Prefect fit
Great adapter for my Thompson A1
The 1.375x24 Cutts Compensator Adapter was designed by the Griffin Armament engineering team to allow for the mounting of Griffin's Bushwhacker 46 silencer to an unmodified 1928a1 Thompson submachine gun via the Cutts Compensator.
Specs:
THIS ADAPTER REQUIRES A PRECISE FITMENT FROM A COMPETENT PROFESSIONAL GUNSMITH.
Recommended installation steps are as follows:
The gunsmith will need a milling machine and a lathe, and some skill to fit this properly. The Thompson front sight length varies, and may either require shortening of the front of the front sight, or the milling of the forward face of the clearance slot to allow the part to fit the front sight with correct fit tolerance of +.003-.000. The ID of the mount has two rings that need to be ID turned to a .0003-.0005" slip fit+.0005-.0000 tolerance correspondent to the mated Cutts compensator. The part will need to be tapped into indicated true, prior to making these cuts to ensure alignment is maintained. The recommended insert for ID turning would be a .016" corner radius carbide insert for machining aluminum (up sharp/ polished) at ~200 SFM, with .0025" / Rev feed. This will prevent getting into a situation where .0005" needs to be removed with a more dull, coated insert incapable of taking a very slight cut. ID ball or flapwheel honing once within .0003" of desired fit, may be another useful tool to derive near perfect fit. Some wartime Cutts comps tapered smaller toward the sight from the muzzle, and this condition may require the compensator itself to be indicated true, and a very light .003 or .004 diameter cut taken again with a carbide insert for aluminum. The reason for this is that it will be impossible to mount the adapter with low runout if the rear band has to be large enough to pass over a surface .0025" larger than where it will sit in the mounted configuration. In summary this part is somewhat challenging to fit, but not as challenging as it was to design and manufacture, and it exists here so that we are not the only people with access to the Cutts Compensator Mount, and this uniquely enjoyable capability which to some might be the fulfillment of a dream to shoot a suppressed 1928a1 Thompson.
Liability for proper fitment rests on the customer selected professional gunsmith. This product is not covered under our warranty policy once modified for fitment and cannot be returned or exchanged.
Great adapter for my Thompson A1
Had to machine the Cutts comp and sight but it works on my modern thompson clone. When installed I heard a bald eagle screech and John Thompson and Winston Churchill shed a single tear as they marveled at the beauty griffin armament had birthed to life.
