Umarex Notos CRK Review

[Firewalker]

There is something horribly wrong!

My trap has become unbelievably loud after I attached that insert! Its all I can hear, snap... BANG!

Didn't even know the pellet trap even made noise until I put that sucker in that housing! 

[miksatx]

Printed up a short snout yesterday the pin holes came out really good.

[Rat Sniper (AKA: PaulT58)]

Good to hear, how is the pin alignment when inserted into the housing?  I ordered some PETG, it should arrive tomorrow, so I'm hoping to do a print this weekend.

[miksatx]

Good to hear, how is the pin alignment when inserted into the housing?  I ordered some PETG, it should arrive tomorrow, so I'm hoping to do a print this weekend.

lol good question I can't answer. don't own a Notos. You can see through the holes good enough to line up for drilling.

[Rat Sniper (AKA: PaulT58)]

Good to hear, how is the pin alignment when inserted into the housing?  I ordered some PETG, it should arrive tomorrow, so I'm hoping to do a print this weekend.

lol good question I can't answer. don't own a Notos. You can see through the holes good enough to line up for drilling.

Well, do you plan on getting a Notos?  If not, was that printed for someone specific to test fit?  If not, I'd be happy yo assist!

[miksatx]

Good to hear, how is the pin alignment when inserted into the housing?  I ordered some PETG, it should arrive tomorrow, so I'm hoping to do a print this weekend.

lol good question I can't answer. don't own a Notos. You can see through the holes good enough to line up for drilling.

Well, do you plan on getting a Notos?  If not, was that printed for someone specific to test fit?  If not, I'd be happy yo assist!

PM me and i will give you the details.

[subscriber]

Thanks for doing that, Mike

[Firewalker]

Thanks for doing that, Mike

One last question before you go walkabout:

What about making a version that is open until it hits the step in the housing?

The pins still hold it, the large space right off the barrel end would allow for greater expansion.

Thoughts....

[subscriber]

Dave,

What you asked for above, is what I have attempted to provide:

The lengths of the latest inserts are shorter than what you have installed.  They are short, like the original insert on the small end (unless I screwed up).  So, there is already a large primary expansion space ahead of the first cone.

The attached image shows the first replacement insert I designed for you, on top.  You trimmed its end cone to get it to fit, so for the stock casing, I moved the cone shoulders forward a bit on these latest inserts.  They locate on the shoulder at the front of the casing, and by means of the pins, but lack the conical alignment at the muzzle end due to an intentional gap there.  Hence, me bumping up the insert OD to take out slop between insert OD and casing ID.

No need for the o-ring with these insert either.

Otherwise, if you could be more specific about what you want I should be able to do it.

[subscriber]

In case I got the pin hole locations so wrong that someone might prefer to drill their own, the STL files attached to this reply are for the above long and short snout inserts, but without pin holes:

[Firewalker]

Dave,

The lengths of the latest inserts are shorter than what you have installed.  They are short, like the original insert on the small end (unless I screwed up).  So, there is already a large primary expansion space ahead of the first cone.

The attached image shows the first replacement insert I designed for you, on top.  You trimmed its end cone to get it to fit, so for the stock casing, I moved the cone shoulders forward a bit on these latest inserts.  They locate on the shoulder at the front of the casing, and by means of the pins, but lack the conical alignment at the muzzle end due to an intentional gap there.  Hence, me bumping up the insert OD to take out slop between insert OD and casing ID.

No need for the o-ring with these insert either.

Otherwise, if you could be more specific about what you want I should be able to do it.

Ahhhh! You already located off the shoulder! Nevermind 

[TorqueMaster]

The images below show my best effort at extended inserts (similar to what Dave tested) designed to fit the unmodified Notos "can". 

I scaled the retention pin positions from the images in this thread, and applied a human trait:  When there is no clear reason to choose fractional dimensions, most designers default to full units.  So, the pin to pin spacing seems to land 8 mm away from the centerline, and thus 16 mm center to center, placed in the 32 mm OD casing.  I did something similar for the pin placement from the casing shoulder.

Instead of Subscriber making an educated guess on hole locations, could Firewalker put the pins halfway into the stock cap holes, and measure their CTC distance between the heads?  And also measure/estimate the distance from the centerline of pin holes in the cap (when installed) to the front edge of the shroud? 

Similarly, measured depths and angles of what is inside the shroud (or what's left) would help as well.

[Firewalker]

The images below show my best effort at extended inserts (similar to what Dave tested) designed to fit the unmodified Notos "can". 

I scaled the retention pin positions from the images in this thread, and applied a human trait:  When there is no clear reason to choose fractional dimensions, most designers default to full units.  So, the pin to pin spacing seems to land 8 mm away from the centerline, and thus 16 mm center to center, placed in the 32 mm OD casing.  I did something similar for the pin placement from the casing shoulder.

Instead of Subscriber making an educated guess on hole locations, could Firewalker put the pins halfway into the stock cap holes, and measure their CTC distance between the heads?  And also measure/estimate the distance from the centerline of pin holes in the cap (when installed) to the front edge of the shroud? 

Similarly, measured depths and angles of what is inside the shroud (or what's left) would help as well.

I'm sure HE could but anybody could. 

I have no shoulders to measure any longer, I am 1" all the way to the barrel.

[TorqueMaster]

In case I got the pin hole locations so wrong that someone might prefer to drill their own, the STL files attached to this reply are for the above long and short snout inserts, but without pin holes:

Excellent!  I doubt you are off by much, but this allows for correction if needed, thanks!

[TorqueMaster]

The images below show my best effort at extended inserts (similar to what Dave tested) designed to fit the unmodified Notos "can". 

I scaled the retention pin positions from the images in this thread, and applied a human trait:  When there is no clear reason to choose fractional dimensions, most designers default to full units.  So, the pin to pin spacing seems to land 8 mm away from the centerline, and thus 16 mm center to center, placed in the 32 mm OD casing.  I did something similar for the pin placement from the casing shoulder.

Instead of Subscriber making an educated guess on hole locations, could Firewalker put the pins halfway into the stock cap holes, and measure their CTC distance between the heads?  And also measure/estimate the distance from the centerline of pin holes in the cap (when installed) to the front edge of the shroud? 

Similarly, measured depths and angles of what is inside the shroud (or what's left) would help as well.

I'm sure HE could but anybody could. 

I have no shoulders to measure any longer, I am 1" all the way to the barrel.

I guess I misunderstood, I figured the cap was still intact and measurable.  I'll look at your pix again.

[subscriber]

Dave,

Bob means the front of the casing, at the large shoulder on the insert.    Not the one inside the casing that you removed.

Details required:
1. Pin diameter where unknurled
2. Distance between pins measured over their OD (to subtract OD and find center to center). As Bob suggested; tap the pins out just far enough to get a caliper beak on them.
3. Distance of pin center or OD to casing front face.  Be specific, please.

Thanks

[subscriber]

I have a confession to make; the pin hole spacing in the designs above is not what I calculated.  The hole center to center in the above parts are at 18 mm.   My most recent calculation from the images was that they were 16 mm apart.

I know it seems silly to upload another file version with the holes at 16 mm spacing, but I have no idea if, or when someone will provide me with actual measured data. So, the best I can do is to meet my own intent.  Then you guys can determine which is closer.  Either should let you sight through the holes in the casing, to chase the holes so the pins will fit.

Hence the attached versions below with the pin holes spaced at 16 mm.  Yes, the pin holes just break through into the air space at two points.  Should not make any difference, as that is what Dave would have with his hand drilled pin holes.  Unless he or someone else provides measurements to the contrary...

[subscriber]

Paul (Rat Sniper) kindly took careful measurements off his Notos and I have incorporated those into  my CAD models.  Note the RS pin spacing designation in the attached STL files, below.

My 16 mm center to center pin spacing was slightly less than 0.5 mm off.  Paul's center to center distance no longer has the pins break into the air space inside.

[Rat Sniper (AKA: PaulT58)]

I have a confession to make also, while measuring the parts for Peter, I completely overlooked a significant part of this puzzle, the end cap!  It's designed with two tabs that fit into twc cutouts in the outer housing, so the round design Peter has been working on will not be a direct, drop-in fit without modification!  I have sent Peter the measuments relavant to the tabs...

[subscriber]

Paul, the problem you are seeing may be an illusion:

Based on the images posted by David, including the one below, that ring pops out easily.  My designs all assume the ring is popped out, and that the insert fits into the casing directly without either the ring or the encap with its air stripper. 

See part "B" in the image below.  That is a separate part.  Dave did bore away plastic at the shoulder deeper into the casing, that the conical end of the stock insert bears against.  You do not have to do that.

The central bore in part "B" is smaller than the casing ID deeper in.  So I am not going to attempt a design that fits through that smaller hole.  If you removed your stock red insert, you would have to remove that ring part anyway.  Try it...

It is up to you to decide what you will or won't do, but I think you are mistaken about the degree of to which removing that part constitutes a permanent modification.    I suggest that you ask David (Firewalker) about this directly, as he has taken the part out.