Spring gun tuning: Part 9 – Cleaning and deburring

Spring gun tuning: Part 1
Spring gun tuning: Part 2 – Building a mainspring compressor
Spring gun tuning: Part 3 – Mainspring compressor continued
Spring gun tuning: Part 4 – Let’s disassemble a gun!
Spring gun tuning: Part 5 – Powerplant disassembly
Spring gun tuning: Part 6 – Disassembly completed
Spring gun tuning: Part 7 – Disassembly of other spring guns
Spring gun tuning: Part 8 – Disassembly of other spring guns, continued

by B.B. Pelletier

We’re ready to tune the Beeman R1. This will be a low-power tune using an aftermarket coiled steel mainspring and the factory piston and seal. The R1 factory piston is pretty good, and the piston seal is very good. I am looking for a smooth-shooting gun that cocks easily.

First, we deburr
There are several parts of the powerplant that have extremely sharp edges. Sometimes, these edges get mashed or rolled into the path of moving parts, so it’s a good tip to remove the burrs before the tuneup. Be very careful when handling all parts, because they can cut as quick as an exposed razor.


Use a file to remove any burrs found on powerplant parts. The cocking slot shown here is a likely place for them.
I use Swedish files for this job. They make short work of the burrs. If you have never filed or applied stones to steel surfaces before, you’ll want to go very slow. This isn’t like sanding wood. Sometimes, all it takes is a single light stroke to accomplish your goal.

Parts that usually have burrs

1. The cocking slot in the spring tube.

2. The spring guide, where the piston passes through.

3. The cocking slot in the piston.

4. Any articulated linkage in the cocking link.

5. Any link between the cocking link and the piston.

Those are the usual places that have burrs on a new gun. You can find the others by running your finger LIGHTLY around all the parts that move. Be careful, because you can easily get a metal splinter this way!

Now we clean
We clean every surface of the powerplant and parts, both inside and out. Inside is the most important. The two hardest places to reach are also two of the most important places that have to be very clean – inside the piston and inside the mainspring tube. To reach into these two deep places, I have a screwdriver with an 18″ blade that I wrap with paper toweling. It takes only a small piece of towel at one time. I use rubber bands to hold it on the blade, and I use denatured alcohol to clean the gun parts. It dissolves all greases and dries completely. Mineral spirits leave an oily surface that has to be dried before you can continue. WD-40 leaves a film that turns to yellow varnish. Alcohol is the best solvent I have ever found to clean a sprung gun.


Wrap a piece of paper towel around something long, such as a screwdriver blade or even a dowel, and secure it with a rubber band. Dipped in denatured alcohol, it dissolves grease quickly.
The smaller parts are cleaned with cotton swabs dipped in denatured alcohol. I always have a couple dozen clean ones when doing this job. You also need rags for general wipes, and I like to work on a terrycloth towel. It not only protects the surface of the table, it also prevents tiny parts from rolling far.

The next step is lubrication.

14 thoughts on “Spring gun tuning: Part 9 – Cleaning and deburring


  1. Off topic —

    Do you think the Eun Jin 28 gr .22 cal are too much pellet for an RWS 52?

    I noted your comments in a previous column (/blog/2006/02/best-pellets-for-the-diana-rws-52-how-to-pick-pellets-for-any-springer/,
    where you opined that the short stroke of the side-lever action tends to favor lighter pellets.

    I was considering picking up some JSBs and kodiaks but if the 52 can handle it, I would like a big ol’ slug for certain larger game.

    As always, your opinion is much appreciated.


  2. Eun Jins,

    This is only my OPINION, because I’ve never tested Eun Jins in a 48/52.

    You are right that I think they are too heavy to give great accuracy, but I don’t think it would hurt your gun to try them.

    My bet is on the JSBs, followed by the Kodiaks, but I have seen Kodiaks do better in big spring guns like these.

    Please tell us how all this goes.

    B.B.


  3. Hi B.B.,

    I googled “Swedish files” and variations. All I found is “Dr. Scholl’s Pedicure Essentials” and articles about computer file swapping.

    I searched tool seller’s web sites but only found Swedish wood carving knives.

    So, Uncle! What do you mean by “Swedish files?”

    Cheers,
    GH



  4. Bingo! Thanks, B.B.

    I googled “Swiss files” and came up with some great tool seller bookmarks, for my tool fetish! Fortunately, I already have medium and small sized sets of files. I’m surprised I don’t recall ever hearing precision files being called that.

    Cheers,
    GH


  5. Not sure if you are going to see this but what the hey.Along with the previous post (from 2006!!!) I am looking into buying a few good quality files.I was wondering if you knew what cut the ones you use/prefer have.I think the range is from 00-6.Seems Grobet files are the best (but $$$).




  6. Hi BB,

    I know this is an old post, but I want this question with it. I own a HW77k.
    I have read other write ups on tuning springers. And they buff out the machining marks left on the metal from manufacturing. After the deburring you showed. Like in this write up.
    https://gunroom.com.au/air-rifle-tuning-a-hw77-at-home-part-1/
    He polishes the inner end of the back block, the outside of the cylinder, the piston, the spring ends & the end of the spring guide. I can see how polishing the cylinder & the piston will lower friction.

    What are your thoughts on this?

    Thank You,
    Ned


    • Ned,

      Welcome to the blog.

      I think he does a lot more work that necessary. He’s being thorough but wasting some time, in my opinion.

      Deburr and smooth the parts that tough and leave the rest alone. They are all that matter.

      B.B.


  7. Thanks for the quick response BB,

    Just looking at the compression tube through the loading port of my week old Weihrauch HW77k. I can see no need to polish one in a well kept gun. That said I noticed 2 small scratches on the compression tube last night while wiping the gun down after shooting. Which makes me think there is some grit from the factory in there.
    I ordered a piston seal & lube kit from James Maccari yesterday. Thanks for the link. I plan on building a spring compressor. And opening up my HW77 cleaning it out, checking for burrs & rough spots. Filing & polishing as necessary. Also replacing the oem piston seal & properly lubing the gun. On a new gun with no spring twang. Should I use Tar lube on the spring?
    The scratches on the compression tube & the fact that it is diesels with every 16gr pellet, every 4th 17.1 gr. Makes me think a little too much grease got in front of the piston seal on assembly, at the factory.

    Thanks,
    Ned


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