kcsmith,
I'm not familiar with your bolt so I'm going to use mine from a Springfield MK2. Mine is from 1935 and has a "B" suffix.
If you look at the bolt the first thing you will notice is that there is almost no witness marks from rubbing against adjacent
surfaces. I would estimate the bolt shaft itself has less than .005" clearance. The clearance to lug number two varies between
.010" and .025". The only high force and high wear area would be on the back of the lug with a
red dot on it. That position
has a hardened round plug installed to rub against the cam area in the receiver that drives the bolt forward upon CW rotation
of the bolt handle.
I would guess that your bolt is correct with the design clearances it has. Many of my bolts are fairly loose until they reach a critical
position that is likely in the final 1/8" of it's forward most position. At it's full forward position, the bolt is locked up tight
and true.
Images 7 and 8 are of an Olympic FWB P70 HP FT air rifle. The sliding breach block that has the air transfer port is pretty sloppy
when in the open position. When it is closed the transfer port needs to be lined up and the breach needs to seal against the barrel
in front and a seal under the breach block to allow air to flow. It can't be loose because 1500 psi of air needs drive the pellet out.
It is only when the breach is fully closed and the male and female cone align that allow this design to work at all.
It's a good illustration of a loose design that tightens up when it needs to.
I doubt the SURFACES you pointed out see any load to speak of. If it were 1922, they wouldn't. Those appear to be upper and
side surfaces not an axial surface that see's any thrust load.
To answere your welding question, since TIG is readily available as is hard surfacing / hard facing rod, that is what I would use
if I were personally doing it.
It sounds like when you say" Binding" , you mean as you cycle the bolt forward and aft the bolt is getting a little off
axis. If that
is the case, I don't think any kind of lug work would reduce that.
FYI... There is a process called "Spray welding" that is used to build up the surfaces of worn shafting and other parts. The part is generally
spun and welding material is sprayed onto it. A secondary grinding operation is required to bring it back into the design dimension.
Still nothing that will help your case. About 1980, I had seen an apple that had been spray welded. Why? I don't know... why did they twist the
barrel on the FWB 65 pistol below. 5 or 6 of them actually. I like the last image best for thermal spray welding. A crank shaft is undersized
for some reason and they are building it up to salvage it. In that case they are using a plasma heat source.
On my 1922 shown in the third image labeled 2.jpg, it wouldn't make any difference in function if the surface was ground down by .06"
You can see that the surface with the green dot has ZERO wear on it because it clears by at least .010"alreay.
btw... 308 is correct, there is a differences between tolerances and clearances but he need not be such a flaming Nimrod about it.
I excuse it because it's semantics. The average guy on this forum doesn't know or even need to know the difference. Your query
was perfectly clear to me. TIGHTEN THINGS UP WITH WELD.
Your question about laser or TIG is really about the best process to use. He wont do it himself or he would not be asking the question.
If it is electron beam welding, that is all he wants to hear. The best process.
I have manually welded SS with TIG. ( GTAW ) The weld was a fillet fusion and the weld size being about .040" and very little HAZ. I would have
little concern about adding some hard facing to a surface and then have it sent out to be reground. Do I still weld for a living? No!
I was able to do the welds because I had surface ground every surface of the 3/8" thick SS prior to welding. My welds were very straight
and glassy smooth with no weave. The ones below are very nice... mine had a very different texture. The last thing I welded was 4130
air foil profile tube for landing gear. I used some local welding rod and the results were imperfect. I think that was about $3.00 a pound.
I decided to get some MC grade rod from Lancaster Alloys in CA. As I recall it was $30.00 a pound and free of the copper coating found on
most filler rod. The welds became perfect !! The welds were in plain sight and my name was going to be attached to them forever.
That must have been in 2002.
Because it was surface ground, there was virtually no gap to fill and no filler rod to add. I kept the assembly true and square with 1x2x3 blocks and
because of my tack placement, I was able to remove the 1x2x3 block without putting a single scratch on the ground surface's and then
put it back in place. I had to stop and start a few times but it was undetectable. All of my welds and HAZ had very pretty colors like
the weld below. It wasn't a structural piece... it was basically a desk top trophy that would hold a small plaque and a mechanical
pencil that Tony had used for about 40 years while at the company.
When I went to school, brazing and welding were two distinct process's. We would never say "Brazewelding" Brazing is done below the
melting point of the parent metal and welding actually fuses the parent metal with or without filler. If the parent doesn't melt than it isn't welding.
It's brazing, silver soldering..... bonding. That said... a silver soldered joint with a .003" gap has a tensile strength of 50 / 55K psi.
Even if you are new to welding, or have been at it for a while, you may have heard of the term ‘brazing’ or ‘braze welding,’ and may wondered what it is.
weldingheadquarters.com
Don't weld your lugs and learn all you can your entire life.