09-22-2013, 05:45 PM
Some months ago, my favourite tool store had a 6" 4-jaw chuck on sale for $65. I had been thinking about replacing the worn out one on my Hercus (SB9A) lathe, so it seemed like the ideal opportunity.
Turns out that not too many suppliers sell 6 1/4" backplates with 1 1/2" x 8 spindle threads. That's what the diameter of the chuck actually is. I tried to find one on-line, to no avail. Several trips to the scrappers didn't net me an appropriate piece of metal to make one. I even considered casting one from aluminum.
In the meantime, I wired a new shop for one of the owners of the scrap yard - a 3500 square foot addition to his garage. He (Kelly) was quite pleased with the result. During the construction, I went to the yard a few times to browse. On one trip, I noticed some broken pieces of cast iron that could come in handy. Kelly says, "Throw them on your bike." Last trip, I found another piece from the same parent chunk that was about 1 1/2" thick and very large. I was heading for the scale and Kelly says, "Throw it in your van. It's a tip for the good job." The two top pieces (and one thicker one that missed photo day) were from the first trip. The big one was from the last trip.
[attachment=6604]
It takes a bit of cutting to get a 6 1/2" circle out of a piece that's too big for a 9 x 12 bandsaw.
[attachment=6605]
With the blank bolted to the faceplate, the spindle side is faced and bored first.
[attachment=6607]
Then the centre is threaded for the spindle.
[attachment=6608]
After that, the piece is removed from the faceplate and the other side is faced and the register step cut.
[attachment=6609]
Back to the rotary table on the Victoria for drilling and counterboring the bolt holes.
[attachment=6610]
I'm quite pleased with the results. The rim of the backplate shows a TIR of less than 0.0005" and the body of the chuck shows a TIR of 0.002".
[attachment=6611]
[attachment=6612]
Turns out that not too many suppliers sell 6 1/4" backplates with 1 1/2" x 8 spindle threads. That's what the diameter of the chuck actually is. I tried to find one on-line, to no avail. Several trips to the scrappers didn't net me an appropriate piece of metal to make one. I even considered casting one from aluminum.
In the meantime, I wired a new shop for one of the owners of the scrap yard - a 3500 square foot addition to his garage. He (Kelly) was quite pleased with the result. During the construction, I went to the yard a few times to browse. On one trip, I noticed some broken pieces of cast iron that could come in handy. Kelly says, "Throw them on your bike." Last trip, I found another piece from the same parent chunk that was about 1 1/2" thick and very large. I was heading for the scale and Kelly says, "Throw it in your van. It's a tip for the good job." The two top pieces (and one thicker one that missed photo day) were from the first trip. The big one was from the last trip.
[attachment=6604]
It takes a bit of cutting to get a 6 1/2" circle out of a piece that's too big for a 9 x 12 bandsaw.
[attachment=6605]
With the blank bolted to the faceplate, the spindle side is faced and bored first.
[attachment=6607]
Then the centre is threaded for the spindle.
[attachment=6608]
After that, the piece is removed from the faceplate and the other side is faced and the register step cut.
[attachment=6609]
Back to the rotary table on the Victoria for drilling and counterboring the bolt holes.
[attachment=6610]
I'm quite pleased with the results. The rim of the backplate shows a TIR of less than 0.0005" and the body of the chuck shows a TIR of 0.002".
[attachment=6611]
[attachment=6612]