Thread: Bandsawing a Spotted Gum

Originally Posted by Bushmiller

Brett

My apologies as I have just been re-reading the thread as I realised that I may have missed some comments. My apologies also to others who I may not have replied to directly.

You are right the kerf is so thin (1.2mm from memory) that the timber pinching the blade is never an issue. The only time it becomes an issue is when you miscalculate how sharp the blade is and are forced to back the blade out of the cut from part way down the log. Then of course you have to place wedges in the kerf to prevent the balde being knoacked off the wheels.

In fact Spotted Gum so often has growth spring in it that the board behind the cut will actually rise up. I had one extreme example soon after I first started milling where reaching the end of a cut of a log about four meters in length I glanced back at the board to see it had risen abou 200mm in the air. Not a good piece of timber at all. The rotating of the log will tend to minimise that effect, but not completely eliminate it. It is the advantage of having a bed to give reference, but as others have noted it is an additional operation in the milling process that is very labour intensive for a portable milling operation.

The larger the diameter of the log the less chance there is of growth stress being present. I recall somebody telling me he had cut some ancient bridge timbers and as he cut them they" sprung." If growth stress is there is remains there until cut.

With regards to back sawing and quartersawing with a bandsaw you are correct if you are talking fully quartersawn or fully backsawn. However grain at 45 deg qualifies for quartersawn too. A swing saw blade is particularly good for quartersawing as it can take both types of cut in the same.

Regards
Paul

The spring in small logs can be intense...that can be corrected to a point by keeping log increments short,or splitting log in half,also choice of species helps! Steer clear of logs with large sap margins too,they will often contain alot of spring

Originally Posted by pmcgee

Aaaah. Thanks. I don't see signatures.

Turn them on at your Control Panel.

Originally Posted by FenceFurniture

Turn them on at your Control Panel.

No thanks. Takes up screen real-estate.

Originally Posted by MAPLEMAN

T Steer clear of logs with large sap margins too,they will often contain alot of spring

MM

Exactly the case with Spotted Gum. Sapwood up to 40mm thick .

Regards
Paul

Thanks Bushmiller

An interesting thread, I'm considering a portable mill and have spent much time reading about them, I'm interested to see someone "down under" using a bandsaw mill as they do not get good press here in NZ.

Seems our local manufacturers all create blade mills, but for someone who is looking to mill for personal or limited supply their cost is excessive, where as the Canadian / American bandsaw mills are more affordable.

I'm reading into your thread that you where perhaps much more involved in portable milling previously, and that now it is primarily milling timber for your own use?

Could you possibly list your own comments both for & against both bandsaw and blade mills, most of the NZ manufacturers comment on the need to continually sharpen the bandsaw blades but as I read this post you only used and sharpened 2 bandsaw blades in this milling?

thanks phill

Phil

Welcome to the Forums and particularly the Small Timber Milling section. It is a very good place to start, but the timber millers are a little biased in this regard .

You've asked a huge question so I'll get the easy bits over first.

Yes, I used to be more involved with timber milling and I ran both a bandsaw and a swingsaw. I sold the swingsaw when I ceased milling for a living and now just use the bandsaw for my own amusement and needs. Rather than repeat myself this thread explains some more:

https://www.woodworkforums.com/f132/l...85/index2.html

In many ways the bandsaw is more versatile than the swingsaw, although this would be hotly contested by the swingsaw brigade. However, what is undeniable, to my mind, is that a bandsaw is far more difficult to use and this would be why in NZ you have encountered a prejudice against the bandsaw.

I will try to put up a list of pros and cons for the two types on the proviso that others can add their comments or challenge mine, but I will have to give it some thought: Perhaps tomorrow.

Just some comments on the sharpening: Really I used four blades in that I started with two new blades and sharpened them once, but they are both due to be sharpened again before I resume cutting. So longevity of the blade was not quite as good as it first seemed. In times gone by I used to buy and use the blades in sets of five.

The profiler to sharpen the blade is expensive. More than two thousand dollars unless you can pick up a second hand machine.

You might get five to ten sharpenings from a blade and then it will be better to buy new, because it either needs resetting, the bimetal (if you are using that type) has all been used up or the tension has gone from the blade.

The way to check for tension by the way, is to lay out the blade on it's side and place a straight edge along the back edge of the blade. It should touch only in the middle indicating it is still in good nick. If it touches at either end and there is a gap in the middle it means the tension has gone, the front edge of the blade is now longer than the back edge and there will nothing you can do to prevent the blade wandering in the cut.

Are you starting to get a feel for the complexities of the bandsaw?.

Actually I hope Nifty will contribute to this as he has far more experience than me in bandsawing, but I will return with some answers to your question.

Regards
Paul

Thanks Paul

The linked thread makes interesting reading, I've been communicating with Norwood Sawmills and looking at their Lumbermate as we are looking at milling windfall popular primarily for own use, also other NZ timbers most of which you guys would not classify as hardwood.

I'm getting a feel for the bandsaw system from reading primarily American & Canadian blogs, have observed a blade mill in operation and I certainly can see the benefits, but can't justify the cost for own use.

Originally Posted by phill-nz

Thanks Paul

The linked thread makes interesting reading, I've been communicating with Norwood Sawmills and looking at their Lumbermate as we are looking at milling windfall popular primarily for own use, also other NZ timbers most of which you guys would not classify as hardwood.

I'm getting a feel for the bandsaw system from reading primarily American & Canadian blogs, have observed a blade mill in operation and I certainly can see the benefits, but can't justify the cost for own use.

Phil

Rather than hijack my own thread, which I am not above doing, I thought the comparison of bandsaws and circular saws probably warranted it's own thread and would encourage more people to add their twopennyworth so this is what I have started:

https://www.woodworkforums.com/f132/b...2/#post1664640

I hope it answers at least some of your questions, if not immediately, by the time the thread has run it's course

Regards
Paul

Over the last two to three weeks I milled the remaining lengths of the original Spotted Gum. Unfortunately this has yielded a wide range of lengths, thicknesses and widths. The stack which was quite uniform now looks plain blo*dy ugly and even worse it makes a nightmare of the drying processes.

I put another two pairs of masonry nails in a 50mm board and a 25mm board. They had moisture contents of 70% and 55% respectively. The sample boards on the side of the stack read 55% for the 50mm SG and 19% for the FRG. The corrected FRG % is 20%
spotty 4 012.jpgspotty 4 009.jpgspotty 4 011.jpg

I still have to paint the ends on many of the new boards and at some stage in the future I will be looking to start the srude solar drying. The stack is now awkward to operate and this fortunately will be the limit of the height. The concrete blocks are starting to be an issue with a psych session in the corner of the workshop prior to lifting them above head height .

I had to plane up one particularly ugly piece of timber and this is the look of the grain:

spotty 4 002.jpgspotty 4 004.jpg

I've added this pic as I thought it looked cool .

spotty 4 001.jpg

Regards
Paul

Nice looking grain and colour Paul. As you know, I'm a big fan of this very useful timber, and it can often have very nice "average" quality grain, if you know what I mean. Is there the teeniest bit of fiddle going on there?

Originally Posted by FenceFurniture

Nice looking grain and colour Paul. As you know, I'm a big fan of this very useful timber, and it can often have very nice "average" quality grain, if you know what I mean. Is there the teeniest bit of fiddle going on there?

Brett

I thought. "What's he talking about?" However on reviewing the pics you are right, but only the barest minimum . The grain is difficult to see until it seasons a little and darkens. In the past the Spotty to which I have had access has had good interesting grain, but only time will tell. I am optimistic .

Regards
Paul

Yeah, just a little bit to give the bench a nice little bit of zip. Nowhere MM standard of course (have you seen the Jacaranda? bloody ridiculous cruelty, putting stuff like that in front poor suckers like us when it's still green).

Originally Posted by Bushmiller

The stack which was quite uniform now looks plain blo*dy ugly and even worse it makes a nightmare of the drying processes.

Now, now, Paul; it's not about the stack it's all about what comes out the other end. I've stacked uglier and still got great boards. I treat it like a building Each layer level (flat). I noticed, though that you have some boards dangling out over shorter boards, Will you put some blocks in there to pick them up?
Tim

Originally Posted by Tim Creeper

Now, now, Paul; it's not about the stack it's all about what comes out the other end. I've stacked uglier and still got great boards. I treat it like a building Each layer level (flat). I noticed, though that you have some boards dangling out over shorter boards, Will you put some blocks in there to pick them up?
Tim

.

Tim

In a former life I was involved with motorcycles and I met one of the Isle of Man "specialists." I was intrigued to hear him say that he did not attempt to ride "fast" at the Isle of Man: His aim was to ride "well." His point was that if he rode well on such a difficult course, he pretty much automatically rode fast. So it is with my stack. If it is built well I am reasonably sure it will dry well, but the multitude of different thicknesses, lengths and widths precludes that automatic assumption.

In many of the sizes I have cut well oversize to allow for extensive dressing. The 25mm boards, in particular, are intended for kitchen cabinet doors and don't have to be very long so that gives me quite a bit of leeway when I come to recover my required material. I can cut around defects whether natural or drying induced.

The boards that are over-hanging I did start to dock, but then I thought I would leave them long as they were the top row only. If they degrade I have lost nothing and if one or two survive intact it will be a very small bonus. However it does contribute to the stack "ugliness" and does fly in the face of my comments earlier in the thread about keeping everything uniform.

One day no doubt I will cut a stack of 150mm x 25mm boards all 4.2m long and it will be the prettiest drying stack you ever did see, but not this time .

I painted all the ends a few moments ago and with the warmer weather we have enjoyed I expect to see some changes in moisture content over the next month. I am also going down to NSW again this weekend and will be bringing back some material for the solar kiln.

Regards
Paul