Dave (et al.). I found an old chain drill for sale online, but I'm not sure it's what you mentioned, and in any case I can't figure out what it's good for or how it is used. Have you got the patience to school me?
Thanks.
(Mr. G, thanks also for the adjustable-angle drill pics. Another objet I didn't know I didn't know about.)
Well, the chain drill isn't good for anything much nowadays but what you would do is chuck the device into a bit brace or, preferably, a chest drill, chuck an auger bit into it and line the bit up where you want your hole, loop that chain around the work once (I tried it on an 8 x 8 post) and lock it in place. Then you would turn the knob to tighten the bit into the work (mine lacks that feature; you have to crank the drill but I'm going to go take a look and see if I missed something). As you crank the brace or drill, the threads take up against the "arms" holding the chain and the auger begins to feed into the work. I can't really call it "self feeding" because you have to crank like hell to drill a hole. But it does hold the bit into the work, and relatively straight. And when you need to take a break, you can just let go of the drill and the whole shebang stays in place. waiting for you to start cranking again. I can imagine them being used for timber framing, maybe by apprentices but experienced framers probably didn't bother.
A modern-day equivalent would be the (electro) magnet drill, which we use for drilling into thick steel in the field. The same principle, but you can enjoy a cup of coffee while the magnet drill does the work.
Here's a drawing of the exact setup that I have (hanging on the wall, not drilling holes!):
Thanks, it's all clear to me now. (I originally typed "It all makes sense now," but that isn't exactly so.) I decline to invoke Rube Goldberg, but the chain drill does look like a "transitional technology."
6 comments:
I found one of those at a garage sale, along with a "chain drill" attachment. Neither are a joy to use, but they make good wall-hangings.
It is impressive what they came up with back in the day though.
Dave (et al.). I found an old chain drill for sale online, but I'm not sure it's what you mentioned, and in any case I can't figure out what it's good for or how it is used. Have you got the patience to school me?
Thanks.
(Mr. G, thanks also for the adjustable-angle drill pics. Another objet I didn't know I didn't know about.)
Grr. Let's see if the eBay chain drill URL stays put this time.
https://www.ebay.com/itm/264449280029
Well, the chain drill isn't good for anything much nowadays but what you would do is chuck the device into a bit brace or, preferably, a chest drill, chuck an auger bit into it and line the bit up where you want your hole, loop that chain around the work once (I tried it on an 8 x 8 post) and lock it in place. Then you would turn the knob to tighten the bit into the work (mine lacks that feature; you have to crank the drill but I'm going to go take a look and see if I missed something). As you crank the brace or drill, the threads take up against the "arms" holding the chain and the auger begins to feed into the work. I can't really call it "self feeding" because you have to crank like hell to drill a hole. But it does hold the bit into the work, and relatively straight. And when you need to take a break, you can just let go of the drill and the whole shebang stays in place. waiting for you to start cranking again. I can imagine them being used for timber framing, maybe by apprentices but experienced framers probably didn't bother.
A modern-day equivalent would be the (electro) magnet drill, which we use for drilling into thick steel in the field. The same principle, but you can enjoy a cup of coffee while the magnet drill does the work.
Here's a drawing of the exact setup that I have (hanging on the wall, not drilling holes!):
https://3.bp.blogspot.com/-8Dth1pd1vwk/WjCK6MHPuNI/AAAAAAAAMao/UKBmLZCI0-EcN9HU7MCw15qGxpAgiTclgCLcBGAs/s1600/bd25larg.jpghttps://3.bp.blogspot.com/-8Dth1pd1vwk/WjCK6MHPuNI/AAAAAAAAMao/UKBmLZCI0-EcN9HU7MCw15qGxpAgiTclgCLcBGAs/s1600/bd25larg.jpg
I would be interesting to figure out how much energy goes into making chips and how much goes into overcoming mechanical losses.
Sorry; this is the second time recently I double-pasted an image link. It should be:
https://3.bp.blogspot.com/-8Dth1pd1vwk/WjCK6MHPuNI/AAAAAAAAMao/UKBmLZCI0-EcN9HU7MCw15qGxpAgiTclgCLcBGAs/s1600/bd25larg.jp
Thanks, it's all clear to me now. (I originally typed "It all makes sense now," but that isn't exactly so.) I decline to invoke Rube Goldberg, but the chain drill does look like a "transitional technology."
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