What do you guys think about agitating your quench bucket?

jhiggins said:
So what would be a good circulation pattern inside the tank, Mike? Are you saying a whirlpool effect is good? I would think that a 5-gallon container with a slow-spiraling whirlpool would be quite effective. You could quench the blade toward the side of the whirlpool, facing the edge into the current. Does that sound okay, or too technical for simple quenching?

What about a different pattern of circultation, like from bottom to top in a "turnover" pattern?

BTW, Rene: Great topic! Thanks!
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Actually a " turnover" is what my oil does as its heating. But I prefer it not moving. A long,wide, thin blade and movement don't go well together. If I need to agitate the oil or the blade then I think there are some quenching issues that need to be addressed. Movement in any way while in the quench leads to incosistancies from blade to blade; in my opinion. BUT; we each do it our own way in our own shop with our own little ideosyncracies.
I want 140 deg. still oil. Do what works for you.
 
mete said:
You shouldn't have to 'draw the oil off the top'.A pump placed near the bottom will force a column of oil to the top and you will be setting up circulation of up in the center and down the sides .You lower the knife into the center of the rising column.
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Hmmm... that makes sense, but I was thinking of maybe an external pump. That would keep the pump motor cool. The only drawback would be in over-engineering a way for the quench to dribble over the sides and into a secondary sump for the pump to draw from. Sounds like too much work! LOL!

But... a pump feeding directly into the center of the bottom of the quench tank, forcing up a column of fluid, with a drain near the top to maintain the level would probably work fine. Looks like I'll have to do some experiments. It would be nice to have a setup in which there were actually two containers of quench. One would be where the quench medium is being conditioned to the correct temp, then pumped to the second where "The Magic" happens.

Whattya think, guys? Too complicated?
 
Sounds like over-engineering for sure. :D

Mike Williams has made a couple of posts in this thread that seem to be being overlooked. I'd suggest at least pondering on what he's saying a bit.

The description that Mike gave of his tank sounds very similar to my hotwater heater quench tank (posted in another thread). The convection action of the oil off the heating elements in the bottom of the tank creates a gentle movement that you can see. It's a slow, gentle, even roll. You don't really need a lot of movement. In fact, I imagine that a lot of movement has the potential to do more harm than good.

All you're doing is breaking the insulating vapor jacket that can surround the blade when quenching -- right? You don't need a high rolling boil, a geyser, or a whirling tornado. You can also break the vapor jacket by simply doing an interrupted quench.

Don't get me wrong. I'm not knocking the idea of a circulating pump. Just keep in mind that this is a situation where just because a little can be good, a lot won't necessarily be better.
 
I would like to vote for quenching blades without any side swishing because of something I have learned in gunsmithing.
I have made a good number of bullet cherries and chamber reamers over the years and I lack the means to grind them after heat treat. One of the best ways to warp a reamer is to simply heat and quench it like we do a knife blade. BUT there is a way to keep them straight enough to use without grinding.
I now set them in a drill press running at rather high speed and heat them with a torch and when at temp I lift the quench from below. Of the hundreds I have made I have yet to make a bent one by this method.
I think you can see that this is the same as quenching a blade edge first and not swishing it side ways.

I also have built oil heated wax tanks and heated our wax injectors with water heating elements and have not had to replace an element in machines that have run round the clock for more than 25 years. In the begining I did install large relays to fire the heaters so that my small temp.controller points would not soon burn out.
I guess my thoughts would be to curculate the oil in between blades just to bring the top and bottom to a uniform temp.
Good luck with your projects.
 
WHIRPOOL quench. Actually It was in reference to the "washing machine pump"

Keeping a slow stream past the blade was my idea.
Plumbing. A couple nipples on the outside of the tank, plumbed to the pump, should keep it moveing. One outlet one inlet, about 90d. apart I'm thinking.

Yeah I can see the rise of oil from the heating elements, I hadn't thouight that would be enough movement.

I don't do any side swishing of my blades. A little up and down though.

Tai Goo, gets some Way KEwl temper lines with his Vibration quench tank.

Plastic tank, 3/8" drill with a bent 1/4" rod bar taped to the side to provide the vibrations.

I guess that's as close to an "agitated quench tank" as you can get.


small agitated tank
 
Mike (Sweany),
The more I think about it, I should have said that I was "under the impression" that the gentle movement was enough. I don't want to come off like some kind of resident expert, because I'm not.

I use an interrupted quench, even when using the hotwater heater quench tank.

By the way, I've seen some of those Tai Goo blades that were done in the vibrating quench. Pretty cool stuff.
 
Terry I dunno either. Just going on what a friend of mine told me. They used to quench pallet loads of wrenches at once. He said they had a pump on it to keep the oil moveing.

I know,there is big diffrence between a blade and 500 lbs of hot steel. But he thought it was worth pursueing.

the commercial guys must know something
 
There seems to be much opinion on both sides of this issue. And has been said it is what works for the indivual that really counts. So I guess I will give the method that seems to work best in my shop. As I often find, I must admit to be in agreement with mete on the topic. I work mostly with the salts and they will absolutely work better with as much even agitation as you can give them. When I work with oil, I always agitate the blade in a tip to tang direction in the quench. I have gotten very consistent results for many years now. I myself would hesitate to blindly follow all the literature I have encountered on the topic, since, as has been mentioned, industry often has different requirements than the lone knifemaker. However my experience has shown me that industry may know what it is talking about on this one, at least in my shop.

There are many legitimate reasons for not tempting fate on the quench, to be sure. But the principals behind the movent of either the blade or the quench medium, are also good for providing even, consistancy in the quench. It all has to do with the dreaded vapor jacket phase of the quench. Gaseous bubbles and pockets lead to uneven cooling which can result in distortion or even soft spots, if things are bad enough. Agitation helps defeat the vapor jacket and keeps the cooling even. Improper agitation in the final, liquid cooling stage could result in distortion, but all of my blades are out of the oil by then anyhow. So I have to say that in my shop, agitation has given me better results and more consistancy. But it is not uncommon to have radically different results from shop to shop in this business. Quite a bit of this could also depend upon the quenching medium.
 
one other thing my my HT buddy mentioned useing was an air pump and bubbles, sounds easier to control, easy to contuct, a ring of copper tubeing with holes drilled in it.

But would air injection have a detrimental effect on the oil??
 
primos said:
Sounds like over-engineering for sure. :D
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Yeah, that's me alright, Terry. I'm always trying to over-engineer something to "dummy-proof" it. Comes from my years in machine process and production. I've always tried to eliminate aas many variables as possible. Hard for me to back off and accept the fact that an old water heater sawn in half just might make a darn good quench bucket! Good advice!

Mike Sweany: See what you get me into? Whirlpool quench indeed! Slap yourself for me, will you? :D :D :D
 
The shoe shank factory I worked in as a tool and die maker
used an atmospheric generator oven and the steel was dumped from it into the
quench with a live chain conveyor belt moving the steel threw it up and out.
 
Haven't been up completely on this good thread. It makes sence to me that circulating the oil from bottom to top provides reasonable consistance in oil temp. throughout and that convection transfer alone will not do that because there will be a difference in depth temperatures (that closest to the heating source will always be warmer regardless of convection).

Because I do not yet have a pumping system I attempt to make up for it by stiring the oil manually just prior to quench but soon enough before to monitor final temperature.

RL
 
Hey Jeff, guess you could just stir it with a stick. Simple,low tech. easy enough for anybody to run.
I'll slap myself in the morning, that's when I'll need it. :p :p :p :p

So how about I rig a pump, and really fine spray showerhead........... :rolleyes:
 
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