Heat treat furnace

[Highpower]

Thanks guys.

Mike, I would love to see what it is you are working on. I have another project in mind and it's always nice to get a different perspective from other peoples work and way of doing things.

dallen has something in the works too and I'm looking forward to getting some new idea's.

I already know what my first test subject will be in the "new to me" furnace. All I have to do is get around to finish machining it! It's actually what I was working on before I got sidetracked (again) with a furnace that fell into my lap......  

I bought a couple of chunks of 4140 a couple years ago it seems like to make a new ratchet for my 3-1/2 ton arbor press.
The original cast iron part has got to go.

   

[Highpower]

(12-05-2015, 09:03 AM)RobWilson. Wrote: PS you probably know this but others may not , stick a few bits of charcoal in the furnace with your part , it uses up the oxygen in the furnace chamber as it burns  and so cutting down on the scale/oxide   on parts ,its not a perfect solution but it is an improvement. Keep the door shut as much as possible .

Rob,

Is there a 'rule of thumb' for deciding how much charcoal you add in with your part?
"A few bits" leaves it open to a pretty wide range of interpretation.....

I've seen it suggested a few times to add a piece of char cloth in with a part if you are wrapping it in stainless 'foil', but again I'm not clear on how much is 'just enough'.

Fortunately I was a boy scout, so at least I know what 'char cloth' is......

[Roadracer_Al]

Not that I'm a heat-treat expert, but on the few knives I've done with stainless foil, I have put a piece of newspaper about the same size as the blade into the foil. IMHO, you probably can't put too much in as it will simply consume the oxygen until it's gone then just char. I doubt that you can significantly add carbon to the steel by using a slip of newspaper, but that you could with a charcoal dust pack.

[RobWilson]

Hi Willie 


  , yes thinking about it ,my "few bits" description is a tad subjective  ,sorry   , a few bits the size of a cherry   , few being more than 2  but less than 4  


Char Cloth will do the same thing , anything that uses up the Oxygen and does not add other gasses to the chamber environment , dead Carbon based lifeforms work well . 



I will be doing your mod to my furnace , but with the lazy Englishman setting 


Rob

[PixMan]

(12-14-2015, 05:51 PM)Highpower Wrote: Thanks guys.

Mike, I would love to see what it is you are working on. I have another project in mind and it's always nice to get a different perspective from other peoples work and way of doing things.

dallen has something in the works too and I'm looking forward to getting some new idea's.

I already know what my first test subject will be in the "new to me" furnace. All I have to do is get around to finish machining it! It's actually what I was working on before I got sidetracked (again) with a furnace that fell into my lap......  

I bought a couple of chunks of 4140 a couple years ago it seems like to make a new ratchet for my 3-1/2 ton arbor press.
The original cast iron part has got to go.  

I would love to give my dividing head some exercise making that piece for you! My  lathe, arbor press and broaches would also get some needed exercise.

[Highpower]

(12-16-2015, 01:49 PM)RobWilson. Wrote: ...... few being more than 2  but less than 4  

Too funny Rob. That is exactly the way it works, as my wife tells me. We used to do battle over those terms sometimes. But she informed me that a "couple" means 2, and a "few" means 3! Been that way ever since....

Quote:I will be doing your mod to my furnace , but with the lazy Englishman setting 

Rob

That's OK Rob, I won't hold it against you.

You will be happy to know that the Englishman setting was the "default" on my controller and I'm sure it will be on yours also. But you know me.... always going off and tilting at windmills.

[Highpower]

(12-16-2015, 01:51 PM)PixMan Wrote: I would love to give my dividing head some exercise making that piece for you! My  lathe, arbor press and broaches would also get some needed exercise.

I appreciate the offer Ken but I have already done the lathe work and was looking forward to getting in some practice myself with my dividing head. It's been awhile. I was actually setting it up on the mill when my buddy Sean called me and asked if I would be interested in getting a furnace....  

The one thing I will have to work around is the fact that I don't have a 10mm broach. I have all kinds of imperial broaches, but not one metric.  

I bought a second slug of round stock to make a bushing for the 3/8" broach to start with, and then will open it up to 10mm using my "ArmStrong" shaper. (Mill quill and a square tool bit.) That's been the plan anyway.

Good excuse for me to hide out in the basement this weekend.  

   

[f350ca]

How about a stepped key Willie. 10mm to fit the shaft and 3/8 to fit your keyway.

[Highpower]

(12-17-2015, 01:42 PM)f350ca Wrote: How about a stepped key Willie. 10mm to fit the shaft and 3/8 to fit your keyway.

I'm pretty sure we discussed that awhile back in a different thread Greg, but I don't remember what the consensus was on the strength of a stepped key in this instance.

Hmmmm.... I'll have to go back and find that.

I was probably given the answer and forgot about it already. Thanks for bringing that up again Greg!

[f350ca]

If your worried about strength cut the keyway in the ratchet 1/2 and step down to 10 mm with the key