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#42 ·
torkas said:
with 20 micron diamond paste it will take a while I guess...
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Not necessary. Just lapped mine Deepfire 6.02. Two evenings of handjob and it shines:D Started with 20 micron diamond paste, then 10, 5 and 5-3 (wanted 1 micron, but seller mixed it).

You really do not need a machine for that. Though good sturdy rod would help to lap faster. I used standard barrel cleaning rods that came with my rifles and broke two of them.
 
Discussion starter · #43 ·
Speedle said:
Not necessary. Just lapped mine Deepfire 6.02. Two evenings of handjob and it shines:D Started with 20 micron diamond paste, then 10, 5 and 5-3 (wanted 1 micron, but seller mixed it).

You really do not need a machine for that. Though good sturdy rod would help to lap faster. I used standard barrel cleaning rods that came with my rifles and broke two of them.
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In this kit there is brass rod, which is stiff enough I think. Better than acrylic rod.
 
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#45 · (Edited)
I build a rod out of a M4 threaded steel bar and coated it with a heat shrink tube.
It's durable as f**k, difficult to bend and was made for under 3€
My stock one just broke while lapping my VSR barrel.:ashamed:
 
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#47 ·
newcomer said:
CHF is actually much superior to extrusion in terms of straightness and strength(grain structure). Extrusion is the cheapest and fastest method to produce wonky tubes.
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Extruded tubes can indeed bend, but they have a very even surface unlike CHF which can be more irregular. And modern techniques produce pretty straight extruded tubes without much bending really. I'd say extrusion is better suited for airsoft barrels.

It's also cheaper.

CHF indeed is stronger due to the work hardening, but honestly how much of an influence does inner barrel strength have anyway? It's mostly about surface durability and straightness.
 
#48 ·
Both extruded and CHF barrels (for airsoft) would need to be undersized then reamed to the final ID. Neither process in and of itself will cause irregular straitness. So long as the blank barrel is oversized on the OD, and the ID is reamed strait, putting it on a centering chuck of a lathe should yeild a uniform OD using the ID as a reference.

Based on the RS industry, CHF is similar to injection molding in regards to price. It is expensive for tooling and start up but afterwards the individual unit costs are drastically reduced. Benefits to CHF, you can use cheap(er) metals. There is nothing inherently wrong with CHF methods so long as the follow up work is done correctly, same goes for extruded. The other benefit I see in regards to CHF is that the ID must be oversized to fit over the mandrel where extruded must be oversized. After the CHF forming it may also be possible (if it is like firearm barrels) to get closer to the final OD, meaning less time spent turning down and material to be removed which leads to extended tool life.

Sent from my SM-N910V using Tapatalk
 
#49 ·
Reliku said:
Cold hammer forged barrels are not better.

Cold hammer forging is when you put a barrel blank on a rod, squeezing is through a bunch of presses which repeatedly hammer it into shape, blow by blow. It's a pretty violent process and by no means the most accurate one.

Extrusion is where a piece of material (in this case metal, either hot or cold depending on hot or cold extrusion) is squeezed through a die by a hydraulic press. It is not hammered violently, instead it is a rather smooth process. This is much better for accuracy.

The main disadvantage of CHF is that the barrel may be straight overall, but the inside will not be as straight everywhere because it is continuously hammered from the sides during the process. This definitely has an effect on accuracy. Extrusion doesn't have this problem as the forces aren't exercised from the sides of the barrel and it's a smooth, continuous process.

One more reason why EdGI barrels are better than PDI :yup:
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Pardon me for the late reply, but you are incorrect. Very, very incorrect.

Extrusion is the equivalent of the Play-Doh spaghetti maker. The material is pushed through the die to create the same shape of the die.

This is not a good method to use. It can create inconsistent straightness and inconsistent bore diameter.

Cold hammer forging, on the other hand uses hammers to apply pressure onto a tool that is inside of the barrel. This creates a very even barrel straightness, and the bore of it is much more consistent as well. It actually results in a polygon with 1000 sides, but that is still better than a deformed circle.

You can ask whoever you'd like. Cold hammer forging is better. I was curious myself and decided to ask careful, to which he said that cold hammer forging IS a better way of doing it, but they are both pretty bad ways of making a smooth cylinder.

And EdGi is NOT cold hammer forged. EdGi brass is extruded, and EdGi steel is made from gun drilled blanks which are better than cold hammer forging.
 
#50 ·
Pardon me for the late reply, but you are incorrect. Very, very incorrect.
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You have a thing for disagreeing with everyone, lol.

Look up a video of the CHF process, the blows are not applied on the inside, but on the outside. It makes for cheap but irregular barrels, the big advantage is that it's fast to produce.

Extrusion is by no means perfect either but it's a smooth process which means no irregular dents all over the place.

Extrusion is the equivalent of the Play-Doh spaghetti maker. The material is pushed through the die to create the same shape of the die.

This is not a good method to use. It can create inconsistent straightness and inconsistent bore diameter
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Straightness, yeah, but modern stretching techniques mostly fix that. Diameter, no, extrusion actually does that pretty well. Slight deviations don't matter since it's lapped anyway.

And yeah, it is the equivalent of a spaghetti maker, but that does not mean extrusion produces products of poor tolerances. Especially surface consistency is very good with extruded or drawn things.

Which happens to be one of the most important properties of an inner barrel :yup:

I'd say extrusion is better suited than CHF, but honestly, who cares? Finishing (lapping & crowning) is what really matters lol :hehe:
 
#51 ·
No, I have a thing for disagreeing with people who are wrong.

I realize they are applied on the outside. How would they be applied on the inside?

They're not irregular. They are straighter than extrusion.

It is a 1000 sided polygon, and if you take into account that the diameter is 6 mm or so, you'll realize that it's pretty accurate.

Extrusion can be more oval shaped and not as spherical.

And the POINT of me saying PDI was better for lapping was because it was cold hammer forged.. So when you say that finishing matters more, that's irrelevant as the whole topic was on how to finish the barrel well.
 
#52 ·
Extrusion is more spherical than CHF, unless a poor quality die was used.

With CHF the blank is hammered from the sides. This never creates a consistent thickness, whereas extrusion is a smooth process, pressure is constant, thus more consistent.
 
#56 ·
before I really like to do lapping, but can't get proper tools for do it. So I just gave up and buy good aftermarket inner or use best bucking can find.


save more time and work .
 
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