Synthetic motor oil

M

M forge

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May 27, 2011
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I searched the forum and did not find a lot on the subject so forgive me if I am asking something again.

Do any of you use sythetic motor oil as a quech oil. I know regualr quench oil designed for the type steel you are using is best, but I haven't gotten any yet, and don't really know what one would be best for 52100 that is readialy available. I used some new 20W-50 sythetic motor oil to quench some 52100 and got pretty decent results. Does anybody else use it and what kind of results do you get.

Thanks for your help.
 
I have ruined some blades with ATF.
This horse has been beaten badly.

If you're not going to use an engineered quenchant, use Canola oil instead of the nasty motor stuff. It works well for several types of steel and is not foul to deal with, much higher flash point, no toxic fumes, etc. Preheat to ~135F.

-Daizee
 
I use Mobil 1 for hand sanding but not for quenching. It is actually cheaper to buy 5 gal of Parks 50 or AAA than 5 gal of synthetic motor oil.

That being said, if it works for you then use it. But I wouldn't rush out to buy any when I can get the right oil for cheaper.
 
I am going to get some real quench oil, but I also need to get/build a real quench tank. I am using bread pans right now. One hold 1 quart and the other holds 2 quarts so the expense was not that great as I just got 2 quarts. I was using drug store mineral oil and got poor results. I use 5160 and 52100. I did get 159 cuts on 3/4" rope with the blade I used the synthetic oil on, so that is a big improvement. I look forward to seeing the reuslts once I get a real tank and quench oil.
 
A gallon paint can filled with canola will be a far better idea.
One or two quarts of any oil will only quench a small blade.

Gallon of canola plus used pail = about $13-15.
Two quarts synthetic oil plus old bread pan = $15-20
 
Before I started using Houghton Mar-Temp 355 to quench my A-2 in, I used Mobile One Extended Performance motor oil. The thing about the synthetic oils is that temperature doesn't affect their viscosity, for better and for worse.
I almost forgot to mention, it is really SLOW. My A-2 blades did really well in it.
 
Motor oil is too viscus for good results. Quench oil is quite thin. Thick oil has poor convection so you get a slow quench with large heat gradients which leads to warping and inadequately quenched steel. Plus it has detergent additives and other things that create bubbles and also burn and stick to the blade.

This horse has been beaten dead. If you're not going to get an industrial quench oil, you should get yourself some canola oil, it's cheaper and less toxic. And smells like french fries.
 
there was a guy I talked to on Knifetalk forums that used syn motor oil and was getting some pretty good results.

I was using vet grade mineral oil from a local farm and ranch store and getting good results, swithced to texaco type a, and am getting better results with 52100

At the risk of being a contrarian {big word I know} I dont believe it is so much the oil, or the equipment, but the knifesmith that makes the biggest difference, and his dedication to performance. If syn motor oil is what you have available, use it. and TEST IT which you are doing. I personally believe that it is the bladesmiths dedication to performance that makes a good blade, not his tools.

Of course, you could make 2 blades, as close as you can to being the same, quench one in syn motor oil, and one in canola, see which one cuts better, and which one does better it the edge flex test and the blade flex test. use the quenchant that gives the best results till you find something that does better.

I just repaired a philipino machete that came into the shop. fella said his dad got it there when he was stationed there as a marine over 50 years ago. looks like all hand work with a file after the forging. Can almost guarantee that that smith didnt use comercial quenchant, or a grinder, or a drill press. After I put an edge on it, that blade would cut really well, and after 50 years in service has held up beautifully.
 
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Canola oil is the best choice besides quench oil for this steel, its cheap and you will get noticeable better results with it then motor oil. I noticed my 5160 blades coming out of the canola oil harder then when they came out of the motor oil
 
Thanks for all the help guys.

While we are on this subject, what kind of cutting results should I expect? I know there are many variables, but lets say we have a 5160 or 52100 blade with a high flat grind 3 1/2" cutting edge. How many cuts on 3/4" rope would you expect to get? Just curious as I am trying to develop my skills and need something to shoot for.
 
M forge said:
Thanks for all the help guys.

While we are on this subject, what kind of cutting results should I expect? I know there are many variables, but lets say we have a 5160 or 52100 blade with a high flat grind 3 1/2" cutting edge. How many cuts on 3/4" rope would you expect to get? Just curious as I am trying to develop my skills and need something to shoot for.
Click to expand...

First of all, the 52100 blade, generally speaking, will out slice (cut rope) better than the 5160 blade, since it's a hypereutectoid steel, w/ some carbide action going on.
As far as how many cuts on rope, I'm sure Ed Fowler would love to discuss it with you. :)
 
My first thought is how toxic synthetic motor oil fumes are? When quenching we breath in a lot of fumes and it is all but impossible to keep away from them. Quenching oil with a lot of additives can change with each blade.

When I read about makers using what I consider odd ball steels and quenching oils coming down with various cancers I pay attention and am glad I have stayed away from them.

I have only used two quenching oils, Brownells Tough Quench when I was doing Damascus and Texaco type A for 5160 and 52100. You will be in the ball park with an 18 second oil.

From what I have read one gallon of oil is enough to handle any heat load from the blades we make, my largest was 9 inches long 2 inches from spine to edge that blade cut well and passed all tests.

As has been mentioned edge geometry is a very significant variable when it comes to cut.
 
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