Need help bending ak flat

[rdb241]

Speaking of heat treating...

You need to know what kind of steel the part is made out of before you decided to heat treat. Low carbon steels cannot be heat treated, but they can be surface hardened by adding carbon to the solid solution.

As far as putting brake fluid and gasoline... that's more like case hardening, but you are probably not getting anywhere near the temperatures required to change the crystal matrix, and even if you are, they are not maintained long enough to really have any effect. A typical annealing run would take you up to nearly 2000F for several hours, followed by a long furnace cooling process.

Surface hardening of the steel can be achieved by heating the whole part up to approximately 1200-1800F (depends on alloy) and then quenching in oil. I have heard some people using a technique called a "superquench" which uses high temperatures, followed by a water bath full of surfactants to very quickly carry heat away.

Before you get carried away determine what the blank is made of, if it is made of 1018 mild steel forget heat treating. If it's made of A36 (a common structural steel it is treatable). Also, common grades of alloy steels are the 4000 series (4130 et al).

If you do decide to send this out for heat treating, you want hardening, followed by tempering. This will guarantee your reciever will be tough, and not just hard. I strongly recommend a shop for this, as doing it improperly can warp the part and ruin all the good work you just did.

I seem to have had no problems with my technique. I have done a dozen now and they all function and work just fine. No warping, no nothing.

 

[bassman2]

If you search - there are some very good step by step instructions online with pictures! There are some additional (2nd step) methods for heat treating and annealing. I used a torch and then a high temp oven.

AK builders stuff is top notch.

Bending the flat is the easy part - (with the right tools) You'll spend most of your time fitting the top rail to the bolt carrier.

If you want a really good looking AK - blast the finish off of the parts and Re-Parkerize the entire thing - then duracoat it. Then your receiver will match the rest of the rifle.

 

[AMProducts]

I seem to have had no problems with my technique. I have done a dozen now and they all function and work just fine. No warping, no nothing.

Yes, because you're not getting it hot enough to accomplish anything. I did a little reading, it seems most of the flats from tapco are 4130 alloy steel, which is hardenable, they also come in an annealed and tempered state, so a second anneal is not going to buy you much, you're not working the metal enough for work hardening. What is probably happening is the soot left behind acts as a lubricant for the rest of your processes.

I think your techinique is fine, I'm just trying to shed light on what is actually happening. To be axiomatic, if it's stupid, but works, it's not stupid.

If you want some great info on this type of steel:

<broken link removed>

While it doesn't give specific soak times here's the approximate heat treating process:

Heating at 1600 F followed by an oil quench will harden the 4130 alloy. For best results a normalizing pre-hardening heat treatment may be used at 1650 to 1700 F followed by the 1600 F soak and oil quench.

Annealing is handled by this process:

4130 (and most of the other low alloy steels) may be annealed at 1550 F for a time long enough to allow thorough heating of the section size. It should then be cooled in the furnace at a rate of less than 50 F per hour down to 900 F, followed by air cooling from 900 F.

Also, for those of you who are interested, I have spent most of this evening parkerizing stuff. I did a little write-up of it over in the gunsmithing section.

 

[rdb241]

Yes, because you're not getting it hot enough to accomplish anything. I did a little reading, it seems most of the flats from tapco are 4130 alloy steel, which is hardenable, they also come in an annealed and tempered state, so a second anneal is not going to buy you much, you're not working the metal enough for work hardening. What is probably happening is the soot left behind acts as a lubricant for the rest of your processes.

I think your techinique is fine, I'm just trying to shed light on what is actually happening. To be axiomatic, if it's stupid, but works, it's not stupid.

If you want some great info on this type of steel:

<broken link removed>

While it doesn't give specific soak times here's the approximate heat treating process:

Heating at 1600 F followed by an oil quench will harden the 4130 alloy. For best results a normalizing pre-hardening heat treatment may be used at 1650 to 1700 F followed by the 1600 F soak and oil quench.

Annealing is handled by this process:

4130 (and most of the other low alloy steels) may be annealed at 1550 F for a time long enough to allow thorough heating of the section size. It should then be cooled in the furnace at a rate of less than 50 F per hour down to 900 F, followed by air cooling from 900 F.

Also, for those of you who are interested, I have spent most of this evening parkerizing stuff. I did a little write-up of it over in the gunsmithing section.

Thanx for the great info........

 

[rdb241]

AK builders stuff is top notch.

Bending the flat is the easy part - (with the right tools) You'll spend most of your time fitting the top rail to the bolt carrier.

If you want a really good looking AK - blast the finish off of the parts and Re-Parkerize the entire thing - then duracoat it. Then your receiver will match the rest of the rifle.

I just placed another order with Curtis this morning. Yes his stuff is aircraft quality tooling. Almost fool proof. You are so right about fitting the top rail. That does take the most time if you are careful when you do it. I prefer to file and fit by hand and not with a Dremmel. When I was done with mine I did exactly what you did. Blasted it and finished it off with Duracoat.

 

[caden08]

what do you mean by blast it? And let's say I wanted a new coat of flat black on everything. How would I strip the barrel and other components? My build is on a little freeze been way to busy at work the last to weeks.

Also is there any local shops that sell duracoat? I couldn't find a retailer off their website. I'm thinking larz larson pink for this build

If you search - there are some very good step by step instructions online with pictures! There are some additional (2nd step) methods for heat treating and annealing. I used a torch and then a high temp oven.

AK builders stuff is top notch.

Bending the flat is the easy part - (with the right tools) You'll spend most of your time fitting the top rail to the bolt carrier.

If you want a really good looking AK - blast the finish off of the parts and Re-Parkerize the entire thing - then duracoat it. Then your receiver will match the rest of the rifle.

 

[rdb241]

what do you mean by blast it? And let's say I wanted a new coat of flat black on everything. How would I strip the barrel and other components? My build is on a little freeze been way to busy at work the last to weeks.

Also is there any local shops that sell duracoat? I couldn't find a retailer off their website. I'm thinking larz larson pink for this build

Whatever on the gay color....try this for your Duracoat needs

Duracoat Desert Mirageflage

 

[rdb241]

i just placed another order with curtis this morning. Yes his stuff is aircraft quality tooling. Almost fool proof. You are so right about fitting the top rail. That does take the most time if you are careful when you do it. I prefer to file and fit by hand and not with a dremmel. When i was done with mine i did exactly what you did. Blasted it and finished it off with duracoat.

 

[caden08]

That's sweet! Can I only order online or do they have any retailers localy. I'm sure with the specialty stuff like yours I would have to order. On the fixed stock did you use a synthetic stock or a is that wood?

 

[rdb241]

That's sweet! Can I only order online or do they have any retailers localy. I'm sure with the specialty stuff like yours I would have to order. On the fixed stock did you use a synthetic stock or a is that wood?

I don't think there are any retailers in the northwest. I ordered mine on line. The fixed stock is a US made synthetic Tapco stock for a compliance part.

 

[Ewald]

Just for referance for builders. Here are 2 forums that are the place to go for AK info. <broken link removed>
The AK Files Forums - Gunsmithing & Build It Yourself

Lots of info, links, videos, step by step you name it.