This is probably old news to the pros out there, but for basement wannabes slaving over away in our spare time, I think Pacific Tool and Gauge has come up with a solution to a job I just hate to do: turning down stock bolt handles and threading them to accept oversize bolt knobs. Until recently, turning down a bolt knob and threading it for an oversize knob has been a tricky and time consuming process. I saw a great video of a 'hide smith use a custom fixture on a very large Bridgeport mill do it in less than 3 minutes using a roughing mill to remove excess metal, a hollow mill to size the stub, and an automatic threading device to thread the stub. Of course, not having a mill twice the size as mine, a DRO, or a threading device I was stuck with using a grinder, a boring head in my (smaller) mill, and a hand die to thread the stub. It worked, but it took too damned long.
Last year or so, Pacific Tool And Gauge introduced what is now known as the Phase I bolt knob fixture designed for a lathe. The bolt was placed in the proper alignement in the fixture in a three jaw chuck and the bolt handle cut down to a proper diameter stub for threading:
The hollow end mill in the second image comes with the fixture and is referred to as a "slugger" than mounts in a chuck in the lathe tailstock. When I got my first fixture, I did not get the slugger; either it wasn't available yet or it was more than I could afford. I was therefore concerned that using a single point tool to reduce the bolt handle would cause a soldered bolt handle joint to fail; there was nothing to isolate the bolt handle/bolt body joint from the stresses of machining. Despite removing as much metal as prudent with a bench grinder, the first bolt I worked on, a bolt from a Remington 700 Long Action, gave a resounding "PING" after only a few turns with the infeed set a +.005". I called Dave at PTG and we discussed the need for some way of isolating the joint from machining stresses, and I ended up ordering one of the hollow "slugger" end mills an set the fixture to the side while I contemplated how to modify it to keep more bolt handles from flying off in the future. Dave also recommended an excellent 'smith who timed the handle, put a nice little TIG weld at the rear to hold the handle in place while he silver soldered it back on. I gotta learn how to do that.
Recently, I was on the PTG website ad noticed their Phase II Bolt Fixture for a lathe, as well as a fixture to use in a mill. The Lathe Fixture looked like it was an answer to the stress isolation problem:
Once the bolt is mounted in the grooves and top plate bolted down, the bolt handle is clamped firmly along the centerline of the lathe, protecting the solderjoint of the bolt handle to the bolt body. Looks pretty good, and I plan on giving it a test in the next week or so. I'll shoot a little bit of video to show the result, but I'm pretty optimistic about it;; I think PTG has come up with an affordable and reliable fixture for modifying stock bolt handles to accept oversize knobs.
It's almost like we're living in the 21st century : )
Sent from my iPad using Tapatalk HD
Last year or so, Pacific Tool And Gauge introduced what is now known as the Phase I bolt knob fixture designed for a lathe. The bolt was placed in the proper alignement in the fixture in a three jaw chuck and the bolt handle cut down to a proper diameter stub for threading:
The hollow end mill in the second image comes with the fixture and is referred to as a "slugger" than mounts in a chuck in the lathe tailstock. When I got my first fixture, I did not get the slugger; either it wasn't available yet or it was more than I could afford. I was therefore concerned that using a single point tool to reduce the bolt handle would cause a soldered bolt handle joint to fail; there was nothing to isolate the bolt handle/bolt body joint from the stresses of machining. Despite removing as much metal as prudent with a bench grinder, the first bolt I worked on, a bolt from a Remington 700 Long Action, gave a resounding "PING" after only a few turns with the infeed set a +.005". I called Dave at PTG and we discussed the need for some way of isolating the joint from machining stresses, and I ended up ordering one of the hollow "slugger" end mills an set the fixture to the side while I contemplated how to modify it to keep more bolt handles from flying off in the future. Dave also recommended an excellent 'smith who timed the handle, put a nice little TIG weld at the rear to hold the handle in place while he silver soldered it back on. I gotta learn how to do that.
Recently, I was on the PTG website ad noticed their Phase II Bolt Fixture for a lathe, as well as a fixture to use in a mill. The Lathe Fixture looked like it was an answer to the stress isolation problem:
Once the bolt is mounted in the grooves and top plate bolted down, the bolt handle is clamped firmly along the centerline of the lathe, protecting the solderjoint of the bolt handle to the bolt body. Looks pretty good, and I plan on giving it a test in the next week or so. I'll shoot a little bit of video to show the result, but I'm pretty optimistic about it;; I think PTG has come up with an affordable and reliable fixture for modifying stock bolt handles to accept oversize knobs.
It's almost like we're living in the 21st century : )
Sent from my iPad using Tapatalk HD
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