The Super 'Fonly

A screw cutting, metal turning lathe built from wood


WARNING!
In today's litigious times, I feel I must make it clear that building or operating machine tools or other power equipment carries inherent hazards.  While proper safety equipment, good technique, and simple sense can go far to reduce the risk, nothing you can do is risk free.  The number of carpenters, machinists, mechanics, and others who work with power tools and equipment, my age and older, who are missing one or more fingers or a larger limb is sobering.  If you choose to follow in my steps and construct you own machine tools, or even if you buy commercially made tools, always remember that the tool will not watch out for you -- only you can do that.  The cautions for working around power tools have been published thousands of times -- I won't repeat them, except to say that tool parts can be repaired or replaced if they break.  The same can't generally be said for your fingers or your eyes.

Bottom line here: I can't be responsible for your actions.  If you buy a tool or make a tool, even one identical to the ones I describe here, and it bites you, it's your own fault.  If you can't be bothered to learn how to use tools safely, or can't hold yourself responsible for the consequences of your use of a tool, maybe you'd best stick to video games.  At least in a game, if you die, you get to try again.

If you haven't read the two part article about the 'Fonly Lathe, I'd recommend you do so now -- I'll wait.  There are a lot of important concepts in that article, relevant to the construction of the Super 'Fonly.  Most important, to my mind, is that a metal cutting lathe doesn't have to be made of cast iron, or even cast aluminum (like a Gingery) -- or even steel or aluminum tube.  For a small lathe like the 'Fonly, or even up to the 6" x 8" size of the Super Fonly, hardwood ply such as Baltic Birch, Appleply, maple, oak, or even birch ply is plenty stiff and strong.

A word about lathe sizes, in case someone is reading this who isn't already a machine tool enthusiast.  Lathe sizes are given by two numbers -- a common imported lathe sold by several companies in this country is called a 7x10.  The first number is the swing, the largest diameter of work that can be turned.  This is typically given as the swing over the bed, however, and the useful size is more limited by the swing over the carriage, which is usually smaller by a couple inches, sometimes more.  This is the diameter, also -- that means that a seven inch swing lathe has the center only three and a half inches above the bed, and such a lathe might well be able to turn only three inch diameter work over the carriage.  The second number is the length between centers.  For the above example, that's ten inches -- the bed is always longer than this; the tailstock, which holds one of the centers, sits on the bed (or, correctly, on the ways, but they're usually part of the bed) and takes up several inches, and in many more or less conventional lathe designs, the headstock also sits on the ways.  For instance, the 7x10 has a bed casting that's more than eighteen inches long, with the headstock and tailstock taking up some eight inches of that length.

I propose to home build a 6x8 lathe, mostly from wood.  I want to be able to turn four inch work over the carriage, meaning up to four inches diameter over the full eight inch length.  Given a carriage height above the ways of about an inch, that means I need to put the centers about three inches above the ways.  The original 'Fonly can turn work up to about two inches diameter, and because it doesn't use a conventional carriage, loses little on full length (about three inches) work compared to short maximum diameter parts.  The center is just over an inch from the ways, but here the limitation isn't the strength of the wood used to clamp the rotary tool; it's the rotary tool itself, designed to turn small bits at very high speeds.

The Super 'Fonly starts with a different kind of power, and can take full advantage of the strength of hardwood.  I'll be using birch plywood (a quarter sheet cost me $15, new, from a chain retailer, and contains enough wood to make at least two of these lathes), some rock maple (which I'll get at a hobby shop -- Radio Control fliers use the stuff in convenient precut sizes to mount their engines), an assortment of small bolts and nuts, and a piece of steel plate for the ways.  There'll probably also be some brass parts and assorted knobs, springs, and doodads as I go along.  So far, as of October 21, 2001, I've got the motor (a defunct sewing machine with a good motor cost $10 at a local thrift store) and the quarter sheet of 3/4" birch ply.  I've also ordered several sets of plastic gears that I'll be using later, for around $15.  I'll be updating this page as I progress.

November 3, 2001

I've got the baseplate cut, have received the plastic gears, and have the motor detached from the sewing machine, along with the handwheel, pulley and belt that transmitted the motor's power to the sewing machine mechanism.  I even have some pictures!  Just click on the thumbnails you see here to get more information and a larger picture.
 
 

Since these photos were shot, I've routed a decorative edge around the baseplate and cut the two strips of plywood that will raise the ways plate up off the base, allowing the carriage to grip over the edge of the ways plate and providing working space for the lead screw and the associated items on the apron.

November 10, 2001

I got a piece of 3/8" x 3/4" maple 18" long, and cut that up into 1 1/2" pieces; each of those pieces will bridge across a headstock section made from two laminated layers of the 3/4" birch plywood, allowing a single bolt to bear on both layers without tending to split them along the glue joint.  This, in turn, will allow enough tension in the bolts that fix the headstock uprights to the base board to give good stiffness.  The stiffness will also strongly depend on the flatness of the bottoms of these uprights -- if they're rockered or irregular, the upright will tend to tip.  I'm working on ways to ensure the bottoms are flat and perpendicular to the faces; the best idea I've had so far (that fits with the tools I have available) is to cut the pieces slightly over size and resaw them on my bandsaw after lamination, with the table and miter gage carefully calibrated to give exactly square cuts.  I've had only so-so results trying to sand pieces to precise angles on my power belt-disc sander; the relatively cheap machine doesn't have very good control or calibration of the angle of the table to the disc or belt, and the belt tends to sand things convex in any case because of the slight looseness required for the belt to run smoothly over the platen.

November 19, 2001

I picked up the ways plate and spindle blank that I'd ordered from Online Metals -- a two foot length of 1/4" x 3" 1018 cold finish plate and a one foot length of A513 Type 5 DOM (Drawn Over Mandrel) tube, .750" O.D. and .510" I.D., cost just under $13 when picked up from their will call here in Seattle.  I might have paid less for these parts from a scrap dealer, but this way I know what they are.  Both parts are over length, and will be cut down to length as the project progresses (the spindle likely after installation, using a tool in the tool holder or a temporary tool holder).

November 23, 2001

On a tip from someone on the Yahoo! e-group for Gingery Machines, I checked at Hardwick's, a local old-style hardware store, and found the 3-step sheaves I need to carry power from the countershaft (which in turn is belt driven by the motor through the reduction pulleys original to the sewing machine that supplied the motor) to the spindle.  One sheave is used, and needs a little clean up, but it only cost $2.75 and fits the 3/4" O.D. of the spindle, which can't be said for any 3-step sheave I found in extensive Internet searches; it also has a very slight bend in the end plate of the smallest sheave, but I think I can straighten that without too much effort.  The other sheave is brand new, and was only $6.50, with a 1/2" shaft hole; that fixes the size of the countershaft for me, since I'll have to bush the sewing machine handwheel pulley in any case (it's got a bore around 1" I.D.).  I also picked up (at Lowe's) eight 1/4" x 20, 2.5 inch long flathead machine screws to fasten the ways and bed to the baseplate, along with nuts to fit them that will be crushed into the baseplate to provide what amounts to a threaded insert in the wood.  The screw heads will be countersunk in the ways, so as to provide a smooth, flat (at least after scraping) top surface for the ways plate.  Finally, I got a six foot length of 1/4" x 20 threaded rod -- the store was out of the three foot lengths, but I figure this size will give me the four studs I'll need to fasten the headstock to the baseplate and still leave more than enough to make the English lead screw -- the total for the screws, nuts, and threaded rod was about $5.

January 1, 2002

I've been a little tardy with updates, because while I was acquiring bits and pieces, I wasn't getting anything actually done on the lathe.  Since the last update (over a month ago) I've gotten the bearings for both spindle and countershaft, and the shafting for the countershaft.  I ordered these parts from MSC Industrial Supply online, and got them in two working days from their shipping center in Reno, NV.  I paid a little more for shipping than I'd expected, but the total order (four bearings in two sizes, and a foot of 1/2" shafting) was still only about $21 inclusive.

I've also picked up a piece of laminated red oak, 1 1/2" square by a couple feet long, that will be used in the new version of the headstock caps; the oak stock cost about $6, and I'll be using about half of it: two 3" long pieces of the oak laid across the top of each laminated plywood headstock base; the bearing bore will go along the join between the two pieces, and they'll be clamped by the same studs that hold the headstock risers onto the base plate.  This will let me easily replace the bearings if I find the oilite parts I ordered don't work as well as I expected, or if plain wear or a need for a larger spindle should rear their heads.  I have enough dimensions in place to determine the length of the bed and ways at 16" exactly, and got the bed riser pieces cut to length.  That allows a half inch or so of clearance at the tailstock end for the lead screw hand wheel (which will have a removable crank knob to accomodate the cover this lathe will eventually get), and about three quarters inch at the headstock end for the change gears and spindle tensioning nut, again allowing clearance for a cover.  Given a reasonable figure for the dimensions of the tailstock and centers, I'll have between 10" and 12" available between centers, which is longer than I originally expected -- better than shorter, since one can always move the tailstock up to turn shorter work, but it's hard to move it back beyond the tail end of the ways when the work is too long.

There'll be about 1/8" on either side of the spindle sheave, which will be locked to the spindle by setscrews on flats filed in the spindle.  A relatively large (about 4" x 12") dead area in the right rear of the 9" x 24"  base plate will probably become a resting place for things like tool holders, steady rests, etc. when not in use.  Here are a couple pictures of the base plate with the lumber, before and after cutting the bed risers and headstock caps.  The headstock caps don't look high enough here because they don't have the plywood sections under them yet, and the bed risers are a little hard to see against the baseplate due to low contrast -- they'll look much better when they have the steel ways plate on top.
 
 

January 13, 2002

I got the rest of the wood headstock parts cut today.  These are the plywood pieces that will be laminated to go under the oak caps; essentially, these serve no function other than to act like, well, blocks of wood to support the caps which in turn support and locate the spindle.  They'll be held in place by 1/4" x 20 tpi threaded rod, fixed in a nut crushed into the baseplate at the bottom and clamped down by a nut or wingnut at the top.  Careful reaming/boring of the spindle holes and simple shims will adjust the amount of clamping force on the oilite spindle bearings when the wood is fully compressed.  Use of very tight bolts will also transfer side and torque loads from the spindle into the baseplate, which will be stiffened by firm compression against the headstock pieces and the bed risers.

Question: how do you drill a 1/4" diameter hole, 3 1/2" deep, endwise through a block without having the hole wander?  Answer: with a router.  Now, I don't mean you chuck the 1/4" drill bit in a router and somehow use it to drill the hole -- I mean you laminate the block from two pieces, and use the router to cut grooves that will form the hole before you glue the laminations.  Since the hole in this case wants to be clearance on the threaded rod, it doesn't need to be exceptionally precise, and I was able to use my Dremel router table accessory and a 1/4" straight router bit, cutting against the fence, to route 1/4" wide, 1/8" deep gooves in each piece.  The grooves will match up when the plywood parts are glued together to form the through hole, and the holes in the oak caps can be drilled to match -- since the oak is only 1 1/2" thick, I can drill those with my drill press and a regular 1/4" drill bit.

Here are a couple images of the headstock parts, one showing the routed grooves and the other showing how the plywood parts will match up to the oak headstock caps.
 

April 21, 2002

That wood has been sitting there for a long time -- I've been rather short of money, and I've had a minimum of free time on top of that.  This weekend, however, I did make some more progress; I got the headstock bases and lower caps glued up.  After looking at them in the assembled state, I've decided a little more stiffness is in order, so I'll be adding some more wood to the headstock, joining the two uprights together below the clearance for the sheave and putting a "floor plate" between the joining rails.  All of this will be inboard of the uprights, so as to not interfere with the countershaft.  The final headstock assembly will then be glued to the base plate, as well as held with the 1/4" x 20 studs I had originally intended -- should be hell for stout, as it will need to be if I ever put enough power on this lathe to let it make the cuts it'll have the clearance to take.

In any case, prior to gluing up the plywood parts, I sanded them on my power sander, using the miter gage to make all the edges smooth and square.  In the process of gluing up the risers, I found (not very surprisingly, given that I made them with the parts separate) that the grooves in the plywood parts and the holes in the caps didn't line up very well.  Well, every problem has one or more solutions, and if you look, there's often a reasonably cheap one within reach.  In this case, I bought three feet of 1/4" diameter music wire (essentially drill rod, but made from cheaper steel and work hardened in drawing).  I cut off two pieces with my Dremel and a reinforced cutoff wheel, and ground (well, sanded) both ends square and flat on my disk sander (again using the miter gage for accuracy).  I then used a hammer to drive these rods, with their freshly ground ends cutting as they went, through the holes in the risers.  In the process, they cleaned the holes up so that the threaded rod that will become the studs should go through pretty easily; they also served as nice alignment pins for ensuring that the lower cap pieces were lined up with the routed grooves in the plywood parts.

Over the next weekend or two I should be able to get the rest of the headstock parts cut, the oak caps sanded down to the dimensions of the plywood parts, edges rounded where they'll want to be rounded, and the headstock installed onto the base plate (assuming my wife doesn't find too many more projects for me around the house).  Then it'll be time to cut the ways to length and start on dovetailing the ways, installing and flattening it.

No pictures this time -- nothing really new to see, but next update you'll get to see the completed headstock, ready to drill for the spindle, I hope.

May 5, 2002

Well, I didnt lie; the headstock is assembled and ready to mount on the base plate, drill, and line bore.  There are other steps I need to complete before I'm ready for those operations, but the headstock is ready.

Yesterday and today, I finished cutting the last parts, sanding everything to matching size, and gluing up the headstock parts.  Here are the pictures:
Headstock parts, ready for gluing up.

As I mentioned in an earlier update, I decided to reinforce the risers, since I doubted the 1/4" x 20 tpi studs that will anchor the risers to the base plate would be stiff enough.  In the first image above (which, like all the images on this page, is a link to a more detailed page and larger image), you can see the reinforcement plates and risers rabbetted to fit together.  In the second image, you can see the complete headstock after gluing up, final sanding, and rounding all external edges.  The third image is a detail of the oak pillow blocks.

The next step from here is to locate the headstock attachment point on the base plate, and mount a block that will be a snug fit in the open center of the headstock.  That block will both act as an additional stiffener, and serve to positively locate the headstock, allowing (if necessary) removal (for repairs, upgrades, whatever) and a return to the same location and alignment.  This is necessary since my headstock, unlike that of the Gingery and most other lathes, doesn't ride on the ways; rather, it's fixed in place on the base plate.


Motor, handwheel pulley, and belt: from a dead sewing machine, $10
1/4 sheet birch plywood, new, $15
Plastic gears, four sets, surplus: $15
Ways plate and spindle blank, new: $13
Step sheaves for spindle drive, one new, one used: $10
Ways bolts and threaded rod, new: $5
Shafting and bearings for spindle and countershaft (including shipping): $21
Oak headstock caps: $6
1/4" music wire for alignment pins/reamers: $3

Running total: $98

Return to Homebuilt Lathes
Return to my home page

All material on this page and pages linked from this page within my web site is Copyright © 2001, 2002 by Donald Qualls
External links are copyrighted by their creators; links from here do not imply ownership of that material.
If you have comments or suggestions, email me at silent1@ix.netcom.com