On Thu, 20 Feb 2014 15:36:59 -0800, "Lew Hodgett"
Yup, I could buy a cheap knockoff from Harbour Freight for a lot less money. Then I could add on mailing costs, duty garbage and several weeks time waiting for it to come across the border into Canada.
Good idea Lew. I'll keep that idea in mind the next time I want to buy some cheap tool garbage.
On Thu, 20 Feb 2014 19:14:47 -0500, "Mike Marlow"
Well, we've got a Princess Auto which isn't too far removed. But, to tell the truth, the main reason I buy from Lee Valley aside from the quality of their tools is their service. I can search out cheap or quality tools almost anywhere. I *can't* get top notch service if I have a problem or complaint most places.
I'm just about to hit sixty and my wants have changed significantly. Take food as an example. When I was younger I mostly had quantity on my mind. That's changed and now I almost exclusively seek out quality. ~ That concept has transferred over to a significant portion of my life.
------------------------------------------------------------------- It's NOT buying cheap garbage, it is the prudent utilization of ones available resources.
It's all a matter of perspective.
Lew
------------------------------------------------------ Rookie!!
Can certainly relate to your change in perspective of life.
Lew
On Thu, 20 Feb 2014 16:23:14 -0800, "Lew Hodgett"
Ok, I'll let you get away with that one. But, consider a significant amount of the comments posted here in regards to the cheap crap that floods into our North American market.
The demand for all the cheap shit has destroyed much of the quality goods markets that made us great in the first place. All that's left is for us to spiral down the drain. It's a slippery slope that there's not turning back from, at least not as far as I can see.
On Thu, 20 Feb 2014 19:39:06 -0500, "Mike Marlow"
Sure, I know what you're saying. Taking the dead blow hammer that was under discussion, any cheap dead blow would likely do, I can't deny that. For me, it mostly comes down to what's easier or less time consuming. Cost often comes in third.
When it comes to tools, I like most of what Lee Valley sells. If I ever have any problem at all, they take care of it right away. One of their biggest stores is close to where I live. If I can't get there, my closest friend lives very close to one of their stores.
I've got a driver's license, but don't own a car. Because of the chair, for me to go running around or spreading my dollars a little more judiciously, it takes me considerable time than most. I guess my position is a little more unique that most, but it's what works for me. I'll even admit that I'm probably mired in my ways and not so inclined to change.
Oh man Mike, that is almost like saying that it sucks that they don't have Obamacare up there. :-)
On 2/20/2014 5:19 PM, snipped-for-privacy@garagewoodworks.com wrote: ...
Superficially and without proper conclusions, unfortunately.
A demonstration that isn't _exactly_ the same problem, but very closely related is at...
Didn't intend that to sound as snippy as it does, sorry...but, the problem has much to do with the differences between elastic and inelastic collisions which is why I pointed out at the beginning of the subthread you really don't want to get too deeply into the actual physics because it isn't a trivial problem that can be correctly modeled with only a couple of masses with linear springs. Hence trying to draw conclusions on comparison to that as a model isn't fruitful.
While the example video shows an interaction between to solid objects w/o the inner mass of the deadblow hammer, the difference between the two shows the fundamental difference in momentum transfer between (nearly) elastic and inelastic collisions. Therein is the key to the difference in behaviors in the other as well altho it's yet more complex to actually model given the second mass. But, for a first approximation, think of the inelastic case in the video as if that were the impacting interior mass of the deadblow hammer assuming you could deliver the blow w/o the container and you've got the start of a visualization.
Right. Energy that isn't absorbed is useless, however that which isn't moving the struck object is just being absorbed uselessly as heat anyway. I don't see that the lack of "bounce" necessarily makes the hammer more "efficient". It just means it's absorbing energy, rather than the user's arm.
Newton's third law kinda makes this a given.
It doesn't.
No. Correct conclusions and efficiently in depth.
It also depends on your definition of what an "efficient" hammer blow is and what its purpose is. If I remember my physics right, there actually is a _greater_ transfer of kinetic energy to the strcuk object when the striking object rebounds. Conservation of momementum demands it. On the other hand, that's based on "inelastic" objects and and when there's deformation then things are calculated differently.
Maybe the deformation is what you're after, rather than kinetic energy transfer. I've been away from the math of physics for too long to figure out or remember how this translates for instance into driving a tenon into a mortise or other common tasks. I'm sure one of our engineer participants will address this soon enough. :)
Buy one here and you'll have enough money left over to get 4 pounder too.
and don't forget your free worklight, screwdrivers, and tape measure while you're there.
I'd bet even money that the HF model is identical to LVs except for color.
But you have ended up with a sledge hammer, not a dead blow.
A proper dead blow transfers all its force and no bounce back. You can hit it as hard as you can on a concrete floor and it just "sits" there.
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"Limit one FREE coupon per customer per day."
You just contradicted yourself. There is *not* a greater transfer of energy if the hammer rebounds. The energy required for the rebound is not imparted to the object, which is sorta the purpose of striking it in the first place. There is no such thing as conservation of momentum, in this case. There is *always* conservation of (matter and) energy.
Deformation is kinetic energy transfer. You're converting the kinetic energy into heat (still kinetic energy with perhaps some potential energy in a chemical/physical state change).
It all turns into heat. ;-) You're trading the kinetic energy from the hammer into heat from friction (heat/kinetic energy) of the mortise into it's tenon.
wrote
What he said. Where did the energy for the mallet come from to make it reverse direction. From the object being struck not soaking up all the energy. Been saying that all along.
This horse is about dead, isn't it?
That said, because it doesn't rebound doesn't mean that it did its job, either. If the energy is absorbed in the hammer's head (heat), it's not doing much good either. Of course, if it dents the paint on your just completed cherry table, it isn't doing its job either. ;-)
You're supposed to put the glue on the tenon _before_ pounding it into the mortise.
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