Thanks for your explanations Hamish. I think we agree more than disagree; we are just finding solutions in different ways. For example, if I had excessive tear out on a chopping board, I¡¯d just move on to my wide belt sander. Or if I was feeling particularly atavistic, I¡¯d pull out my Sauer and Steiner smoother and get to work.?
I¡¯m also in Australia (Brisbane) and know exactly what you mean about non-Australian timbers machining like butter. Where are you located? Cheers, Lucky
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On 13 Jan 2021, at 9:48 am, Hamish Casimir <hamishcasimir@...> wrote:
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Lucky, In the context of having to change or rotate every single individual blade on a helical cutterhead, I would agree with you.
In practical use, as a serious hobbyist, or small fine woodworking business, the solid carbide cutters stay sharp many times longer than the standard blades. This means you don't need to change anywhere near as often. If you're a small volume, high quality
worker, it could be many years before you need to.
?It also means if you get a nick in a helical carbide blade you can rotate the offending 1-2 blades. With regular knives if you get a nick, you have to change out the whole set.
I would also agree that straight grained purpleheart planes very well with regular knives. The fiddleback stuff gives me nightmares just thinking about it. Helical cutters no prob.
Where the helical cutterhead really shines is things like laminated cutting boards. I usually do several small batches a year. Sometimes, I make the mistake of orienting a laminate, the with the grain of one running in the opposite direction to all the
others. You get a nasty surprise when try to flatten it after glue up, with the tear out on that one area, using regular blades. With a helical cutterhead, there is no problem. Straight to finish sanding, no time consuming divetts to sand out.
The machine I have is about 11 years old. I believe Tersa blades might have been an option at the time(???). I had the regular reversible blades, until I changed out the cutterhead last year for a helical. The reversible blades would be slower than Tersa,
to change, but I didn't mind so much because I was used to the old style jointers, ancient method of using wrenches, where you tighten one bolt and the knives would move out of alignment somewhere else, and it takes hours to get a decent change.
I'm down here in Australia, where most of our hardwoods make working with oak feel like a softwood, and also have an abrasive high silica content to boot. I really notice the difference, when working with fine Northern hemisphere woods like walnut, cherry,?
maple, or oak. They feel like planing butter in comparison.?
Hamish.
Very pertinent points Hamish.
But what about David¡¯s rejoinder about the speed issue of changing out blades? Your reference to ¡°a lot less time consuming¡± in change over is simply untrue. Maybe you¡¯re thinking about older machines which do not have indexed straight knives?
Even then, I¡¯m not sure you¡¯d be correct. Tell us more!
Many share your opinions, but this matter (straight versus helical) is absolutely not a ¡°no brainer¡±. I¡¯m a fine furniture maker, professional, and I use many exotic timbers, including Purple Heart (although not very often; you lucky bugger!!
:-). A new set of Tersa blades (which take two minutes to install) cuts Purple Heart very well indeed. You might agree, that the cutter head diameter (5¡± or larger; versus 4¡± or smaller) plays a very large part in whether there is tear-out. Thoughts?
So, to be clear, I¡¯m comparing your comments with my experience with half a dozen thicknessers, including my current machine which is a Dual 51, 5¡± cutter head with Tersa knife system. I love the Tersa system.
Lucky
Dave you are correct regarding the type of material you mainly use having an effect on finish quality. Say if you had exclusive access to clear, straight grained softwood, or mahogany,
you get a quality better finish from straight knives.
If you are a fine woodworker then even if you are using top quality softwood, you are still going to have to handplane or finish sand for the best surface.?
If you are doing entry level, high volume production work in softwood, and can get good quality wood, I'd go for conventional blades.
If you work with many different woods, hardwoods, highly figured woods, less than perfect grain or knots, regular blades can give you serious tear out. After planing some fiddleback
purple heart, for a small tabletop, with regular knives, I needed to spend the best part of a full week scraping, then sanding the top smooth enough to get a top quality finish.
Not something you want to do when time =money.
Horses for courses, when we're talking about specificity. For many and varied tasks I'd choose a helical cutterhead, for its versatility?
?Hamish.
Hamish - I agree will everything except helical head.?
Too many people say that like it¡¯s a no brainer. ?It¡¯s not. Depending on what your main material is , it might leave a worse finish.?
As fir quickness of setting / changing blades , a Tersa head or similar is 10 to 50 times faster for changeover and doesn¡¯t require a torque wrench.?
Dave
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How serious of a hobbyist are you? Wanting to invest in a Hammer machine makes me think you are either a very serious hobbyist, small scale professional,? or someone with plenty
of money looking for something to spend it on.
If you are serious, yes definitely Hammer, great machine. I would also suggest?that you buy a model with a helical cutterhead. Less fiddly and less time consuming, changing blades
when compared with straight, one piece knives.? Longer blade life with solid carbide.
The newer cutterhead allows you to plane knotty, or seriously figured timber, or long boards that change grain direction several times, without any tear out. This means significantly
less time, effort needed for finishing. I mean light years difference. I cannot emphasise this enough.
If you have the funds I would invest in the 16" model. I have the 12" model. Yes it is rare that I need to plane or thickness a board wider than 12". I do sell my work occasionally,(not
enough to be a full time maker), and there are times when I really need that extra capacity. Having to do a work around, manually increases the labour time unnecessarily, and increases the cost of the job, cuts into your margins.
Hamish
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David Luckensmeyer