Question Need to Start Sourcing Out Hammer O Rings forVM 68 - REPOST FROM MCB 2.0

[infamoussmiley]

Posted on 5-18-2016 by Giuseppe:

LOL! It definitely wasn't my intent to hijack this thread!

With all the difficulties in sourcing good hammer seals, I was interested in exploring options for eliminating them altogether. Unfortunately, it seems like Smiley has already tried most of these options, and none of them have worked!

I've been playing with the same EXC-68 since 1995, but it's only in the last few years, as parts have become harder to find, that I've really started tinkering with VMs, in an effort to keep mine running. The irony is, when I first started using the EXC, I was a broke post-college kid. Now that I can afford to buy whatever parts and accessories I want...there aren't any!

I'm happy to keep the seal hunt going here and let the other thread focus on alternatives. There's way too much good info in this thread to let it die!

[infamoussmiley]

Posted on 5-18-2016 by Giuseppe:


Quote:

Originally Posted by infamoussmiley We are currently experimenting with 3D printing in urethane.

I'm excited to hear more about this! My brother (who sent me the 3D design above) is having difficulty locating a printing substance that's not too stiff...

And, Smiley, thanks for the reminder about the rounded edges. I've passed that on to him.

[infamoussmiley]

Posted on 5-19-2016 by Daliz:


Dumb question, and I know nothing about VM68's, but have you looked at other standard than the AS568 o-rings, for example metric sizes?

Here's some size charts:
FFKM O-Ring | O-Ring | Viton O-Ring | Hydraulic Seal | Rubber Grommet | Gmors - Match You Always

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[infamoussmiley]

Posted on 5-19-2016 by Infamoussmiley:


Quote:

Originally Posted by Daliz Dumb question, and I know nothing about VM68's, but have you looked at other standard than the AS568 o-rings, for example metric sizes? Here's some size charts: FFKM O-Ring | O-Ring | Viton O-Ring | Hydraulic Seal | Rubber Grommet | Gmors - Match You Always

Thank you for the link. Those are actually great o rings.

As for the Hammer ring for the VM, it's not really an O ring. It's more of a flat washer with round outer edges.

Smiley

[infamoussmiley]

Posted on 10-23-2016 by BadAcid:


I'm sure this has already been tried and I will sound stupid for asking, but has anyone tried replacing it with a similar oring tight enough to not blow off and then using a higher viscosity lubricant like shocker lube or Dow 33

*** Note I have never fired a vm68 or tried to repair one ***

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[infamoussmiley]

Posted on 10-23-2016 by infamoussmiley:


Quote:

Originally Posted by BadAcid I'm sure this has already been tried and I will sound stupid for asking, but has anyone tried replacing it with a similar oring tight enough to not blow off and then using a higher viscosity lubricant like shocker lube or Dow 33 *** Note I have never fired a vm68 or tried to repair one ***

yeah... it doesn't work.


We are working on a solution, but it's not going to be cheap.

Smiley

[infamoussmiley]

Posted on 10-23-2016 by TomsGunShow:


Here's a document i found in the Harvard dept of physics online library. Its called the oring handbook. Not sure if this will be of any use but i thought it wouldn't hurt to show you.

https://www.google.ca/url?sa=t&sourc...TdedkUtiDm4BUg

Sent from my LG-D852 using Tapatalk

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[infamoussmiley]

Posted on 10-24-2016 by Infamoussmiley:


Quote:

Originally Posted by TomsGunShow Here's a document i found in the Harvard dept of physics online library. Its called the oring handbook. Not sure if this will be of any use but i thought it wouldn't hurt to show you. https://www.google.ca/url?sa=t&sourc...TdedkUtiDm4BUg Sent from my LG-D852 using Tapatalk

Thank you

I printed it out and put a copy in the one volume of the shop bible. thank you

Smiley

[infamoussmiley]

Posted on 11-1-2016 by infamoussmiley:


Might have found a place that can make the Hammer rings. Waiting for a quote. Crossing fingers.


Smiley

[infamoussmiley]

Posted on 1-31-2017 by Giuseppe:


Has anybody been able to make progress on the magic rings?

[infamoussmiley]

Posted on 2-10-2017 by infamoussmiley:




Quote:

Originally Posted by Giuseppe Has anybody been able to make progress on the magic rings?

Yes. Testing two sets of prototypes. Technically three sets. The third was a bust. We tried 3D printing them. They did not hold up after 20 cycles.


The two sets we have are installed in 6 VM-68s each that are in varying states of "usedness". Really hoping that the injection molded ones work out the best.

Will keep you all posted.


Smiley

[infamoussmiley]

Posted on 2-10-2017 by Tracker:


what material did you try the 3d printing with?

also playing a but of catchup on the suggestions, have you tried stacking a standard o-ring on top of an x-ring (quad 0ring) ala ule trigger shutoff on a mag, or would that not get the o-ring out far enough??

im talking about an x-ring in first, then a properly sized o-ring in second.. or does it need to be a smooth surface to push the hammer back

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Last edited by Tracker; 02-10-2017 at 07:03 PM.

[infamoussmiley]

Posted on 2-10-17 by infamoussmiley:



Quote:

Originally Posted by Tracker what material did you try the 3d printing with?

urethane. Tried 70 and 90 durometer.

Smiley

[infamoussmiley]

Posted on 2-10-2017 by Tracker:


i feel like there are more options for filament types, when you say urethane, im going to assume TPU, right? TPC perhaps? or ninjaflex TPE.. shame you cant but a few meters of sample materials for cheap to text the different types of materials

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[infamoussmiley]

Posted on 2-11-2017 by infamoussmiley:

I wasn't the one who did the 3d printing. I was just told they were done from a urethane stock. Either way, the 90 durometer felt off. And the round outer edges weren't uniform. They have to be to work right.

Can you tell me more about the different options for Urethane? Maybe we used the wrong type?

Smiley