Hatsan QE moderator

[naptemp]

I had a Hatsan Invader for a while.
I managed to tune it down but it's still too loud with the original shroud.
It uses a shroud with a M27x1 thread like many of the newer Hatsan QE models.
It could really use a moderator attached to the shroud.

Subscriber thank you again for everything you have done, and do not do this unless you really want to.
I feel like I have already asked for too much.

If and when you are willing to design an LDC let me know and I can post the exact dimensions and photos.

[subscriber]

John,

I read your post by chance.  A PM would be more likely to reach me. 

If you post something like this, you should also add enough detail to be useful.   If I don't want to do it, I can pretend I did not see it

Are you talking about a Hatsan PCP?  What caliber and power level?

[naptemp]

John,

I read your post by chance.  A PM would be more likely to reach me. 

If you post something like this, you should also add enough detail to be useful.   If I don't want to do it, I can pretend I did not see it

Are you talking about a Hatsan PCP?  What caliber and power level?

My Hatsan QE PCP (Invader) is .22 caliber.
The Hatsan PCPs with the QE shroud also come in .177 and .25 calibers.

They have a shroud which have an internal M27x1 thread at the end.

I have attached some photos of the shroud endcap.

The moderator needs to have the same external M27x1 thread, 15-18mm long.
The endcap (34.2mm OD) is supporting a handguard so the moderator should be at least 35mm OD.

There is also the small spring guide, with an OD of 16.6mm.
The small unthreaded shoulder used for the o'ring can probably be ignored, and just have the thread there.

The last photo is a drawing of the endcap with the dimensions measured with a caliper.

The inner hole diameter can be reduced to whatever works for the caliber, this should also make this part stronger.

[naptemp]

More photos.

[Back_Roads]

 A member sent  out some test LDCs that fit inside the QE shroud and do a good job on my  .25 Bull Boss, I think they had plans to sell them, trying to remember who it was.

[subscriber]

John,

I trust the attached design might meet your needs, in one iteration.  One can only hope

[subscriber]

The LDC above would be strong enough to use without the benefit of a shroud taking the initial punch on firing.  The lightweight version of the LDC attached to this post, has thinner outer walls.  My suggestion is that you try the latter to save weight, as the first version is stronger than necessary.

Other than the outer wall thickness, all other details are the same between versions.

[Chief-10Beers]

Is there a Link to read more about these Moderators?   Thanks!

[subscriber]

Grant,

James might provide a description of the shroud insert he acquired.  Else, this is what I could find in a quick search:

https://www.gatewaytoairguns.org/GTA/index.php?topic=159749.20

https://www.gatewaytoairguns.org/GTA/index.php?topic=141954.0

https://www.gatewaytoairguns.org/GTA/index.php?topic=175135.msg155978001#msg155978001

https://www.ebay.com/itm/10-Stage-Vented-Baffle-for-Hatsan-Air-Rifles-Flash-Nova-Flashpup-etc/333276251950?var=542292293339

[Back_Roads]

 Here is the final product of what I tested. https://www.ebay.com/itm/10-Stage-Vented-Baffle-for-Hatsan-Air-Rifles-Flash-Nova-Flashpup-etc/333276251950?var=542292293339

[elguapo99]

I have the Geoffk insert in my Hatsan QE .22 shroud and all you can hear is the clunk of the hammer on the valve and the sound of the pellet hitting the target. It is running at 28 fpe.

[Back_Roads]

I have the Geoffk insert in my Hatsan QE .22 shroud and all you can hear is the clunk of the hammer on the valve and the sound of the pellet hitting the target. It is running at 28 fpe.

50 FPE .25 Bull Boss more of a "Phunk" sound with that power level. Slug impact louder.

[subscriber]

If I were looking, a good insert would appeal to me more than an add-on moderator.  Now, consider that John (the OP)  might like the idea that he can print his own moderator for $1, as opposed to buying the insert for $32.

[Chief-10Beers]

Thanks for the Replies!  I don't have a Hatsan, I am getting a new to Me rifle tomorrow and was looking for a Threaded Moderator. Using the Name GeoffK  I found a Combination Baffle Insert with Mod on the End.  Looking to keep things quiet. I don't know that I need a DFL $200 Mod to achieve that. But also a few $40 Cheapies add up. Wondering if it will indeed reduce Noise.    Thanks,
Grant.

[naptemp]

The LDC above would be strong enough to use without the benefit of a shroud taking the initial punch on firing.  The lightweight version of the LDC attached to this post, has thinner outer walls.  My suggestion is that you try the latter to save weight, as the first version is stronger than necessary.

Other than the outer wall thickness, all other details are the same between versions.

I printed the threaded part of the lightweight LDC.
After printing, the threaded part is 25mm OD instead of the 27mm OD for a M27x1 thread.
The thread seems to be wrong.

[Back_Roads]

Thanks for the Replies!  I don't have a Hatsan, I am getting a new to Me rifle tomorrow and was looking for a Threaded Moderator. Using the Name GeoffK  I found a Combination Baffle Insert with Mod on the End.  Looking to keep things quiet. I don't know that I need a DFL $200 Mod to achieve that. But also a few $40 Cheapies add up. Wondering if it will indeed reduce Noise.    Thanks,
Grant.

TBH I have many less expensive  many 3D, and some just as expensive, that are quieter than a stock  Donny FL.

[Chief-10Beers]

Good to know!  I guess I will just have to take My Chances and try one.

[subscriber]

I printed the threaded part of the lightweight LDC.
After printing, the threaded part is 25mm OD instead of the 27mm OD for a M27x1 thread.
The thread seems to be wrong.

I tried to apply more shrinkage compensation after making threads too tight on your previous project.  The attached Version 2 STL has no thread shrinkage compensation applied.  Lets see if it fits the female thread, rather than just measuring the OD.  I expect it to be tight.

The sketch used to define the V2 thread shows a radius of 13.5 mm (27 mm diameter) - image below.  The first version had the thread form shaved by 0.15 mm at both flanks.  That would reduce the effective diameter by less than 1 mm, so being two mm short on OD seems odd.

If you change your print settings, the thread diameter is likely to change...  If V2 is too tight, then print with the X and Y axis scaled to 99.5 %.

[naptemp]

Subscriber, I printed the threaded part of the last version at 100%.
The OD of the threaded part is around 25.5-25.8 mm.

I do not think that the thread is M27x1.

Can you check the thread size?

[subscriber]

John,

The first image below is confirmation that my CAD model is driving a 27 x 1 mm thread.

The OD of a thread is the least significant aspect of any thread.  So is the ID, because oversize drills are often used before tapping.  The correct way to measure a thread is with thread wires of the appropriate diameter.  That measures the effective diameter of the thread.

When it comes to FDM 3D printing a thread, there is no way that the sharp "tips" of the triangular thread-form at the theoretical OD can be reproduced.  The print resolution is not fine enough, and the filament is too large.  The molten filament tends to droop and distort the triangle, and reduce the OD further.

Commercial threads have a small flat at the OD.  As such, they always measure smaller than the nominal size.  There is hardly any strength in the very "tip" of the thread-form; it is hard to manufacture, and it is easily dinged.

You may be running a fresh roll of filament that has less water absorbed into it.  A different type of material, or different settings.  I do not mind trying to help you further, but only if you report how the thread feels when screwed into the Hatsan shroud.  If you persist with measuring OD and using that as sole criteria I can't do very much for you.  Yes, a 25 mm printed thread will fall into a 27 mm metal threaded tube.  Just as certain as a 27 mm OD print will not thread into a 27 mm threaded metal tube.

The best I can offer is version 3 of this LDC.  As you can see from the second image below, it has an oversize OD at 27.8 mm, but the thread width is relieve to reduce the probability of jamming.

The fact that your printed parts have gone from much too tight to screw in, to so loose that there is no overlap, has to provide a clue.

The fact that the thread OD is 0.2 mm small is not an indication of a fault.  Measure a commercial bolt with a nominal 27 mm diameter, and you will see something similar.

The fact that you see 26.5 to 26.8 mm in your printed part means your printer is struggling.  Or, the system cannot make such a sharp thread-form and you are seeing a sampling problem. Also know as aliasing.

Normally I chop the "tops" off threads I design, because the printer can't make them anyway.  I leave a 0.2 mm "flat" at the crest in CAD.  This makes the OD measure smaller, but it is of no consequence.  It is like insisting on using PI to 8 significant figures, when 4 is plenty for most tasks.  If that bugs you, the last two thread designs are left "sharp", but your slicer will ignore it; and what the slicer does not ignore, your printer will battle to produce.

This does not work like the fictitious TV shows, where the cops can take a low resolution license plate picture captured from a block away, then zoom in 20X, making resolution out of nothing until the image is clear.

The STL also has limited resolution.  Each aspect of the "image pipe" blurs detail further.  If you want the best resolution for printing that does not entail massive print files, get yourself a slicer that can use STEP files instead of STLs.

I can't perform magic, and I am running low on patience.  Eventually you must consider that something you changed deliberately, or inadvertently has had a massive effect on your thread fit.  It does no good for both of us to chase the fit.  I can CAD threads at nominal values, and you can choose the knobs available to you to achieve the fit you want.  Or I can try to help. 

Usually, unless a thread is to be chased with a tap or die, relieving the thread-form is required for a 3D printed thread to fit.  Today the threads are too small.  A day or two ago, they were too large.  You could go back and reprint the first file version of the Chaser LDC.  If the same file that was too tight 3 days ago is too loose today, the trouble is with your system; or the way you are using it.