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How short should I make the bed of my lathe?

W

wilburpan

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Sep 21, 2008
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I recently bought a used Conover lathe. For those of you who aren't familiar with this lathe, it has a wooden bed. This particular lathe is made of microlaminated plywood built up to make a pair of beams 10 feet long, effectively giving this lathe a capacity of 7 feet between centers.

I got it home, and found that I have a slight issue. The lathe is too long for my shop. Of course, this is a good problem to have, and honestly, I suspected that I would have to do this, but it looks like I'll have to shorten the bed, which is easy, of course, since it's made of wood.

So my question is, coming from someone whose longest spindle piece so far has been a tool handle, how much capacity should I reserve for myself? I've got a few notions kicking around:

1. 42", because that's what most 16" swing lathes (Jet, Oneway) seem to have as their between centers capacity.

2. 54", because that seems to be the longest capacity between centers for any lathe being made today without the use of bed extensions. (Robust Sweet 16 and Vicmarc VL 300 long bed, in case you were wondering.)

3. Shorten it just enough to put it in the spot that I have for it, which would give me about 5 feet between centers.

4. Keep the bed as is, and rearrange all the other stuff in my shop to make it fit.

I'm leaning towards option 3, but one thing I don't have a good handle on is if the capacity over 40" is going to be wasted. Looking at the things around my house, it seems that most of the turned spindles, like table legs, stair railings, etc., are at most about 3 feet long. Over that length, the only thing I can think of that would require turning would be the corners of a four-poster bed, which jumps straight to 6+ feet. In other words, I'm not sure how often I would need to turn something between 3 feet and 6 feet long, in which case I might as well chop the bed down to give me 42" between centers. If I made the lathe that short, I could make use of the extra space that it gives me.

I guess another way of asking this question is: how often do you turn an object between 36" and 84" (7 feet) in length?

Of course, what's going to happen is that 10 minutes after I cut down the bed of this lathe, my wife is going to want a four-poster bed, even though she's on record as highly disliking that style of bed.
 
How about making the cutoff part into a bolt-on bed extension, you might need it once or twice or hopefully more. When the time comes for that big paying job making a fancy 4-poster bed, you might not mind rearranging the shop just to use it. Use it for a workbench when it's not a lathe bed extension ;-)
 
I would go with option 4, at least at first. If a year or two went by and I didn't find some use for the exta capacity and I really needed the space I would break out the saw and shorten it up.

I just turned some pedestals with the tallest one being 48". Not something I ever expected to do, but I was able to because I had a bed extension for my lathe. I have an idea for a 6' hollow form that I would like to turn, but I don't have the capacity right now.

Ed
 
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Another vote for option 4. Rather than cut some off, you might clamp some plywood to the unused 4 ft. or so of the bed and use it for a work table, grinder stand area, etc. I like Ken's idea too. Presumably the cut off portion/table would still have to be somewhere in the shop, but perhaps more conveniently located than at the end of the lathe. If making a bolt-on extension, you might want to make and install all the (steel?) connection brackets first to establish alignment. Then remove brackets and make the cut. Good luck with your project.
 
If you can make room, why not? Mount your grinding operation on the unused end , and your tool holder inside that. Make sure they're mounted well.

If you have to choose, 40 is a good choice. Very few tables require more than a 36" leg, and you can always build longer components from tenoned shorter pieces. I don't have six or seven feet to spare, so that's what I'd do.
 
Lathe Advice

IIRC, balusters, or stair railing spindles are typically manufactured at 42" to give enough room to cut them down. Many newel posts are 54". As far as bedposts go, a lot of them were made in two pieces, joined with a mortise and tenon that could be glued, or not glued for dismantling purposes.

I liked MM's suggestion of mounting your grinding station on the end of the ways. That would keep it handy and free up some space elsewhere.

Kurt🙂
 
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I agree with MM. Option 4 preserves all the other options when/if your choices are better defined, which they don't seem to be at the moment.

Joe
 
I would go for whatever allows the longest bed. I have a Vic 300 long bed, and while the need to turn a spindle that length the extra length is very handy. I use the tailstock quite a bit when roughing bowls or shaping some of my off center pieces. When not needed, I simply move it to the end of the bed. The tailstock is pretty heavy and I wouldn't like to have to handle that twice for each bowl.

The long bed also follows along the old hotrodding axiom, "If one's good, two's better"....

Fog
 
you could make you shorter rails and put the long ones up, if you needed longer you could change them out. but I would keep it as long as it is.
 
Thanks for the input. I wound up cutting the bed of the lathe down, and thought I'd share some pictures. I could have rearranged the workshop to put the lathe in as is, but it would have made everything else suboptimal, including the location of the lathe. The bed is now 8 feet long, and gives me about 54" between centers.

I think that funniest part about getting the lathe into my shop is that for such a big long lathe, I wound up using hand tools to cut down the lathe bed. I used a Japanese saw to cut the ends of the beams down, and a bit and brace to drill new holes for the bolts to hold the bed onto the legs.

The headstock is surprisingly heavy. From what I understand, the design of this headstock was derived from a metal lathe. If you look closely at the picture, you can see where I made some more cuts to tweak the lathe. Originally, the part of the beam that the headstock is against was about 1/4" longer, which put the four step pulleys out of alignment by the width of a pulley. I cut this back so that the pulleys are in much better alignment, again with a Japanese saw by hand.

The current speed setup is a four step pulley on the headstock, connected to a four step pulley on a short jackshaft, which has two step pulleys connected to the motor, giving me 8 speeds as it stands. I have no idea what those speeds are, though. I plan on switching to a VFD/three phase motor setup to get variable speed and really low RPMs for bowl turning.

As far as restoration goes, there's not much I need to do. I got a lot of the old dust off the lathe. There was a fair amount, as it basically went unused for five years. The bearings in the headstock seem to be in great shape. I waxed the bed and anything that slides on the bed, so the tailstock and tool rest can be moved much more easily.

The wheel on the tailstock seemed to be a lot tighter than I would like. Disassembling the tailstock, cleaning out the gunk and cleaning the taisltock shaft, and greasing the Acme screw threads and where the tailstock shaft rubs against the housing of the tailstock helped a little, but what ultimately happened was that there was a groove in the tailstock spindle that a setscrew sits in to stop the spindle from being advanced too far. I knew that the sides of the groove were scored a little, but I didn't notice that the sides of the groove protruded up the tiniest bit, enough to cause the binding. Putting the spindle in backwards confirmed this. After about 2 minutes with a file to bring those edges down, I was in business. The tailstock moves like a dream now.

I still have to run a 220V circuit to the spot where the lathe is, and finish maneuvering it into place, once I'm sure that my tune up is finished.
 

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Wilbur,
What a cool lathe! Do you know what kind of wood the bed is made from?

Understand that you intend to switch to VFD system, but it would be interesting to know what speeds you have available as is. Easy to calculate, just ratios of pulley diameters.
 
Hi Richard,

The bed is glued up from long pieces of microlaminated plywood, and is 2" x 6", more or less.
 
Must be perspective, but it looks like the countershaft is reducing the speed from the motor, then increasing it to the spindle in photo three. Strange thing to do.

I would not waste my dollars on a variable speed anything. More than enough reduction there for what you'll turn, especially if you spend a few extra moments making your blank as close as possible to balance. If the setup is "factory" you'll have ~200 low end, per manual. Already slow enough that your muscles can react and overfeed into gaps, so much slower will involve even more self-restraint to leave the tool on the rest and wait for the high spots. Slow enough on the 3000 I turn on, and it's no Conover! Until you're turning on the machine you'll never know what it's capable of doing. I'm betting you'll end up using the ~350 and ~700 speeds, as I do.

First and cheapest mod might be to replace what looks like a 2" diameter on the motor shaft with a 1.5" if you are intimidated by the low end.

Note those speeds result in vastly different fpm at rim and bottom of a bowl, which is why you already vary the feed rate on the tool for best work. That's even easier than stopping and changing a knob or a belt.
 
Feet per minute. Six hundred revolutions brings the same point past the gouge 10 times a second no matter where the point is located on the turning. The difference is the rate of speed at which it passes, measured in units of your choice. Furlongs/fortnight is my favorite.

So slowing the feed rate of the tool and narrowing the shaving compensates for the slower transit rate as you cut toward center, or speeding/broadening it compensates as you cut from center. I like broad shavings which favor slower speeds, because I like to have a lot of bevel referenced. I still get some bevel burnishing, but I don't get near the heat on the surface as those who hit the same spot more often, thereby avoiding hardening the surface and compression rings. Cuts down on sanding.
 
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