03-03-2020, 09:04 PM
G'day fellas, sorry I haven't been around much over the past month or so, haven't been in the shed much either for that matter. 2020 has not been a good year for us so far. I did finally get the line-boring part of this job finished though. A few photos of the rest of the process...
The end that I had welded back onto the right-hand loader arm was quite a bit out of alignment by the time I had welded all the fish plates on. That made for an interrupted cut for a fair depth before I got the bore round, and the cutting forces in the line-boring process were setting up a lot of wobble in the bench. I attached a temporary brace to the legs of the bench to stiffen it up, part of my tractor splitting stands tacked on as a diagonal member..
That helped a lot but there was still some movement in the job so I added some more scrap metal braces to the bearing carriers...
and that made the setup rigid enough to get the bores done and get a good finish. I had to take the bores out bigger than planned because of the misalignment, the worst of them came out to 1.75" by the time it was round and in line, so I matched them all to that size.
The next challenge was facing the ends of the barrels at 90 degrees to the bore. The proper line-boring setups have a tool for this where the cutter is mounted to a right-angled arrangement on the bar and feeds out like a lathe tool. A bit complex for me. I puzzled over this for a while and came up with the idea of using the surface grinder to put a straight, long cutting edge on the side of a piece of HSS to sweep the face. I put a bit of top rake and a bit of side clearance on the cutter with a flat on the top for the grub screw..
Mounted it in the boring bar..
and promptly snapped it off in the first cut.
I had more success with the second trial but forgot to take photos. Essentially a slightly shorter version of the same tool form, but I cut the face in several steps of around 0.150" each, blending the cut as I went. Came up ok, fit for purpose.
The outer diameter of each barrel has been hardened by the welding, I got out so far with the cutter but then could not cut the stuff around the perimeter. I decided to bevel the outer part away with an angle grinder once I have the job dismounted from the bench.
This setup all worked very well, I guess the next time I have a line-boring job to do it'll be quicker cos I already have all the stuff made for the task.
The end that I had welded back onto the right-hand loader arm was quite a bit out of alignment by the time I had welded all the fish plates on. That made for an interrupted cut for a fair depth before I got the bore round, and the cutting forces in the line-boring process were setting up a lot of wobble in the bench. I attached a temporary brace to the legs of the bench to stiffen it up, part of my tractor splitting stands tacked on as a diagonal member..
That helped a lot but there was still some movement in the job so I added some more scrap metal braces to the bearing carriers...
and that made the setup rigid enough to get the bores done and get a good finish. I had to take the bores out bigger than planned because of the misalignment, the worst of them came out to 1.75" by the time it was round and in line, so I matched them all to that size.
The next challenge was facing the ends of the barrels at 90 degrees to the bore. The proper line-boring setups have a tool for this where the cutter is mounted to a right-angled arrangement on the bar and feeds out like a lathe tool. A bit complex for me. I puzzled over this for a while and came up with the idea of using the surface grinder to put a straight, long cutting edge on the side of a piece of HSS to sweep the face. I put a bit of top rake and a bit of side clearance on the cutter with a flat on the top for the grub screw..
Mounted it in the boring bar..
and promptly snapped it off in the first cut.
I had more success with the second trial but forgot to take photos. Essentially a slightly shorter version of the same tool form, but I cut the face in several steps of around 0.150" each, blending the cut as I went. Came up ok, fit for purpose.
The outer diameter of each barrel has been hardened by the welding, I got out so far with the cutter but then could not cut the stuff around the perimeter. I decided to bevel the outer part away with an angle grinder once I have the job dismounted from the bench.
This setup all worked very well, I guess the next time I have a line-boring job to do it'll be quicker cos I already have all the stuff made for the task.
Lathe (n); a machine tool used in the production of milling machine components.
Milling Machine (n); a machine tool used in the production of lathe components.
Milling Machine (n); a machine tool used in the production of lathe components.