Straightening win. 86 mag. tube.
I have two mag tubes slightly bent in fire. Would like to have them straightened. Any Ideas? Does any body offer this service? They are both special longer than standard tubes and I'd like to salvage them if possible. I tried supporting one between V-blocks and used a clamp from under bench to bring into alignment but it springs back to it's original bent position. I'm leery of heating it because of the seam in the old tubes, I think it may open up the seam to heat and try to bend. Just wondering if some one else had run into this. Yes new tubes are available in seamless, but not in take down configuration. Thanks.
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call turnbull restorations he does 1886 0 -
You are on the right track, however you need to bend it more and let it spring back to straight. It it an art/acquired skill to straighten a tube. A taut silk thread inside is your guide. Practice on something cheap. Everything I have ever seen from turnbull's is top drawer http://www.turnbullmfg.com/ 0 -
If you want to avoid a kink in it when you straighten it fill it with sand or some other fine grained material, perhaps sugar or salt. This non compressive material will keep it from kinking. You can then place it on some type of V blocks or rollers and check it's runout with a dial indicator.
This is the method they use when bending large diameter steel pipe. They can take, say 20" x .250 fill it wit sand and bend a 90 deg with a say... 144" Radius. They then just drain the sand out.
You will need to take extra care when doing this as you will need to make sure you get ALL of the material out after you finish. The three materials I mentioned all have their own drawbacks when it comes to gun parts.
Experiment with some thin walled tubing first, like 1/2" ridged copper tubing. (like you plumb your house with). Good luck. K0 -
Here is something to try but requires extra work. To help prevent seams from opening up when straightening, tightly and closely wrap the tube with soft steel wire the entire length of section to be straightened including pressure point areas. This will not guarantee dent prevention and seam may still tend to open up. Care in placement of pressure points will be required, as is fit of support and pressure blocks (metal straightening is an art form). Also, as was said, overbending to allow for springback is always necessary in metal forming. Flattening or denting the tube is always the danger if a close-fitting mandrel is not inserted inside the tube. Check progress with a straightedge and work slowly. 0 -
The way I'd do it. I'd get a rod (be it steel or wood) that would fit inside the tube. Get it to the point of the warp and push it straight. KeGo slow inch by inch like.
Wraping the outer with wire sounds good but sugar/sand seems messy. I mean it's not like you're forming a condenser on a still.0 -
+1 also stand by with a rubber mallet to tap irregularities out.
Strike against straight hardwood free from dings as you work the rod through.
If you're lucky you can find a standard size rod to fit.
Alternatively, MSC can supply a drill blank in inch and metric sizes.0 -
Y not fill the tube with water and freeze? Then straiten. 0 -
Freezing water expands & would open up the seam. 0 -
Correct, freezing water is a very bad idea. Water reaches it's maximum density at 32.2 degF and from there expands getting colder and warmer. A bit of trivia here. If this were not the case life would be impossible on planet earth. Think about it... Ice would sink and in a very short time (couple of million years) all of the fresh water on plant earth would be sitting frozen on the bottom of the ocean and we would not be here. 0
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