For a lot of small, perhaps fairly dense, growth I prefer a garden saw of the comact sort. I bought a Spear and Jackson Garden Predator a few years ago and it's been very useful. Looks as if it's been rebadged:
There's sometimes quite a lot of relatively small stuff, such that the human battery gets depleted, and recharging it is a bit trickier than plugging into a car charger.
The Ryobi One style of saw looks interesting, thanks. I was also a bit dubious by the batteries on some of the other tools like the Bosch - 10.8V
1.5Ah, which surely can't last for very long.Theo
In message , PeterC writes
+1Those saws were mentioned here a couple of years ago, and I immediately bought one. I use it for smaller stuff including small logs and it so easy, not worth digging out a power tool.
The trick to controlling vibration on a recip saw is to make sure you push the blade guard firmly against the thing being cut. That stops the saw body moving.
You can also get some scissor action battery powered chain saws for pruning that are quite effective.
I have a small recip saw which I mainly use for plumbing and some building work:
Its good at getting into tight corners where a hacksaw is the only option, and its very quick for lopping off things like 40mm wast pipe and even trimming 110mm soil pipe. It also shares batteries with my small drill driver / ID combo.
If I stick a "green wood" blade on that its not bad for a quick bit of pruning - you only get 10 mins or so of work out of a battery, but the batteries are small enough to have a spare in your pocket.
The vibration results from the reciprocating mechanism inside the saw moving back and forth internally not from saw body movement. The more expensive low vibration models have internal dampers to reduce this vibration. Attempting to damp it externally by pressing the blade guard more firmly against the work is merely a more efficient means of transferring those vibrations through the body and up the arms.
michael adams
...
Nice job! Done for no sensible reason other than because you can! ;-)
I think we are talking at cross purposes...
I am describing the problem many seem to have with recip saws where they end up with the blade snagging/sticking in the work and then the machine trying itself to reciprocate. There the more rigid coupling helps prevent it.
What you are describing is the internal vibration from the mechanism itself. (still undesirable, but not in the same league as when the machine decides it wants to move back and fourth rather than the blade!)
I was describing vibration arising in normal use.
And I strongly suspect that any reasonable person on reading your statement
"The trick to controlling vibration on a recip saw"
would be forced to conclude, rightly or wrongly, that you were too.
Vibration is a problem which affects all users of reciprocating saws which apparently can represent an actual health hazard if non-dampened saws are used for prolonged periods.
Such a pity then, that you didn't post "The trick to controlling snagging on a recip saw".
michael adams
...
Not exactly a success. It didn't cut any better than the battery one and it was going the wrong way. Showed some useful 3D printing though.
I have a B&D alligator chain saw bought from a boot sale for ?10 its ideal tool for pruning woody shrubs but never seen one that runs on a battery as yet
-
Its a part of the problem - if you float the blade on the work, then some of the movement to and fro will be in the machine, and not the blade. Place the blade stop hard against the work and you will eliminate that part of it.
Same is true of many power tools - especially anything with a oscillating or reciprocating action including sanders and jigsaws.
I stand by the statement... you get a marked reduction in vibration of the tool body if you brace it correctly.
Perhaps you just need a bit more practice using one, and then you can post some useful advice?
The second attempt[1] was altogether a better solution though.
The first attempt was still a good effort though.
[1] i.e.
Dennis seems to be missing the point completely.
For those who wonder why I make these things, the answer is simple: It's a hobby that I really enjoy, that's all.
I like to see skilled people doing off the wall stuff.
Indeed. Its like there are some youtube videos (by John from the Doubleboost channel IIRC) when they built a jet engine from scratch, and fitted it to a go cart... loads of numpties commenting that it was a waste of time because a motor bike engine would have made it go faster!
The blade and the internal reciprocating mechanism in the machine are rigidly connected via the chuck. While the body of the saw vibrates as a result of being connected to this reciprocating combination of parts.
How could one end of this reciprocating combination of parts move, and not the other ?
I haven't snipped or chosen to ignore the remainder of the points which you make to which I'd be happy to return. However to save any further misunderstandings I think it best to proceed one point at a time.
So how could one end of this reciprocating combination of parts - the blade and the mechanism move, and not the other ?
michael adams
...
It looks like it was quite skilled but also not good design decisions. As a prototype its quite good.
And I don't miss the point, its to make a youtube video so they can get some revenue from adverts.
The same as people collect dashcam clips and make videos to generate cash.
Agreed
It can't - it must obey the laws of conservation of momentum.
if you simplify it to two connected masses - the saw on one end and the blade on the other. The saw is alternately pushing and pulling on the blade - accelerating and decelerating it. It having a low mass will accelerate quickly. There will be a matched reaction in the movement of the saw body, but it will be at a much reduced velocity due to the substantially greater mass of the saw.
As you add load to the blade, you are increasing its effective mass and inertia. So the velocity of the matched reaction of the saw will increase (i.e. increasing the vibration level).
So if you take this to its ultimate conclusion where you add enough load to the blade to in effect fix its position (say lopping a tree branch that closes on the blade), then you have the mass of blade plus a tree on one side, and only that of the saw on the other. The vast bulk of the movement will now be the saw body itself - causing substantial and very uncomfortable levels of vibration.
Take the example above when cutting a branch. Assuming the blade is still free to move, you get most movement in the blade, and some in the saw. If you now push the saw's rest against the branch you are coupling the mass of the saw to that of the branch. So the momentum equation has blade and friction "mass" on one side, and saw body + tree on the other. So you have massively increased the inertia of the saw body, and thus reduced the velocity of vibration.
(Also for half of the cycle (the "pulling stroke") you now have closed system where the pull on the blade is exactly matched by the push against the saw's rest - eliminating acceleration of the saw body in one direction completely).
Indeed, and he also posted the second revision of the design which addressed the issues found in the first.
I would be surprised if that actually was the point. It struck me as a chap who enjoys model engineering and sharing it. Yup it has the trappings of revenue generation now, but he has been posting videos for
8 years or more, and the early ones have no affiliate links etc.Although that requires no real technical ability, and can survive with no real production values. It succeeds because the youtube algorithms promote that kind of click bait stuff these days.
Building a technical content based channel with high production values, good camera work etc takes much dedication and significant effort over and extended period. Its also difficult to do on a regular basis without financial support of some form. Its not uncommon for these guys to spend
20 hours or more on each hour of finished footage. To sustain output at that level basically means it needs to be a full time job.
.....................................................................................................................
Indeed. This is the normal vibration I've been talking about
In other words where the blade snags or sticks in the work, a possibility you suggested earlier. A situation which is fairly easy to replicate simply by taking hold of the saw, clamping the blade in a bench vice, and squeezing the trigger. Whereby it's the body of the body of the saw which oscillates violently back and forth in the hands of the operator against the blade, which is held firmly in the vice. Causing as you say "substantial and very uncomfortable levels of vibration"
But any and all of which would of course be brought to an immediate halt, by the simple expedient of the operator simply releasing the trigger.
So that, if you're seriously suggesting that vibration from this source represents a very real problem as compared with normal vibration, or any sort of problem at all for that matter, then its necessary for you to come up with some sort of satisfactory explantion as to why, following that initial kick, any operator of that saw would be foolhardy enough not to release the trigger. Which most certainly would be the instinctive reaction I'd have thought.
Or leaving instinct aside, why would they ever think of doing this (not releasing the trigger) a second time ?
As with the blade firmly stuck in the work, the whole weight of the violently oscillating saw, as held in hands of the operator, is now supported at the point where the blade enters the work. Greatly increasing the likelihood that it would snap-off at this point; making the subsequent removal of the broken tip from the work all the more difficult.
Why would anyone ever want to do this ? Why wouldn't they simply release the trigger at the first opportunity ?
Indeed. In such circumstances the combined mass of the saw and the branch/tree would easily dwarf the mass of the oscillating blade and would thereby clearly reduce vibration by a substantial degree. Were it possible that is, to clamp or otherwise securely attach the shoe/guard or any part of the saw body to the work. Although not in this case with the aforementioned bench vice, unfortunately
As it is however, in order to keep the vibrating body of the saw in close contact with the work requires considerable effort on the part of the operator. In fact it amounts almost to a form of torture. Slacken your effort in any way and the vibrations will get a lot worse, an awful lot worse, and we don't want that, do we ? So push!
This is the reason why using such saws for any length of time is so very tiring, and why other means short of clamping the saw to the work - using counterdirectional shafts or damping the shaft at either end of its travel - have been sought in order to lesson the normal vibration which is the real bugbear of such saws.
As I originally said; and to which you took such exception for some unaccountable reason, which is yet to be fully explained.
Or if you don't want to take my word for it, it's safe to assume I'd imagine that all the people who've been using such saws on a regular basis for protracted lengths of time since the 1950's can't have all been mugs. Similarly the competing manufacturers of such saws. And that had there been some simple solution to this problem as might be suggested nowadays on websites, but formerly perhaps in articles in DIY magazines and the like, then this would have become standard practice decades ago.
michael adams
...
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.