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Link Posted: 1/25/2022 8:40:35 AM EDT
[#1]
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Quoted:
You won't always see a gate mark on some parts that have secondary machining because it is placed where it gets removed during machining.

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This.
Link Posted: 1/25/2022 8:45:24 AM EDT
[#2]
My question is, how do you tell a gate mark from a cut off sprue?
Link Posted: 1/25/2022 10:55:09 AM EDT
[#3]
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My question is, how do you tell a gate mark from a cut off sprue?
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Probably can't always but the size, area, and visual appearance of attachment might be one thing to look at.
  If you look at the videos on the cast parts they are cut off a solidified metal tree. Most of the AR parts I have seen that showed the attachment to the center tree has a large surface used to attach it like the end face of the trigger, the end of a selector, the extended face of the hammer, and the end of the bolt catch. They are cut off the solid metal tree leaving a large flat area that is later removed or smoothed.
 Some videos show the MIM parts that are made on trees being more like the plastic injected parts attached to something like a plastic model car or plane kit arrangement with small attachment points. Also in the MIM videos I watched the parts are removed from the small attachment to the trees before they go through the processing and shrinking of the part. Sometimes removal was done by machine and by hand in one video I watched.
Link Posted: 1/25/2022 6:28:30 PM EDT
[#4]
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I just don't understand how someone can look at a part and tell if it was cast or injection molded.
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The same way a Skilled Machinist can look at two pin gauges that are .010 different in size resting on a work bench, and tell you by looking which is smaller/larger.


MIM parts often have different external features than cast or billet parts with the same function.
Link Posted: 1/27/2022 2:36:03 PM EDT
[#5]
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The same way a Skilled Machinist can look at two pin gauges that are .010 different in size resting on a work bench, and tell you by looking which is smaller/larger.


MIM parts often have different external features than cast or billet parts with the same function.
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I’m going to have to toss the BS flag on that first part. I are a skilled machiner and work with a bunch for the last 20 years and if one can tell you the difference between a 1/4” and 6 mm dowel pin have him repeat the feat. You will soon learn it was just dumb luck.
Link Posted: 1/27/2022 5:33:35 PM EDT
[#6]
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Very interesting, I had always assumed the spec would call for forged, I did not realize it was investment casting. Thank you for that clarification. Lots of good information has been shared here!

I took a real close look at the Anderson kits I have, I have come to the conclusion they are indeed MIM on the fire control group, bolt catch, mag catch, and safety. All have the tell tale "injection port." I took some pictures, my phone is old though so they aren't the best but I think you can see what I'm talking about.

The parts in question
https://imgur.com/1lLFB0s.jpg

This is the mag catch, I think this was the best picture I got of the injection site.
https://imgur.com/ubtdgFy.jpg

Here's the hammer with the same sort of site.
https://imgur.com/HS3RJ8Q.jpg

All of them have a similar spot on them that would be where the powdered metal is injected into the mold as I understand.
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@ihv800

Here's the scoop....

"The triggers and hammers are MIM parts made of S7."

I should have the disco and bolt catch info in a few days.

This is straight from the horse's mouth.  
Link Posted: 1/27/2022 5:40:36 PM EDT
[#7]
Back in the good ole days someone had a sale and Complete Anderson parts kits were like $7. Think I bought a dozen of them. Out of those dozen I think o was able to cobble like 4 complete kits that could actually function.
Link Posted: 1/27/2022 6:20:37 PM EDT
[#8]
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I’m going to have to toss the BS flag on that first part. I are a skilled machiner and work with a bunch for the last 20 years and if one can tell you the difference between a 1/4” and 6 mm dowel pin have him repeat the feat. You will soon learn it was just dumb luck.
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That would be easy, put them end to end. One is .014" higher and you can feel it, don't need to see it.
Link Posted: 1/27/2022 8:25:53 PM EDT
[#9]
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Quoted:


@ihv800

Here's the scoop....

"The triggers and hammers are MIM parts made of S7."

I should have the disco and bolt catch info in a few days.

This is straight from the horse's mouth.  
View Quote


A concrete answer! Thanks for that. I'm guessing S7 is some sort of tool steel?
Link Posted: 1/27/2022 8:30:23 PM EDT
[#10]
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A concrete answer! Thanks for that. I'm guessing S7 is some sort of tool steel?
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Correct.

S7 Shock-Resisting Tool Steel is an air or oil hardening tool steel that is characterized by very high impact toughness
Link Posted: 1/27/2022 8:35:57 PM EDT
[#11]
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Quoted:

Correct.

S7 Shock-Resisting Tool Steel is an air or oil hardening tool steel that is characterized by very high impact toughness
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Quoted:
Quoted:


A concrete answer! Thanks for that. I'm guessing S7 is some sort of tool steel?

Correct.

S7 Shock-Resisting Tool Steel is an air or oil hardening tool steel that is characterized by very high impact toughness


You're killin' me, brother!  So, this is powdered S7 with some binding glue, squirted into a mold?  I have seen other parts and tools made from S7, but never a MIM.

Did I read the above post correct?  Do you have some MIMzies inbound for a torture test?
Link Posted: 1/27/2022 8:42:34 PM EDT
[#12]
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Quoted:


You're killin' me, brother!  So, this is powdered S7 with some binding glue, squirted into a mold?  I have seen other parts and tools made from S7, but never a MIM.

Did I read the above post correct?  Do you have some MIMzies inbound for a torture test?
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:


A concrete answer! Thanks for that. I'm guessing S7 is some sort of tool steel?

Correct.

S7 Shock-Resisting Tool Steel is an air or oil hardening tool steel that is characterized by very high impact toughness


You're killin' me, brother!  So, this is powdered S7 with some binding glue, squirted into a mold?  I have seen other parts and tools made from S7, but never a MIM.

Did I read the above post correct?  Do you have some MIMzies inbound for a torture test?

100% MIM S7, boss.

And negative, I swore off Anderson LPKs a long minute back.
Link Posted: 1/27/2022 8:47:55 PM EDT
[#13]
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Quoted:

100% MIM S7, boss.

And negative, I swore off Anderson LPKs a long minute back.
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Quoted:


A concrete answer! Thanks for that. I'm guessing S7 is some sort of tool steel?

Correct.

S7 Shock-Resisting Tool Steel is an air or oil hardening tool steel that is characterized by very high impact toughness


You're killin' me, brother!  So, this is powdered S7 with some binding glue, squirted into a mold?  I have seen other parts and tools made from S7, but never a MIM.

Did I read the above post correct?  Do you have some MIMzies inbound for a torture test?

100% MIM S7, boss.

And negative, I swore off Anderson LPKs a long minute back.


Copy.  

I am truly starting to wonder how many MIM parts we have been receiving without knowing.

You and I went over this a few years back when I got those fucky PSA kits, I tossed them for being shit, but it never crossed my mind they were MIM.  I am now betting they were!

Link Posted: 1/27/2022 8:57:00 PM EDT
[#14]
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Quoted:


Copy.  

I am truly starting to wonder how many MIM parts we have been receiving without knowing.

You and I went over this a few years back when I got those fucky PSA kits, I tossed them for being shit, but it never crossed my mind they were MIM.  I am now betting they were!

View Quote

Yeah...I received some interesting trash a few times as well. Haven't been back since.
Link Posted: 1/27/2022 8:59:25 PM EDT
[#15]
Mim is faster and cheaper than cast. The mold is permanent like plastic injection mold. It can be a good product if done properly, but the chance of inferior parts is higher than a cast part. Under no circumstances is it better than cast. If a cast part if bad, there are visual defects you can easily see. I do casting. With MIM, If the binder is not cooked out properly and all the small particles do not melt-bond together thoroughly, the part may look fine but integrally  it will be weak. Why take the chance. We are talking maybe $10-$15 difference. Fire control parts is not a place to go cheap. Do that on a hand guard or site or something. Craig
Link Posted: 1/28/2022 1:21:18 PM EDT
[#16]
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That would be easy, put them end to end. One is .014" higher and you can feel it, don't need to see it.
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The premise was simply resting on a table and differentiating by sight. Holding them or or arranged in a manner to tell is a different manner.
Link Posted: 1/28/2022 1:22:08 PM EDT
[#17]
Oops dupe
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