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While smoothing up the ratchet of the new cylinder recently fit the main spring gave out so spent most of last evening filing/grinding out a new one,hardening and tempering it.
I should have taken some pictures along the way but once I start making metal chips and filings it hard for me to stop and mess around with picture taking.
Now that I'm ready to describe how it was done I see the need for pictures to relate the more difficult areas to negotiate. One would think a one leaf, curved flat spring would be very simple but is actually quite complicated as length, curve profile and heat treat have to be correct or one starts over again.
Guess I'll go back out in the shop and take some pictures like I should have last night.
The broken spring was annealed and curve removed so I could lay the shape out on the flat spring stock which .500 wide by .062 thick.
The general shape was formed on my bench grinder being careful not to make it to small.
This spring had to have a hammer roller trough filed in the top end so it will track down center and not veer off to the side.
The trough has to start out pretty much level with the roller contact and most of the spring action is a down ward bend with very little rear ward movement. If not level when the bend is started then the tip of the spring wants to move forward and bind at the hammer purchase base ahead of the roller.
The lower spring seat on the frame is angled to tension the main spring body to the rear and also to secure the flat head screw around the entire perimeter of the purchase hole. If this is not draw up firmly against the underside of the flat head purchase screw then the spring bends through the hole and will quickly fail.
The proper profile of the bend is trial and error until it looks and feels right then the heat treat is 1500 F for about 20 minutes, quench in oil and I draw the temper using an old black smith method I pick up decades ago that has never failed me and I've made a lot of springs over 40 plus years.
Click on picture to enlarge.
One finds a flat lid of some kind, deep enough so that a 50-50 mix of 30 wt motor oil and Kerosene will cover it laying on it's side, take it out side out of the wind and lite with a propane torch. Let it burn out and it will be perfectly tempered.
I should have taken some pictures along the way but once I start making metal chips and filings it hard for me to stop and mess around with picture taking.
Now that I'm ready to describe how it was done I see the need for pictures to relate the more difficult areas to negotiate. One would think a one leaf, curved flat spring would be very simple but is actually quite complicated as length, curve profile and heat treat have to be correct or one starts over again.
Guess I'll go back out in the shop and take some pictures like I should have last night.
The broken spring was annealed and curve removed so I could lay the shape out on the flat spring stock which .500 wide by .062 thick.
The general shape was formed on my bench grinder being careful not to make it to small.
This spring had to have a hammer roller trough filed in the top end so it will track down center and not veer off to the side.
The trough has to start out pretty much level with the roller contact and most of the spring action is a down ward bend with very little rear ward movement. If not level when the bend is started then the tip of the spring wants to move forward and bind at the hammer purchase base ahead of the roller.
The lower spring seat on the frame is angled to tension the main spring body to the rear and also to secure the flat head screw around the entire perimeter of the purchase hole. If this is not draw up firmly against the underside of the flat head purchase screw then the spring bends through the hole and will quickly fail.
The proper profile of the bend is trial and error until it looks and feels right then the heat treat is 1500 F for about 20 minutes, quench in oil and I draw the temper using an old black smith method I pick up decades ago that has never failed me and I've made a lot of springs over 40 plus years.
Click on picture to enlarge.
One finds a flat lid of some kind, deep enough so that a 50-50 mix of 30 wt motor oil and Kerosene will cover it laying on it's side, take it out side out of the wind and lite with a propane torch. Let it burn out and it will be perfectly tempered.
but you do nice work and it’s evident that you care about it.
)
