bandsaw is invaluable for doing many things, but I decided a few years ago to get a 28" ripping blade (and square chisel chain) for my largest Husky chainsaw to split logs into half billets immediately the log was cut into lengths. I found that reduced the checking that radiates from the centre heartwood that seems to start immediately the log ends are exposed. That way the billets are ready to go straight onto the lathe.


461955

And, yes, variable speed is essential if there is any imbalance in blanks to begin with; dialling back to eliminate vibration (or occasionally up to get past a resonant frequency) and then being able to nudge up the speed progressively as the piece comes into balance.

[NeilS]

I’m keen to see that

Me too, I look forward to reading you Revo 24/36 review Mick.

[Optimark]

Me too, I look forward to reading you Revo 24/36 review Mick.

Hmmm, better get my A into gear then. I didn't think there would be that much interest as it isn't a mainstream lathe in this country.

Mick.

[tonzeyd]

6 minutes to turn a rough bowl... i've got some serious speeding up to do!

It takes me 10 minutes just to mount a bowl!

[Old Croc]

Hmmm, better get my A into gear then. I didn't think there would be that much interest as it isn't a mainstream lathe in this country.

Mick.
Mick is yours the cast iron model or the steel welded bed? If it's the cast iron one, I will be interested in your review also.
Rgds,
Crocy.

[Colin62]

Mick is yours the cast iron model or the steel welded bed? If it's the cast iron one, I will be interested in your review also.
Rgds,
Crocy.
As far as I can work out, if it’s a Revo, then it’s got the steel bed. The cast iron bed was the previous model, and was just called the 24-36, with no “Revo”.

edit: Of course after saying that, within five minutes I found a reference to the older ones also being called Revo.

[Nubsnstubs]

I went to the Laguna site, and in the features/specs page, this is in there. Steel Bed: ASTM A36


Mick, have you ever thought of something other than an overhead lifting system?? I thought about that at first, but was always had concern about the the weights I might be subjecting the joists to. I then decided to use the lathe to bear the weight rather than my shop roof/ceiling. I used a trailer jack, a friends welding/machine shop, and a little bit of ingenuity. I made a video of it in use, but did a really bad job of showing how I use it. If you have about 30 minutes free time, watch the whole video. The first 14 minutes has a little better detail of the jack. YouTube (https://www.youtube.com/watch?v=lK3ZXacwgH4&t=1107s)

I don't normally do edited videos, but this one has been only after I turn on the lathe. I mounted 2 pieces and both are in real time.

Croc, when you were here, didn't I show you the jack?? ............. Jerry (in Tucson)

[Old Croc]

As far as I can work out, if it’s a Revo, then it’s got the steel bed. The cast iron bed was the previous model, and was just called the 24-36, with no “Revo”.

edit: Of course after saying that, within five minutes I found a reference to the older ones also being called Revo.


I went to the Laguna site, and in the features/specs page, this is in there. Steel Bed: ASTM A36

Croc, when you were here, didn't I show you the jack?? ............. Jerry (in Tucson)
Guys, mine is marked Revo 24/36 and it's the original cast iron model, same castings as a Powermatic, then they changed to a welded bed just like a Robust.
Jerry you did show it to me and I described how i have a swing arm above my big bandsaw and my metal lathe to change chucks. You were considering my application.
Rgds,
Crocy.

[NeilS]

6 minutes to turn a rough bowl... i've got some serious speeding up to do!



Well, that was just the outside, including the time to pre-trim on the bandsaw. But, three and half minutes for the outside if the billet is mounted straight onto the lathe.

If the billet is a bit unbalanced then the speed has to be slower to begin with and the time to completion will take longer, but less than if I also pre-trim on the bandsaw.

Very unbalanced pieces (unless I'm after that as part of the design) have to include the time to pre-trim on the bandsaw or chainsaw.

I tend to rough turn a batch of outsides first, then go back and rough out their insides in batch mode. It takes me longer to turn the insides as that includes making a measured internal recess for remounting later. So, for a blank that took 3-1/2mins to rough turn on the outside it would probably take me about 6mins to rough turn the inside. Say 10mins all up for just the rough turning, then add the time to mount & dismount for the outside and again for the inside, that would take it up to 15mins per bowl. For diameters up to 12" I average about three per hour, so far from any record there. I can do more if just turning for an hour, but for hour after hour and including tool resharpening and occasionally wetting the whistle three an hour is about it. Larger or more complicated pieces take longer.

Managing the process from green to seasoned without too high a blank loss also takes time and re-turning and finishing the pieces later takes even more time yet again, especially the sanding/polishing.

Add to that workshop maintenance and preparation, documentation and gallery prep and distribution, then the time averaged out per piece is better measured in hours, not minutes.

Speed isn't a goal in itself for me. As a kid I worked a night shift on a production line and soon realised how soul destroying that was for the adults who had no other options. You can buy a wooden bowl that come out of sweat shops in developing countries that are sold in your local supermarket for 1/10th of what ours will sell for in a local gallery. We are making something more than a mass produced item.

I eliminate any unnecessary steps in the making process not so much to make it quicker but to allow me to concentrate on the aesthetics of what I make. That is what I enjoy doing and I guess why my buyers are willing to pay ten times more for a bowl from me than from the supermarket shelf.

Speed in itself is overrated, IMO. The fastest turners in the world got that way from doing a lot of it over many years. What do they say, it takes 1,000 hours to achieve mastery. Behind that is a less obvious fact; they all had to be selling a huge volume of work to get to that level of mastery. Turners like Raffan, Lucas, Escoulen, Batty and Mahoney all produced items that sold well due to their aesthetic appeal that then allowed them to do yet more turning enabling them to further developed their mastery.

Tonzeyd, concentrate on mastery and your turning speed may follow, as a byproduct.

And, don't forget to enjoy yourself!

[Optimark]

Mick is yours the cast iron model or the steel welded bed? If it's the cast iron one, I will be interested in your review also.
Rgds,
Crocy.

Crocy, it is the later steel bed unit.

Enough of this subject, otherwise we'll completely derail this very interesting thread. I'll start doing my impressions of the 24-36 and have something for the forum shortly.

Mick.

[NeilS]

It takes me 10 minutes just to mount a bowl!

I'm sure you are exaggerating there, Tonzeyd, but one thing I have done to speed up the chucking process is to mount the chuck hex key in a reversible drill with adjustable tension. Set the tension to sufficiently hold tenons or recesses but not over tighten the jaws. It's both quicker and easier.

462033

[NeilS]

It takes me longer to turn the insides as that includes making a measured internal recess for remounting later. So, for a blank that took 3-1/2mins to rough turn on the outside it would probably take me about 6mins to rough turn the inside.

I rough turned the insides of that batch of bowls yesterday with the stop watch running. The 8.5" blanks that took an average 3-1/2mins to rough turn on the outside took an average 4-1/2mins to rough turn out the insides. So, quicker than I expected, but again no speed record there.


462034

The measured internal recess for re-chucking later consumes some of that time and I also like to thin down the thickness towards the base (that area needs less thickness as there is less warping there compared to the rim) and that involves me stopping the lathe to check the thickness with the calipers.

Thinning towards the base close to final thickness allows for movement to accommodating warping which I find reduces the loss from splitting.

But, I'm also wandering off topic now, which was on about the time for blank preparation (or not) before (rough) turning the outsides, and not about the subsequent stages.