Budget tuner

[katokoch]

With input from some previous threads on this and another forum, I finally got down to getting my design machined and finished. Well, it's not completely finished or entirely original, but close enough.

The final product remains close to this initial design

but with a couple changes.

Here's how it finished up.

What you see there is a .920" cylinder barrel, a 4" long peice of 1 1/4" diameter fine threaded steel, a fine threaded 1 1/4" zinc-plated nut, four 1 1/4" I.D. steel washers, and a couple hose clamps. You may notice that the nut is one of the stupid "locking nut" types with a plastic insert, but to get it to easily move across the length of the tuner I simply ground out the plastic. to free up the ends of the threads.

Pretty simple. I decided that taking a couple 1 1/4" nuts and cutting them to different lengths,weights) would be a severe pain, so I decided on another way to adjust the weight. Washers. I plan on taking the single nut, weighing it to determine the density, and cutting it in two peices to have two peices that weight the same. If the situation arises where I need finer adjustment than one of the big washers, I can easily trim one down, or add stick-on lead weights to another. However, this won't happen for awhile because I have yet to finish a stock for this rifle and I am just having the bedding block machined now, so I can't safely determine whether or not the rifle will make 10.5 or 13.5 lbs. Obviously, if the rifle will be in the 13.5-lb. class,IR 50/50), I will have more weight to play with on the tuner.

Now, as far as attatching the tuner to the barrel, 1" of the rod is bored out to .925" so it is a tight slip fit over the barrel. I made two cuts in the .925" end of the tuner, one across and one down so I can slip the tuner over the muzzle and use a simple hose clamp to tighten it up. Believe me, when I get the hose clamp tight, the tuner isn't going anywhere. I have a second if one ends up not being enough. The rest of the tuner is bored out 3/4".

I may end up just using the large nut to adjust the tuner, as it has over 3" of room to slide around, like this.

With maximum weight on the tuner,which is more than I see listed for any add-on weights for tuners), here it is.

I highly doubt I'll ever need this much weight to stop the muzzle, but I will be prepared. I don't have anything precisely weighed, but I do know the barrel is .920" cylinder, 20" long and fluted, so it's not the heaviest by any means.

The best part,for me at least), is that everything cost me $42 total. $30 from the machine shop and $12 from a Fastenal down the road for the nut, washers, and clamps. I had to spend some of my time and elbow grease on the thing as far as cutting and fitting, but I'll ignore that.

I've found a couple indoor ranges in my area so I've got some work to do.

 

[ronsroom1]

American ingenuity at work.

 

[graybeard]

katokoch
I have made and modified many tuners and yours will work, but I do not see how you plan to hold the washers in place to the threaded part. The nut will work on one side, but what about the other side? loose washers will cause you many problems and will not work.The nut needs something to be tightened against to stay in place.
Something to think about maybe.
Jim

 

[katokoch]

Yep... that photo isn't exactly correct as to how I may be using it. I'll eventually be splitting the nut in half and using it to tighten against the washers. As to keeping the nut locked in place, while testing I figure I can simply use electrical tape to lock it down and in the meantime figure out some simple mechanical means of holding it in place once I find a sweet spot.

 

[RichinKansas]

Ingenious! Only problem I see is no index. What I mean is a very small movement can have a big effect. You need to be able to turn the nut 1/24th of a revolution per increment or so till you find your sweet spot. Otherwise it will be no better than the original tuners that were no more than collars moved on the end of the barrel. If you do find a very good spot and you move the weight a tad more to see if it will get better, and it doesn't, you need some way of getting it back to the previous spot exactly.
You might be able to attach a nut near the muzzle with a scribed mark and then have another nut behind the washers next to the scribed nut with 24 increments scribed around it. They don't need to be numbered if you count.
I use two different tuners, one with 40 tpi and one with 24 tpi. One has 24 scribed marks and the other 25. Even one increment can make a serious difference and its very important to be able to return to a particular position precisely..

 

[katokoch]

I remember a couple years ago seeing a fella who made a jig to engine-turn Turk Mauser bolts and he used the six flat faces on a nut to do the indexing. I think if I can accurately measure how much one-sixth turn of the nut moves it,which I absolutely could), I would have an accurate indexing system. Marking length/position along the tuner body would be another beast though.

The tuner body and nut are fine threaded and I could accurately measure 1/12 revolution from the nut, so I do think this is a system that can be finely tuned. My marking system is what will make the difference.

 

[RichinKansas]

Your thread doesn't look that fine. How many tpi? I think you will need 24 or more. And 6 increments per revolution I think will take you right by the sweet spot unless your lucky. Rich

 

[katokoch]

Your thread doesn't look that fine. How many tpi? I think you will need 24 or more. And 6 increments per revolution I think will take you right by the sweet spot unless your lucky. Rich

Well, without doing any measuring, I've got at least 12 "simple" increments on the nut. I can use both the points and middle of the flats, so that's six plus six.