... unless your wife is at home in the kitchen!Interesting that its possible to temper the spring at only 400 F. That is very manageable for a home hobbyist.
... unless your wife is at home in the kitchen!Interesting that its possible to temper the spring at only 400 F. That is very manageable for a home hobbyist.
Luckily, my girlfriend is very pro arts and crafts (all the power tools are hers) and I am the main cook.... unless your wife is at home in the kitchen!
Correct.... unless your wife is at home in the kitchen!
Would you consider this an achievable project with hand tools?Lessons learned building the wheel lock per Lauber's book.
The prints are suggestions, not hard and fast rules. Expect to deviate from them.
Convert the prints back to metric if you can work in metric units.
You will find most of the numbers are even mm or simple fractions of a mm.
You will also realize quickly that a lot of the dimensions are not a critical as the 0.001 precision of the text would imply.
Carefully fit the mating features.
Don't sweat the features that mate with air.
I had access to a milling machine and metal lathe, welding and gas cutting equipment for this project, which simplified the process.
Build from the wheel out.
I built a mandrill to drive the wheel in my mill and used the hardened wheel to cut the notch in the bottom of the powder pan.
I laid out the profile of the lock plate, but did not cut away any more than I had to until near the end. Having parallelly sides and a 90 degree corner made layout easier and made it simpler to reposition it in the mill vise. The outside profile is not a critical feature and you may have to tweak it at the end.
To make the chain links, I welded together a stack of thin sheets. Then drilled and filed most of the profile as a set. Applied superglue to the stack. Then cut away the welds and finished the profile. Once the profile was done I separated the stack of links and added countersinks and polished.
The pins in the chain gave me fits. They kept upsetting and locking up the links.
I finally made pins with a small countersunk hole in the ends and then the pin ends were faired using an automatic center punch.
After assembly I rubbed the chain with a dab of lapping compound and worked it a few times to get it moving freely.
The toggle on the end of my chain was made in the lathe by turning a disk with pins on both sides, and then parting the assembly from the bar. The concentric pins were the hard part. After that it was just a matter of filing the profile and setting the hole so the chain did not bind on the main spring.
I machined the bridle without the hole for the spindle. Then I mounted the lock plate in the mill, dialed in the hole for the spindle, and mounted the bridal and drilled the hole without moving the lock plate.
The spindle is also the cam for the pan cover.
You should put a center punch mark on one of the flats of the square shaft and a timing mark on the wheel. I cant tell you how many times I took that lock apart.
Do not cut the cam to open the pan cover until you have completed the sear system in the lock. Depending on the exact fit of your chain and main spring the timing of the cam may be a bitt different than the plans assume.
Also the lever that moved the pan cover was too light and bent from its own inertia.
Use a barrel with a lot of width at the breach or increase the internal thickness of the pan cover an pan. The ram rod is under the center of the barrel and the lock is thick. The pan sandwiches against the barrel at the touch hole. If the inside edge of the bridal is too close to the center line of the barrel, you cant fit a ram rod behind it.
I built a custom cutter to make the pins on the tabs that hold the main spring, and fitted the pins precisely to the holes in the lock plate. This was probably overkill. The pins on those tabs are just rivets and will upset into the lock plate and fill the hole when you peen them with a small ball peen hammer.
My small springs were made from a worn out 1 1/8 inch metal cutting band saw blade. They are thicker than a home shop size blade.
I used the same stuff for the small sear.
The large sear needs to be hardened at the ends or the ball and small sear will cut into it. Its nice to have the center ductile so you can bend it a bit if you oops on the fit.
I think a more generous radius on the tight bend of the main spring and thicker bracket (capable of holding a thicker small sear) would be an improvement. The small sear works, but thicker would probably be a bit more robust.
I had difficulty getting the pan cover to move far enough and had to open up the clearance between the pan cover and plate it runs on near the front of the lock.
There are several pins in blind holes. I made my tiny pins from salvaged springs, and put 90 deg bends on some with mating notches so I could get them out of blind holes.
The lock has a lot of small tapped holes.
Buy the right size drills and top of the line taps - not that cheep junk sold at the big box stores. You don't want to get 3/4 through and snap a tap in your lock plate.
Be very careful about the fit of the pan cover. The ball detent that locks the wheel pushes the wheel into the outside of the slot in the pan cover. If you have play in this part of the system, you may not get the sear to hold properly.
A good selection of files is a must.
These locks were made by hand and a lot of the profiles can be roughed in with machine tools, but the final forms are better suited to filing. Big course files for stock removal and small fine toothed files for the final finishing before polishing.
I did make a set of flat topped smooth unhardened jaws for my bench vise. I also mounted a magnifying light next to the vise to help with filing parts to a scribed line. I am considering mounting the vise with a small tilt back so its easier to see the scribed line as I file.
Thank you for providing detailed advice from first hand experience!I have played on the blacksmiths forge for over 35 years, and some of the parts can be forged and filed to shape.
No matter how you do it, the dog takes a lot of filing.
The plans I found on line called for the dog to be brazed up from 3 parts and the geometry in the plans is set up for that.
If you look at the period examples in this thread, the form of the dog is better suted to forging and filing.
If you forge the dog, I recomend completing it, except for the toes that engage the dog spring. Leave that area unfiled.
Clamp in your pyrite, and position the dog so it clears the pan cover, and the pyrite engages the wheel without interferance from the pan or cover, then mark the hole for the dog to mount to the lock plate, and drill and tap the lock plate. Its fussier than you might expect.
The dog mounts to the front of the lock and does not mechanicaly engage with anyting inside the lock plate, so the mount hole position is only critical for engagement with the wheel.
Once the dog is positioned, make the V spring that pushes it into the wheel and mount it.
I recomend a slightly wider opening in the V than what were in the plans I found.
That allows for a longer foot on the dog and its easier to fit it. It aslo gives the spring a bit longer of a lever to push on and force the pyrite into the rotating wheel.
Its easy to take off metal if it pushes too hard, but you cant add it if the spring fully closes and the foot wont pass.
As in my earlyer notes, file the final profile of the lock plate after everything is fitted and running. It mates with wood that will be carved later, so it just had to be appealing to the eye, not an exact match to the plans. That basic techniqe is an option for making the wheel by hand. Slow, but accurate enough for this project.
A ball mill is the easy way to cut the dish in the pan, but it would also be very easy to forge it by driving the pan over a round rod or fuller and then filing the rest of the form.
The springs have to be forged to get the curves.
I used simple hardwood forms to match the geometry in the plans.
Sure they smoke a bit, but for one use they are fine.
The chain is hard to do without at least a drill press and vise to make the holes.
The holes need to square to face of the link and match center to center or it just wont run smoothly.
The outer profile is just a matter of filing carefully.
If you have access to a lathe, a couple of heat treated rollers with a hole the same size as your pin hole mounted to each side of the links allow one to file the curve without any real effort or skill.
Alternately a sacrificial jaw in your bench vise with a notch that supports a pin fitted to allow the outside edge of the link to rotate at the top edge of the jaws allows easy material removal to the vise jaw. Just reposition a few times to get it near round and touch up the last of it by eye.
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