Ok - boiler build time!
The second attempt at the boiler bolt ring using 304 stainless M10 set screws. The previous attempt (no picture at the moment) involved brazing socket head cap screws in place. This proved problematic: I ran out of gas (not once, but twice) while attempting to braze them in place with a toy oxy-acetylene torch from the hardware store. I then attempted to finish the brazing using my TIG torch as heat source - which, while technically possible, was, in the hands of this welder, not a good idea. Lot of swearing that day. :o Since then, I have finally succumbed and added a real oxy-acetylene setup to the shop.
The biggest problem with cutting the holes in the boiler was holding the 6" diameter pipe in the mill. I finally decided to tack weld the ends in place to give the pipe itself enough rigidity during machining.
Even having done this, I couldn't get enough clamping pressure and holding force (without spending a day or two on building a jig) to prevent the whole part from lifting when cutting the holes with an end mill. So dumb drilling it had to be. First a centre-drill.
Then I work my way up through drill bits by about a 1/16" at a time...
...till I get to 3/4". I would have built a jig, but I think that I may well be able to have the boiler tube pre-cut with on a laser tube cutter, so I will hold off until I have a better understanding of the requirements.
Image of the holding setup. It was enough to keep the assembly from moving laterally, but didn't generate enough friction from stopping the boiler from lifting when using the end mill...
First row of holes complete and I use a pointed brass spud for a visual alignment of the next bunch. The lead-free fittings that I cut on the lathe are dry-fit for now. I like to mark out the placement with a Sharpie by hand before drilling to avoid the painful forehead slap on the discovery that the part was placed backwards in the vice and consequently the holes are in the wrong place.
A little cleanup with a deburring tool and we are done!
The second attempt at the boiler bolt ring using 304 stainless M10 set screws. The previous attempt (no picture at the moment) involved brazing socket head cap screws in place. This proved problematic: I ran out of gas (not once, but twice) while attempting to braze them in place with a toy oxy-acetylene torch from the hardware store. I then attempted to finish the brazing using my TIG torch as heat source - which, while technically possible, was, in the hands of this welder, not a good idea. Lot of swearing that day. :o Since then, I have finally succumbed and added a real oxy-acetylene setup to the shop.
The biggest problem with cutting the holes in the boiler was holding the 6" diameter pipe in the mill. I finally decided to tack weld the ends in place to give the pipe itself enough rigidity during machining.
Even having done this, I couldn't get enough clamping pressure and holding force (without spending a day or two on building a jig) to prevent the whole part from lifting when cutting the holes with an end mill. So dumb drilling it had to be. First a centre-drill.
Then I work my way up through drill bits by about a 1/16" at a time...
...till I get to 3/4". I would have built a jig, but I think that I may well be able to have the boiler tube pre-cut with on a laser tube cutter, so I will hold off until I have a better understanding of the requirements.
Image of the holding setup. It was enough to keep the assembly from moving laterally, but didn't generate enough friction from stopping the boiler from lifting when using the end mill...
First row of holes complete and I use a pointed brass spud for a visual alignment of the next bunch. The lead-free fittings that I cut on the lathe are dry-fit for now. I like to mark out the placement with a Sharpie by hand before drilling to avoid the painful forehead slap on the discovery that the part was placed backwards in the vice and consequently the holes are in the wrong place.
A little cleanup with a deburring tool and we are done!
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