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I'm interested in building a traditional bow-lathe, specifically of the type still used in parts of North Africa, a few videos of which can be found on YouTube.

The problem is that I can't really figure out how the mechanism for moving the two centers closer together works, aside from it seeming to use wedges in some capacity.

If anyone has any information it would be greatly appreciated.

to further clarify what im talking about, i'll link some pictures and videos below.

https://youtu.be/wnv0DAR_gWA https://youtu.be/RMQrz1gJy9M

these videos, both from Morocco, show these devices in action, and are rather impressive in my opinion, but the details of the lathe itself are somewhat obscured by chips and the turner's themselves. Here are some of the best close-up images ive been able to find of a similar lathes.

https://2.bp.blogspot.com/-To97wy-WU-o/TpMEKgb-d-I/AAAAAAAAArU/Zfp6G-Kkhpg/s1600/Artisan+%25234.jpg

https://2.bp.blogspot.com/-UbVKXjpebSk/UnOHyNXGS-I/AAAAAAAAAOc/a4Sh-Jt4qYo/s1600/P1110859.JPG

https://i.stack.imgur.com/GbN9z.jpg

https://2.bp.blogspot.com/-4G5eJPO4dek/WvMfYzOlWGI/AAAAAAAAB_Y/68koyB7VZIoHDFMy-RtLmicSG3Z4UpboACEwYBhgL/s1600/P1190313%2Br.jpg

The wedges I was referring to can be seen in the last image, but this is a somewhat different design.

reciprocalmotionenjoyer
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  • Hi, welcome to StackExchange. There's a long tradition of these from Europe (and the US) as well and the build details of these could be easier for you to copy since they seem to be largely built from standard boards, AKA dimensional lumber. The wedges are just used as locks, to fix head and tailstocks once slid into position along the bed. Using wedges in this way is also something with a long tradition in Europe and subsequently in America, as well as in other woodworking traditions. – Graphus Mar 03 '22 at 02:10
  • What are your goals with this lathe? If you want to do more than fairly basic turning in green wood perhaps something else would be a better route for you to explore. – Graphus Mar 03 '22 at 02:11
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    Link to videos you have watched? I searched on YouTube, found only one and it had no wedges!! – Volfram K Mar 03 '22 at 05:54
  • Having not watched any videos (except, perhaps an episode or two of The Woodwright's Shop on PBS 25+ years ago) on bow-lathes, I'd venture to say the tail stock slides in a long, loose dovetail so it can be moved into position, then is held there by driving a wedge to jam it into position. Note that you can find episodes of TWS on-line today. I'm not sure if any of the bow-lathe episodes are there, but it may be worth a search, as Roy usually described how the tools worked in addition to showing them in use. – FreeMan Mar 03 '22 at 14:05
  • @FreeMan, there's a pretty comprehensive article on Pop Woodworking on Roy's springpole lathe, but I think it's actually quite a different animal to what the OP is asking about. – Graphus Mar 03 '22 at 19:45
  • That was all from memory and my memory may have been wrong. I wouldn't be too shocked, however, for the beds to adjust in a similar fashion. – FreeMan Mar 03 '22 at 20:39
  • @graphus Thanks! I haven't heard about anything like this in America or Europe, though they presumably existed in Iberia and other areas under Islamic influence, but in all fairness I cant find much documentation across the board, as these seem to usually be rustic, work-oriented devices, existing in the background in some form since ancient times. In any case, i'd love to read anything you might have about the subject. – reciprocalmotionenjoyer Mar 04 '22 at 00:44
  • @Graphus I pretty much just want to make rosary beads, some handles for knives and files, and maybe some game pieces. I'm a machining student, so I have (rather time-limited) access to metal lathes, but im drawn to antiquity, and tend to be a slow worker. – reciprocalmotionenjoyer Mar 04 '22 at 00:50
  • @FreeMan sorry for any confusion, hopefully i've cleared things up better with the edit I made to my post. the tusked mortise-like design seems to be used on basically every spring-pole lathe i've seen, and is a lot easier to understand, but due to space concerns, and especially due to the currently prohibitive cost of lumber where im at, copying the people of the deserts seems like a good strategy. – reciprocalmotionenjoyer Mar 04 '22 at 00:59
  • No worries! The confusion was on my part - you said one thing and I thought another. – FreeMan Mar 04 '22 at 12:17
  • Thanks for the updates, they are a huge help. As to your original query about wedges, these are basically used in woodworking as frictional locking devices. Once you know this you can generally figure out how any given wedge is acting by just looking at its location — where's the thick end, where's the thin, bingo, there's your answer. – Graphus Mar 04 '22 at 16:06
  • Now as to what you want to actually produce on your future lathe, this won't tickle your admiration for technology of antiquity but I would give strong strong consideration to making a drill-powered lathe instead. I'm just finalising details of a drill-based lathe myself after seeing a friend's interpretation of Patrick Sullivan's "Disappearing Lathe" from YouTube and trust me when I tell you it would be far more efficient and productive! Use of materials can be quite modest — you can build one 99% from OSB if necessary, the price of which hopefully hasn't risen too high where you are. – Graphus Mar 04 '22 at 16:11
  • @Graphus I think its just a general failure of comprehension on my part, and the misinterpretation of some photos. in anycase I think I have a workable understanding of some variations of this device now, though im still confused by others. – reciprocalmotionenjoyer Mar 06 '22 at 21:30
  • @Graphus its with a heavy heart I admit you're probably right. the only real downside is the lack of speed control that most drills tend to have. – reciprocalmotionenjoyer Mar 06 '22 at 21:35
  • @reciprocalmotionenjoyer, you could probably do a surprising amount with a fixed-speed drill, if it's what you already have I'd certainly suggest building the headstock around it and having a go because it will at least allow you to dip your toe in the water of turning. But, here at least, it seems that even some of the cheapest corded power drills (~$25) have trigger-based speed control with the dial on the trigger to preset the locked-on speed! If there's no equivalent there you could haunt Craigslist or similar, drills are by all accounts the most abundant of secondhand tools. – Graphus Mar 07 '22 at 13:27
  • I think this old stack woodworking article may have what you're looking for, including some additional photos and links to some reference books. https://woodworking.stackexchange.com/questions/3978/what-is-this-turning-process-on-the-woodworking-wikipedia-page – Eric Anderson Mar 19 '22 at 19:42
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    For mains-powered drills (also @Graphus, who may have come across these before) it's possible to use an external speed controller and a fixed speed drill. This is the same as a dimmer switch for incandescent lighting, though slightly heavier duty. If making a drill-powered lathe I'd build one of those into it somewhere, and also fit a suitably-rated footswitch (I've got the latter for my drill press that takes a normal drill - and has the dial/lock combination Graphus mentions) – Chris H Apr 27 '22 at 13:37

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In the video, it looks like one center is fixed (headstock) and the other center is adjustable (tailstock). I would guess there's some friction in the tailstock (it probably has a tenon that fits snugly in the slot), but the turner appears to be also holding it in position with his left foot. There shouldn't be much force on the tailstock, so he probably doesn't need to do much with his foot.

I'm sure some people use wedges to hold the centers securely rather than having yet another thing to tend to. On my pole late my "poppets" (tailstock and headstock) have tenons that descend beneath the bed. A mortise runs through them under the bed, and a wedge can be hammered in to pull the poppet tight against the bed. You can find many pictures online, such as https://www.reddit.com/r/turning/comments/coaqga/i_reworked_the_poppets_on_my_pole_lathe_details/.

For this lathe though, that would mean raising the lathe up off the floor a bit, which would make it harder to operate with your feet. I think your last picture shows the solution, which is that the bed runs through the tailstock, and so those wedges pull the bottom of the tailstock mortise up against the bed, providing friction.

schmmd
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  • +1 Thanks for the valuable insights. Did you read through the Comments? I tried to steer the OP against this idea towards something more practical (and SO much easier in terms of body mechanics!) if the goal is actually the turned items, rather than mainly or entirely to investigate the technology. – Graphus Apr 11 '22 at 18:50
  • It would be nice of you to [edit] your answer to include a couple of pics of your lathe (overview and details) to make it easier for everyone. – FreeMan Apr 12 '22 at 15:53
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    a few weeks after originally posting this I acquired a pair of metal-lathe steadyrests which were being thrown away, which i simply bolt through the dog holes on my bench, one holding a live-center and the other a drill with a drive spur in it.
    I initially tried this with a second live center (also saved from the dumpster) and a bow, and @Graphus has a point, motors are pretty useful things.     – reciprocalmotionenjoyer Apr 28 '22 at 21:37