Spring Pole lathe, broken!

When you build your own tools from scratch, you know what is needed to fix them.  Normally this is not a concern but perhaps due to boneheaded operator error (or boneheaded builder error, or both) might be necessary at some time in the distant future.  In my case, it was the near future, and I broke one of the spring poles, the upper one.  And the wire connecting the spring pole to the upper arm.  At least my digits are all intact and my boneheadedness required no stops to the ER.  Is boneheadedness even a word?

A week or so after getting home with my completed lathe, I was merrily treadling away and thought “I need more spring pole!” so I moved the metal ring more to the left, which alters the fulcrum for the spring pole.  This effectively changes where the spring pole bends, thus shortening the spring and making the action snappy.  At the same time I also changed where the spring pole attaches to the upper, over-head arm, again shortening the throw which should make the action snappy as well.

It made it snappy alright.  Treadle treadle treadle snap!  The treadle went all the way to the floor and stayed there.  Because of my experiences with the parachute cord, that was my first suspect (the knots tended to come loose and I’d re-tied them four or five times already).  Nope, those are all tight.  I look over at the spring pole and it was hanging at an ugly angle.  I felt shame.  “Pittsboro, we have a problem”.  Well, crap now what?  I decide to get MacGyver on it and try moving the fulcrum point on both the arm and spring pole.  This resulted in action akin to ‘overcooked linguine’, but I could still do some turning.  That is until I manage to break the wire that connects the spring pole and the upper arm.  When we wrapped these, Roy suggest we put a pretty good bend right where we wanted the loop to start/stop, then wrap any excess below that.  I got a bit overenthusiastic with this bend and created a weak spot for the wire, which caused it to snap under stress.  “She can’t take no more Captain!”.

The first chance I get I go out in the woods, find a young sapling, take my bow saw to the base and cut it down. “We can rebuild it.  We have the technology.”  I think it is a beech but it might be a birch.  Meh, it’s a late summer pole (heh heh) and if it breaks again, I can just go get another one.  I have 5 acres of the stuff surrounding me.  So I cut it to length, grab my new-to-me drawknife and take off all the bark.  Then I get one end down to the requisite diameter using my spokeshave and leave the other end on the thicker side, thinking a little extra diameter there will help should I get all springy obsessed again.  Of course that means widening that opening and also finding a bigger ring to go around the two poles.

I probably should get a turning saw, because sometimes you just need a turning saw. I ended up widening the opening for the new spring pole with some chisel work and slightly scary forstner-bit-in-the-shop-smith action.  Remember, no ER visits.  I had to break out the rasps and clean up my chisel work. Yeah, a turning saw sure would have been nice.  I positioned this photo to hide my beaver-esque chisel work.

For the wire, I bought 100′ of the stuff at the local hardware store, but also remembered Roy saying you want this connection to be as stiff and non-elastic as possible–he suggested one good solution would be a piece of wood connecting the upper arm with the spring pole.  So I got a hardwood dowel, some eye screws and connected the two parts that way.  I need to adjust the dowel (I cut it a bit too long) but overall I’m pleased with the results.  While doing all this I took the axle out of the upright, and put some grease on it.  The entire lathe really works great now, so with a few more improvements (tool rest tightening, tool rest shimming) the lathe ought to be turning out table legs and tool handles for a while.  I did find that the wood had swollen a little since I’ve left it outside, so getting the ways and stretcher back together after breaking it down proved to be a bit more trouble than originally.

Poor lathe needs some Viagra now that its heart is healthy enough for treadling.  “If you treadle for more than 4 hours without stopping for water, you might get dehydrated and keel over.  Please also eat once in a while or you will get light-headed and perhaps keel over.  Never treadle in front of your door or you will track in wood chips.  Women who are pregnant or may become pregnant or have been pregnant or breathe air tend to take a dim view of wood chips tracked into the house, which (you guessed it) might result in you keeling over.”

I’m just going to leave it unfinished and let the pine age naturally.  Erhmm, gracefully.  And yes, in case you hadn’t noticed, I tend to use quotes from popular media (TV, Movies, Music).  Maybe I should read more.  Well, let me restate that.  Maybe I should read classic literature more, I read a ton already.  No, seriously, I need to make some bookshelves to hold all my reading material.  Hmm, Jefferson “Library of Congress” bookshelves?  From PW a year or two ago?  Maybe, but sometimes you just need a turning saw…

Update. The screws pulled out of both ends of the dowel (on two different occasions), so that solution might not be worth the trouble. I might have made the pilot holes a little too big, but since I have 100 feet of the galvanized wire, I just used that and got back to work.

Woodwright’s School, Spring Pole Lathe, Class photos

Here are some photos of my classmates working away in the Woodwright’s school.  Ed Lebetkin, who runs the tool shop upstairs, commented that he wondered if Roy did any instruction or not in this class, as we always seemed to be busy bees going about our work w/o a lot of direct involvement from Roy.  While not true (Roy showed us a lot), it is true that from what I could tell, all of us were fairly experienced woodworkers who didn’t need a lot of intense direction.  Some were faster than others, but overall everyone finished their lathe, all within an hour or two of each other over the course of a week’s work.  Fun group and I know I’ll keep in touch with a few of them in the future and hope to run into them all at some point at woodworking events or classes.  Some of us might show up in the local county travel video (they came through one afternoon while we were working away).

At the end of the day on Thursday, with our lathes looking pretty lathe-like, we decided to get some glamor shots and put them all up on our workbenches.

Left to right, Cameron, a timber framer from Canada, Terry, Brandon (behind the upright), Dan, Gerald from Texas, and Chuck also originally from Texas but now making Windsor Chairs in West Virginia.  I might take a chair class with Chuck next summer, which would be fun.  We stayed at the same B&B so got to chat quite a bit over breakfast, along with another classmate Larry.

J.T. the youngest member of the class.  He and his wife were moving west after this class to go to grad school, J.T. in architecture if I recall correctly.  He had also taken the Woodcraft Week earlier in the summer, and had the adze scar to prove it (yikes). We were all invited out to Roy’s house after Thursday’s class and during the tour, JT found the adze that bit him.

Terry, working on the bench in front of me.

Larry behind me, working on the tool rest I believe.  I also got to know Larry pretty well since he also stayed in the same B&B.

Here Gerald is using the moving filister to cut the rabbet in the tool rest.

I usually try to get photos of everyone, and I think I did for this class, some show up in previous installments of the class.  From the bench layout,  front to back, right to left when looking out towards the street, Cameron, Terry, Joe (me), Larry, Brandon.  Then Curtis, Chuck, JT, Gerald, and Dan. Dan had the catbird seat for a quick run upstairs to the tool shop.  In the photo below though, left to right, JT, Chuck, Curtis, Roy, Dan, and a visitor to the shop.

I had a great time in Pittsboro, and despite it being a small town, there are some good restaurants with nice people everywhere.  I’m glad I stayed in the B&B near the school, but JT and his wife stayed at the one a little further away (2 extra ‘blocks’) and said it was nice, and Cameron and his wife and son stayed at one on the way out to Siler City, which Roy hadn’t heard about yet.  Cam said the hostess literally stuffed them with food every morning.  I know I’ll take another class here, maybe the Woodcraft Week which is held out at Roy’s property.  Other than the bar behind Roy’s school though, I didn’t find any live music that didn’t require driving.  I wanted banjos (darn it)!

Spring Pole Lathe, completed.

After getting the majority of the lathe together in the first three days, the last couple were about finishing the tailstock/puppet, making the toolrest, treadle arm, axle, spring poles, and setting the dead centers. Most of this work was less strenuous but required a lot of precise work to get correct. Plus we got to pedal a metal lathe! That was fun.

Here I am turning the axle for the upper arm.

We started with some round stock, hack sawed it to length, then got on the Barnes 4 1/2 metal lathe that Roy has and pedaled away.  I watched most of the other students do this first and the biggest trouble most people had was pedaling backwards–it is a direct drive so the direction you pedal is the direction the piece turns.  As with wood turning, you want the piece turning towards the cutter.  There are two controls which determine where the cutter is in relation to the piece in two different axis.  Not being a machinist, excuse my terminology if I get it wrong.  One controls the feed rate along the axis of the bed, that is towards the headstock or away from it, and the other controls the feed rate at some angle to the bed.  In the photo above, you can see part of mechanism is angled at maybe 15deg, so that moves the cutter from the center of the round stock to the outside.  Basically this entire operation is to put a bit of a crown on the axle and make it more polished from the hacksaw. If you were doing this at home w/o a metal lathe, you could use some metal files to de-burr the stock and probably call it a day.  But Roy has one and it was fun to use.  And hey, a picture on my blog with me in it!  Ha, that is rare as I am always taking pictures of everyone else.  Thanks Chuck for doing the honors.

Here is the Barnes 4 1/2 sans operator.  If I ever get into metal work, I think having one of these would be a hoot, though an electric powered lathe might be cheaper (not sure what these go for).

The tailstock/puppet came from one big piece of pine, and after flattening and thicknessing, then cutting the long tenon that would ride between the bedways, I needed to mark out the mortise for the wedge which will hold the puppet tight to the ways.  But first I needed to cut the wedge to use that for marking out the slope on the mortise.  You want the wedge to be pretty long so that it is easy reach over the bed and whack it tighter and yet there is enough meat on the near side to be able to reach and whack it loose.  My wedge ended up being 10″ long, 1″ at the near portion and 1 3/8″ at the far end.  You want the flat end to face up so that it pulls the puppet tight evenly.  Using the wedge to mark out the mortise makes things easier.

I went a bit overboard in making the mortise extend up past the bed ways–the darker marks are where the puppet runs into the bedways.  It doesn’t matter though, just so long as there enough clearance to make the wedge good an tight.

And the wedge.  Exciting.  Yes, it does say ‘Joe’s Wedge’, just in case I dropped it in class.  I also have some directions on it–“Up” so I don’t get confused when using it.

The spring poles started as two pieces of ash, about 1″ square (sorry I forgot to measure the starting dimension).  The first step was to shape them to a rough octagon.  I used my new wooden jack plane from Ed’s toolshop for this.  Man, ash planes nice.  Roy gave us an easy way to lay out the octagon–using a 24″ square (a ruler would work just as well), place the end at one edge of the square side and the other edge at the 24″ mark, then at 7″ and 17″ make a few tick marks.  Those become your guidelines.  Grab a compass with a sharp pencil, and using the tick marks, set the compass.  Run it down the length and do the same on the other side of that face.  Repeat for all four faces.  Once we had the octogon, the drawknife came out to do some initial shaping.  Never having used a drawknife before, Roy gave me a quick lesson after seeing my rather herky-jerky technique.  As with many things in woodworking, describing it is tougher than seeing the actual motion in person (which is why taking classes for an amateur like me is so important), but basically the drawknife I was using is meant to be used bevel side down.  Then with a slight skew to the blade, you draw it towards you as simultaneously moving from left to right or right to left (which ever feels most comfortable).  This gives a skew cut and the shaving curls off the pole.  We didn’t have any shave horses, so this was all done with the piece in the face vise. Once basically round, the next operation involved making the ends fit the two holes for the lower spring pole and the one for the upper spring pole.  I used a metal spokeshave for this, as well as a piece of scrap with the same diameter hole bored in it for testing fitment.

The dead centers we used are 1MT (morse taper) centers, precision ground.  As Roy explained, any wood turner from the ‘old country’ would like have brought a few very important metal bits with him, and the dead centers are one of them.  Most modern lathes have their centers with sockets also precision sized for specific morse taper sizes (2MT being fairly common from what I’ve seen), and if I was making this lathe again, I might consider using that for the centers.  On our lathes, Cameron and Brandon helped figure out the precise auger bits we’d need for this operation.

First you find center between your bedways, then decide on the height for the turning.  Each lathe might be a little different in these dimensions, so there was no fixed measurement.  The fixed puppet/headstock got bored first, and if I recall correctly, it a #7 auger bit followed by a #6.  You drill the wider, outer portion first, then the narrower portion.  Then using a reaming bit, you connect the two until the center fits snug with no gap.  For the headstock you get to ride the bedway like a horse (yes, it easily held me and I am no small mammal), and with a spotter or two to be sure you are level, start boring away.  Once fitted, the center in the headstock is used to mark the tailstock–but, you want to be sure it is in ‘turning mode’ and so you get it right up the headstock, with the base of the tailstock just a smidge towards the headstock, then fit and tighten the wedge.  The wedge will bring the tailstock vertical and should leave a nice mark where the center needs to be.   Due to the thickness of the tailstock you have the option of not boring all the way through, but I figured I  might want to knock out the center at some point in the future.  My centers are just a wee bit off without the wedge in position as you see in the next photos, but almost dead on with the wedge fitted.

Once that is done, there is just a few more things to finish up before we were out on the sidewalk in front of Roy’s school, treadling away.  The arm that attaches to the spring pole and the work piece should be made from a light piece of wood, in our case just some white pine.  The bearing for the axle does have to be fitted precisely as well as the holes for the axle in the upright.  I think we used some stainless tubing for the bearing, which Roy had smoothed on the ends using the Barnes metal lathe, and which has a tight fit with the axle rod.  For boring the holes, we marked the centers on both parts of the split upright in both dimensions, then with a pair of spotters bored these holes.  In order to get the upright in the correct position, you need a few scraps under neath for support as you don’t want this shifting while boring.  Other than the dead center positioning, this is the most precise part of the woodworking.

The toolrest was a pretty easy affair, with a rabbet for a metal wear strip, a notch for the base, the base itself, and finally the holding mechanism for the toolrest.  I made the mistake of shaping the top of the tool rest before I cut the rabbet, but it didn’t seem to affect it much.  My biggest mistake was not making sure the toolrest was the same width end-for-end.  The right side is just a little lower than the left and when I measure the distance I needed for the notch to match the rest with the centers, I used the left side.  I need to go back and shim the notch a little to bring the right side level.  Overall I am not very happy with this tool rest as it is hard to tighten with the wingnut, and even when I get it as tight as I can, in operation, it will move some on me.  I think I need to make a new block between the tool rest and the base which rides under the bedways.  And find a better way to tighten it, either by making a wingnut extender or a completely different mechanism.  Maybe a cam clamp, which would be quick to move.

It might not be obvious in the next photo but you can probably see the toolrest on the right is below center.

The hole through the center block needs to be fairly straight, and the length of this block needs to be precise.  I think I got a few of these variables wrong and thus my dissatisfaction with the holding ability of this tool rest. That and the blasted wingnut which digs into your fingers.

We just used some woodscrews to attach the upright part of the toolrest to the middle portion.

The metal is just some flat stock, into which we bored holes for the wood screws.  We also took the time to countersink the heads so they fit fairly flush, that way they don’t accidentally mar any piece you are turning if the tool rest is quite close to the turned piece.  Of course, Roy had a hand cranked drill press for this.  A bit of 3-in-1 oil for lubrication, a sharp drill bit and some chicken-fried salad power is all you need.  Yes, they really do fry everything in the South.

For the foot treadle we just used a piece of pine cut.  The drive cord is leather, but we didn’t have enough for the entire class so the ends are parachute cord (which actually kind of sucks).  Future mod is to change to full leather drive cord and possibly change the foot treadle as well.  It takes some getting used to and I find I have to adjust my stance or the cord or the treadle more often than I am actually turning.  The spring pole and upper arm are connected with some galvanized wire.

Here is the drive cord if you are looking to make a lathe.

I’m not sure why one says 1/4 and the other says 5/16.  Roy had two rolls, so they must have been different diameters.  I’ll have to pull out my micrometer and check to see which one I ended up using.  This is important stuff, and it needs to be ultra-precise.  Well, ok, it really doesn’t need to be precise.

And back at home, ready to turn some wood.  Turning right in front of the front-door is not the best idea in the world though.  Wood chip tracks…but being able to turn on the porch in a nice, late summer day sure makes it worth the clean-up.  Plus I can just sweep the chips off into the flower bed for some instant mulch.

And my first practice piece, some sassafrass from the wood pile.  Yes, I need more practice.

I’ll have a couple follow-up posts on this lathe as I have already broken a few things.  🙂