SumToy mount torque value?

[Elmerfudd]

About to screw a new SumToy mount to an M2. What are the torque values that William recommends? Id assume he is up to his butt in metal shavings this time of year and I dont want to bother him with a call.

[rdjustham]

I snugged mine up like i would on a rifle and used blue loc tite, didnt use a torque wrench and havent had any problems.  Shoot william a message on FB he will get back to you.

[dzsmith]

I will tell you this....a standard scope base of any kind for a rifle is usually 25 in/lbs...im sure you know this. Depending on what gun you use this on and what screw you use can change this when it comes to mounting it on a shotgun with shallow recievers and super short screws. My marlin 336 base on my 870 was tightened to 25 in/lbs with blue Loctite with zero issues, however a friend of mine used the screws from his picatinny on a stevens 410 and the screw broke before he even made it to 20lbs using a wheeler fat wrench. After calling stevens they did in fact have a much lower torque suggestion for that particular set up. the screws that typically come with burris mounting systems such as the 336 mount seem to be beefy enough to handle a standard optic base torque of 25 in/lbs but that doesn't mean they all can. so keep that in mind. by the way this guy called William for that torque value before mounting the sumtoy mount on his stevens and William didn't have an answer for that. so he called stevens/savage and waited so long on the phone he decided to just go to 25 in/lbs and broke it. he has also reordered those screw from savage twice in the last 3 weeks and never received them....its getting mighty close to turkey season to break an impossible to find screw , and they are IMPOSSIBLE to find for that stevens.

[SumToy]

sung them.   Every one want to talk 25 inch pounds because of a rifle.  Rifles are steel most shotguns are aluminum.  I have seen gun strip and screw broke because of this. .   

[dzsmith]

sung them.   Every one want to talk 25 inch pounds because of a rifle.  Rifles are steel most shotguns are aluminum.  I have seen gun strip and screw broke because of this. .   

I agree, my 870 has a steel receiver, and I had no issues with 25.....but that's definetly not the case with other guns. Gots to be careful...

[Biggin]

I'm fixing to mount a sumtoy base and FF3 on SBE 2 and I would love to know what in/lbs to use.

[Elmerfudd]

Mount is going on a new M2 20 gauge. I had my local smithy drill and tap the receiver which I'm sure is aluminum but wow is that some hard aluminum. He said it was nearly as tough as steel. All that said - yes 25 in/lbs is way too much for aluminum mounts going to aluminum receivers. William says snug it up.

Ok, I'm going to snug it up with my fat wrench and will advise what torque reading was "snug"

I will be shocked if it's any more than maybe 15 in/lbs. my main concern is that I don't want to bend/torque the center of the sumtoy mount by over torquing the two screws

[dzsmith]

that's what the recommend torque for the savage stevens 410 is on the picatinny rail. 15lbs. you should be good. I know one good rule of thumb on a compound bow is when tightening a screw "when the a thin allen key starts to flex a little, stop"

[Elmerfudd]

OK, I got the Sumtoy mount installed and the Holosun bolted to it. 15 in lbs felt right without any undue stress. If you dont have a torque wrench, 15 in/lbs equates to snug and an 1/8th turn according to my machinist pal. He thinks for steel screw into aluminum receiver 10 in/lbs would be adequate. Too late  I was finished before I talked to him.

The mount did not flex at all, and it feels rock solid without stressing anything. Used Blue loctite. 

To be honest, the way the mount straddles the receiver so closely, I cant see how it would move anyway. Ive heard that SumToy uses glue as well when mounting these? Im not sure why that would be necessary.

I did encounter 2 minor issues with the install - Screws from Sumtoy that came with mount were just a little too long and were interfering with my action. I shortened them a bit and problem solved. Second issue - Center screw that I needed to install in slotted section was sitting up just a bit proud of the base when installed correctly - The sight would wobble just a bit instead of sitting flat on the machined base. Pulled the screw, flattened the top a bit with a fine file, reinstalled, problem solved.

Looks great. Easy Peasy, off to the range. Cant wait to zero and try the new Sumtoy choke as well.

[Meleagris gallopavo]

I bent my Sumtoy base mounting it to my 835 and had to get a new one.  When the base came in I immediately placed the Vortex Venom on it and it went right on.  When I mounted it on the gun with a screwdriver, I evidently got a little over-zealous and tightened it so much it flexed/bent and the sight wouldn't fit on it anymore.  Took it off and messed with them and couldn't get them to match up.  I messaged them about it and they said they have heard of that before and they sent me another one free of charge.  They are awesome!  What kind of little torque wrench do you use for these small applications?

[Jroddc]

I bent my Sumtoy base mounting it to my 835 and had to get a new one.  When the base came in I immediately placed the Vortex Venom on it and it went right on.  When I mounted it on the gun with a screwdriver, I evidently got a little over-zealous and tightened it so much it flexed/bent and the sight wouldn't fit on it anymore.  Took it off and messed with them and couldn't get them to match up.  I messaged them about it and they said they have heard of that before and they sent me another one free of charge.  They are awesome!  What kind of little torque wrench do you use for these small applications?

A torque screwdriver

[Elmerfudd]

I use a Wheeler Engineering Fat Wrench - it's a torque screw driver. Can buy at Midway, Cabelas etc.

[Ridge Rooster]

I have about 6 Sumtoy bases and helped install another 3 or 4. I use blue Loc-Tite and 15 inch lbs of torque. Burris manual recommend 12 inch lbs for there sight screws and I use 15 on them also with blue Loc-Tite. Have never had one come loose. The reason I use 15 instead of 12 is 15 is easier to see on my torque wrench. I have noticed that the bases flex slightly on the last 3 I did. Sight goes on but really tight and prior to installation it fits easy.

Ridge Rooster

[Jha22msu]

I realize this is An old thread but 2 questions why do so many people use blue loctite on threads for scope or gun mounts?  It is for 1/4 inch and larger. You should be using 222 purple which is for 1/4 and smaller.  Also on torque values bolts will have two torque values dry and lubricated threads so if it was 12 in-lbs dry it will be less than that once you added loctite bc that goes to the lubricated specs

[SumToy]

I realize this is An old thread but 2 questions why do so many people use blue loctite on threads for scope or gun mounts?  It is for 1/4 inch and larger. You should be using 222 purple which is for 1/4 and smaller.  Also on torque values bolts will have two torque values dry and lubricated threads so if it was 12 in-lbs dry it will be less than that once you added loctite bc that goes to the lubricated specs

VERY true.  The lube on the bolts changes everything.  That is why the go by bolt stretch in a race engine not torque