Lightening hammer spring in an early Marlin 94?

[Muddy Creek Sam, SASS# 78004]

Howdy all,

 

Got the ejector fitted and working smooth as silk, now th only hard part of levering the rifle is hitting the hammer and cocking it. How do I lighten the hammer spring? Cautions?

 

Thanks,

 

Sam

[Larsen E. Pettifogger, SASS #32933]

First see if you can get a replacement spring. Then the only real way to lighten a leaf spring is to judiciously grind it thinner or narrow it and then polish it good to remove any grinding marks. Loosening the retention screw or trying to bend it really isn't the way to do the job.

[Muddy Creek Sam, SASS# 78004]

First see if you can get a replacement spring. Then the only real way to lighten a leaf spring is to judiciously grind it thinner or narrow it and then polish it good to remove any grinding marks. Loosening the retention screw or trying to bend it really isn't the way to do the job.

 

Larsen,

 

Thanks again for sharing you knowledge.

 

Sam

[Driftwood Johnson, SASS #38283]

Howdy

 

I too have a very old Marlin with a flat leaf type spring. The only way to lighten the spring is to grind it.

 

A few of cautions; if you get it too hot, the steel will loose its temper and you will have ruined the spring. If you leave any horizontal grinding marks on it you will have created stress risers, and the spring can snap in half on them. If you leave any sharp edges or corners, the spring can also snap in half on them. Lastly, if you remove too much metal, the spring will become too weak, and it will be useless.

 

OK, that's it for cautions. You might want to look into calling up Numrich Arms and seeing if they have any extra springs, just in case.

 

When I grind down a spring, I use my dreaded Dremel tool. I chuck the largest diameter grinding wheel in it that I can find. I do not hold the spring in a vice, I hold it in my hand. The spring will get too hot to hold before you ruin the temper. After each pass of my grinding tool, I dip the spring in water to keep it cool. Only work the length of the spring, do not work across the spring, that way you will not create horizontal grinding marks (stress risers). I usually 'butterfly' the spring a little bit. This means to narrow the spring slightly in width, while leaving both ends the original length. If you choose to butterfly the spring, keep the angles of the butterfly very shallow, no sharp angles. Before you bend the spring, go over it everywhere with the finest sandpaper you have and completely remove any burrs, nicks, dings, gouges, sharp corners, anything that may create a stress riser.

 

You will have to put the spring back in the gun to figure out if you have taken off enough metal. Pop a few caps with it. Then take it out and grind a little bit more. This can be a long process. Remember to remove all stress risers everytime before you test it.

 

My old '94 did not have a strain screw for the main spring. I had Happy Trails drill and tap it for one, that way I could fine tune the spring and tweak it just a bit so that I could keep enough pressure on the hammer to reliably fire all primers, but still keep the cocking effort to a minimum.

 

Good Luck

[Yellowhouse Sam # 25171]

Wisners carries a lot of old Marlin parts.

[Muddy Creek Sam, SASS# 78004]

DJ,

 

Great tips. Numrich shows the Flat Spring in stock and a wire type Main spring.

 

Thank you.

 

Sam

[Three Foot Johnson]

I broke the mainspring on my vintage .38-40 1894 a couple years ago, and didn't have time to wait on a replacement. I had a spare 1873/1866 spring that worked just fine... after shortening it a bit and slightly enlarging he screw hole. I have never "ground" a flat spring, but instead use a draw file to thin and/or narrow it to my liking.