Making a hand crank handle from scratch. [2048x935]

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• (edited ) (+11/-0)

Making a hand crank handle from scratch. [2048x935] (pic8.co)

So, I'm making a "thing" that needs a hand crank handle... you might see the finished thing soon.

Decided to make my own, it uses a combination of wood, copper and steel (machined and forged). Think it turned out pretty well.

The first thing I did was draw up some crude plans:

https://pic8.co/d/bf1bcce8-b0b7-4b97-a58c-a7ee53ba891f.jpg https://pic8.co/d/5825669b-8243-4b56-9cdf-32845717dce5.jpg

Then, the crank. This was made by forging a length of 25x10 steel down (probably would have been better off using 10mm or 12mm square, but didn't have any). The steel was drawn down to a taper in the middle, with the far end tapering in the other dimension to a flat point. The bar is roughly square in the waist section, about 10x10mm.

https://pic8.co/d/89b194dd-47a7-4a11-a2d1-c8d25e5b0aa3.jpg

Then the bar was twisted 90deg and the twist hammered out so it looks like I moved more steel than I actually did.

https://pic8.co/d/77884ea6-9adc-423c-ab78-16a1615d2662.jpg

After a bunch of stuffing around, the tapered bar was scrolled and bent back the opposite direction on the outer part. There's also a compound 'S' curve on the other axis resulting in the handle mount being slightly further out than the center (so you don't smack your wrist on the hub). Hard to describe the overall shape.

https://pic8.co/d/b312e80f-05f8-42e6-bdde-8876375e9075.jpg https://pic8.co/d/8aa6f885-2f9f-4361-b3e1-f27aa01b9cda.jpg https://pic8.co/d/6af0a5d0-39f3-49c7-b39b-45c610bf0e24.jpg

A short section of 1" bar was cut off and faced with a generous chamfer on the outer edge to allow for welding. A 12mm hole and a set screw for securing it were added. The forged crank bar was then welded to the slug with some fairly un-glamourous welds using my old Peerless arc welder.

https://pic8.co/d/11aeac6a-c4ce-4caf-a4a2-4672a48a7ca6.jpg https://pic8.co/d/70ae6628-e816-4dc2-9429-59b35de2892c.jpg

Next was the handle. This was made from Plum wood (from some overgrown branches I pruned a couple of years ago) and some old copper pipe I found at the back of the shed.

https://pic8.co/d/d7548d28-bb67-4cad-a037-3dd8e16d0e64.jpg

The larger copper pipe was used to form the ferrule. A length was cut and trimmed square on a wooden mandrel on the lathe. The mandrel was then trimmed a bit to become the form for hammer forming the end. After a small amount of hammering, the copper work hardens, so I put it in the forge and heated it to red hot, which only took a few seconds to anneal it again. A few annealing cycles were needed to get the form how I wanted it.

https://pic8.co/d/2273517a-fc91-4b98-baa5-a4c065d20906.jpg https://pic8.co/d/25050d94-f937-4407-beff-b702976b903a.jpg https://pic8.co/d/26f2647d-c5f0-4fb7-b3dd-aba4f27a96a1.jpg https://pic8.co/d/6a0a37ed-865c-4b9b-84d3-f013e6632e7e.jpg

The smaller copper pipe was used to form bushes that would act as the bearing surfaces, short lengths were cut and made round using a mandrel with a taper on the end. Copper water pipe is never round. Once that was done, they were cut to length on the lathe.

https://pic8.co/d/300e5bcc-d6ef-4b65-bdc4-a336938b1d33.jpg

The Plum wood branch was first center drilled with a through hole in the drill press. This was ... not very accurate, but left enough meat on the bone to get a handle blank made. Running on a mandrel made from a long 1/4" bolt, I turned down the outer dimension to 26mm, small enough to fit in my biggest 5C collet. This also gave me a chance to play with my new collet chuck adapter in my lathe. The collets are great for holding wood as they don't damage the surface like a normal chuck would. The center was then widened to 9mm with 1/2" counterbores for the copper bushes to lightly press into and an additional 16mm counterbore on the rear end for the screw head to go into. The ferrule was then turned down to be a moderate press fit for the ferrule that I hammer formed (the hammer forming process stretched the pipe by about 1mm).

https://pic8.co/d/a413256a-8a28-4ef9-a38b-f544e492dc9d.jpg https://pic8.co/d/a5d16cda-82cc-4fc5-8a89-332c6cfa28f6.jpg https://pic8.co/d/4c05c1a9-bbae-49f6-98b7-b11a251ea77f.jpg

After the bushes and ferrule were pressed on, the general contour of the handle was turned. This was a simple ~5degree taper from the end of the ferrule to about 2/3 of the way up the handle and a pleasant round over on the end. Sanding with 120, 400, then 1200 grit wet/dry and finishing with Danish Oil completed the handle. It has an excellent feel in the hand, smooth and warm. https://pic8.co/d/6f9a1fe1-7535-4084-96f4-0a73bf30906e.jpg

To mount the handle to the crank, a shaft was turned which had a flange to act as a thrust surface at the base, a 10.5mm boss for the first bush to run on, the remainder of the shaft turned down to 8mm and an M6 thread on the end. The length of the 8mm section was calculated to give about 0.5mm end float when the cap screw is tightened. The cap screw was a flat headed screw with a 15mm head and 10.5mm shank, drilled and tapped M6 to match.

https://pic8.co/d/f557e9a1-7a07-4262-b4af-7fb25b6c0dff.jpg

Originally, I wanted to rivet the shaft on by peening over the end, but that didn't quite work out as well as I wanted, so I ended up welding it. It's not coming off now. All the pieces were assembled, then the completed assembly was fine tuned by mounting it on a 12mm drill shaft in the lathe and using a dial indicator. I managed to get it to something like 0.2mm of runout from parallel to the shaft, which should be fine for a hand crank. The small cracks in the mill scale are from minor adjustments made when the steel was cold. https://pic8.co/d/42dc27d9-9df6-4532-b90f-1b6256fca33e.jpg https://pic8.co/d/efe9fa5b-0c9e-4829-b05f-50a62e98fa47.jpg

So, I'm making a "thing" that needs a hand crank handle... you might see the finished thing soon. Decided to make my own, it uses a combination of wood, copper and steel (machined and forged). Think it turned out pretty well. The first thing I did was draw up some crude plans: https://pic8.co/d/bf1bcce8-b0b7-4b97-a58c-a7ee53ba891f.jpg https://pic8.co/d/5825669b-8243-4b56-9cdf-32845717dce5.jpg Then, the crank. This was made by forging a length of 25x10 steel down (probably would have been better off using 10mm or 12mm square, but didn't have any). The steel was drawn down to a taper in the middle, with the far end tapering in the other dimension to a flat point. The bar is roughly square in the waist section, about 10x10mm. https://pic8.co/d/89b194dd-47a7-4a11-a2d1-c8d25e5b0aa3.jpg Then the bar was twisted 90deg and the twist hammered out so it looks like I moved more steel than I actually did. https://pic8.co/d/77884ea6-9adc-423c-ab78-16a1615d2662.jpg After a bunch of stuffing around, the tapered bar was scrolled and bent back the opposite direction on the outer part. There's also a compound 'S' curve on the other axis resulting in the handle mount being slightly further out than the center (so you don't smack your wrist on the hub). Hard to describe the overall shape. https://pic8.co/d/b312e80f-05f8-42e6-bdde-8876375e9075.jpg https://pic8.co/d/8aa6f885-2f9f-4361-b3e1-f27aa01b9cda.jpg https://pic8.co/d/6af0a5d0-39f3-49c7-b39b-45c610bf0e24.jpg A short section of 1" bar was cut off and faced with a generous chamfer on the outer edge to allow for welding. A 12mm hole and a set screw for securing it were added. The forged crank bar was then welded to the slug with some fairly un-glamourous welds using my old Peerless arc welder. https://pic8.co/d/11aeac6a-c4ce-4caf-a4a2-4672a48a7ca6.jpg https://pic8.co/d/70ae6628-e816-4dc2-9429-59b35de2892c.jpg Next was the handle. This was made from Plum wood (from some overgrown branches I pruned a couple of years ago) and some old copper pipe I found at the back of the shed. https://pic8.co/d/d7548d28-bb67-4cad-a037-3dd8e16d0e64.jpg The larger copper pipe was used to form the ferrule. A length was cut and trimmed square on a wooden mandrel on the lathe. The mandrel was then trimmed a bit to become the form for hammer forming the end. After a small amount of hammering, the copper work hardens, so I put it in the forge and heated it to red hot, which only took a few seconds to anneal it again. A few annealing cycles were needed to get the form how I wanted it. https://pic8.co/d/2273517a-fc91-4b98-baa5-a4c065d20906.jpg https://pic8.co/d/25050d94-f937-4407-beff-b702976b903a.jpg https://pic8.co/d/26f2647d-c5f0-4fb7-b3dd-aba4f27a96a1.jpg https://pic8.co/d/6a0a37ed-865c-4b9b-84d3-f013e6632e7e.jpg The smaller copper pipe was used to form bushes that would act as the bearing surfaces, short lengths were cut and made round using a mandrel with a taper on the end. Copper water pipe is never round. Once that was done, they were cut to length on the lathe. https://pic8.co/d/300e5bcc-d6ef-4b65-bdc4-a336938b1d33.jpg The Plum wood branch was first center drilled with a through hole in the drill press. This was ... not very accurate, but left enough meat on the bone to get a handle blank made. Running on a mandrel made from a long 1/4" bolt, I turned down the outer dimension to 26mm, small enough to fit in my biggest 5C collet. This also gave me a chance to play with my new collet chuck adapter in my lathe. The collets are great for holding wood as they don't damage the surface like a normal chuck would. The center was then widened to 9mm with 1/2" counterbores for the copper bushes to lightly press into and an additional 16mm counterbore on the rear end for the screw head to go into. The ferrule was then turned down to be a moderate press fit for the ferrule that I hammer formed (the hammer forming process stretched the pipe by about 1mm). https://pic8.co/d/a413256a-8a28-4ef9-a38b-f544e492dc9d.jpg https://pic8.co/d/a5d16cda-82cc-4fc5-8a89-332c6cfa28f6.jpg https://pic8.co/d/4c05c1a9-bbae-49f6-98b7-b11a251ea77f.jpg After the bushes and ferrule were pressed on, the general contour of the handle was turned. This was a simple ~5degree taper from the end of the ferrule to about 2/3 of the way up the handle and a pleasant round over on the end. Sanding with 120, 400, then 1200 grit wet/dry and finishing with Danish Oil completed the handle. It has an excellent feel in the hand, smooth and warm. https://pic8.co/d/6f9a1fe1-7535-4084-96f4-0a73bf30906e.jpg To mount the handle to the crank, a shaft was turned which had a flange to act as a thrust surface at the base, a 10.5mm boss for the first bush to run on, the remainder of the shaft turned down to 8mm and an M6 thread on the end. The length of the 8mm section was calculated to give about 0.5mm end float when the cap screw is tightened. The cap screw was a flat headed screw with a 15mm head and 10.5mm shank, drilled and tapped M6 to match. https://pic8.co/d/f557e9a1-7a07-4262-b4af-7fb25b6c0dff.jpg Originally, I wanted to rivet the shaft on by peening over the end, but that didn't quite work out as well as I wanted, so I ended up welding it. It's not coming off now. All the pieces were assembled, then the completed assembly was fine tuned by mounting it on a 12mm drill shaft in the lathe and using a dial indicator. I managed to get it to something like 0.2mm of runout from parallel to the shaft, which should be fine for a hand crank. The small cracks in the mill scale are from minor adjustments made when the steel was cold. https://pic8.co/d/42dc27d9-9df6-4532-b90f-1b6256fca33e.jpg https://pic8.co/d/efe9fa5b-0c9e-4829-b05f-50a62e98fa47.jpg

(post is archived)