Laguna lathes. Cast iron vs steel.......do you agree with these statements? (Video)

[odie]

Because of a related thread, I was casually looking at the Laguna 18-36 lathe for information sake only. Starting at 2:25 the narrator says that steel construction will maintain straightness and rigidity better than cast iron. Knowing that high quality industrial grade milling machines and lathes are traditionally made from cast iron, and these machines (to my knowledge) have never had warping or other quality related issues......I have my doubts that these statements are nothing but a sales pitch.


Besides that, my own lathe....an original Australian Woodfast lathe is cast iron, and I've never had these issues, after 32 years of owning this lathe!

I do believe that steel is actually MORE susceptible warping than cast iron......although if designed and constructed properly (Like Robust and Oneway, for instance) steel can also be relied upon to maintain rigidity and straightness.....

So, what do you think?

-o-

View: https://youtu.be/Mh93urQaXuA?list=TLGG_1p5sJ8effEyOTAzMjAyNA

 

[Roger Wiegand]

Both materials (along with wood, for that matter) work fine if properly engineered and constructed. Both materials work terribly if poorly designed or of inadequate quality or strength for the job, It's not like you're working to 0.0001" tolerances on a wood lathe. Cast iron, if not properly aged prior to milling, can certainly warp and be very problematic, but that's not a problem attributable to the material. Steel can deform during welding operations. You won't see either of those problems in a quality machine.

My three lathes over time have been cast iron, wooden ways with cast iron head/tail stock and legs, and now steel. My reasons for changing over time have had nothing to do with straightness and rigidity, they were all fine in that respect.

 

[odie]

Both materials (along with wood, for that matter) work fine if properly engineered and constructed. Both materials work terribly if poorly designed or of inadequate quality or strength for the job, It's not like you're working to 0.0001" tolerances on a wood lathe. Cast iron, if not properly aged prior to milling, can certainly warp and be very problematic, but that's not a problem attributable to the material. Steel can deform during welding operations. You won't see either of those problems in a quality machine.

My three lathes over time have been cast iron, wooden ways with cast iron head/tail stock and legs, and now steel. My reasons for changing over time have had nothing to do with straightness and rigidity, they were all fine in that respect.

I certainly agree with your statements here, Roger......

Poorly designed, strength could be an issue, but just wondering......do we have any examples of cast iron lathes warping? Some of them have been around for a couple of centuries, and I'm not aware of any past or current problems with them warping. (Because I'm not an expert on this subject, maybe we do have examples of cast iron warping....just that I'm not aware of it.)

--o-

 

[Kevin Jenness]

It's just marketing blather. It is possible for cast surfaces to warp without some form of stress relief but they shouldn't make it to the consumer from a competent manufacturer any more than a weldment. Here's an interesting thread on "seasoning" castings from Practical Machinist

 

[hockenbery]

I think the advantage of steel is the rigidness the makers achieve from the steel tubes under the ways.
Like ONEWAY uses and ROBUST uses on the bigger machines.

Less vibration.
Plus the stainless steel option

Cast iron is just fine too.

 

[William Rogers]

I don’t know about warping of one vs the other. However I have owned lathes with cast iron ways (PM 90), steel ways (Laguna 18-36), and stainless steel ways (Robust AB). They all work, but there are differences IMO. The cast iron work well but are can be dented and raise material requiring the need to stone it to regain flatness. Also more of a problem with wet wood causing staining/rust. They are smooth using them. The steel ways don’t dent, but not as smooth using as cast iron ways. They become “scratchy” for a lack of a better term. Also steel ways are likely to stain or rust. Stainless steel ways are the best IMO. No issue with wet wood and are just as smooth as cast iron. My preference order is stainless steel, cast iron, and lastly steel. I have never noticed any significant vibration differences relating to the materials.

 

[Don Wattenhofer]

Both materials (along with wood, for that matter) work fine if properly engineered and constructed. Both materials work terribly if poorly designed or of inadequate quality or strength for the job, It's not like you're working to 0.0001" tolerances on a wood lathe. Cast iron, if not properly aged prior to milling, can certainly warp and be very problematic, but that's not a problem attributable to the material. Steel can deform during welding operations. You won't see either of those problems in a quality machine.

My three lathes over time have been cast iron, wooden ways with cast iron head/tail stock and legs, and now steel. My reasons for changing over time have had nothing to do with straightness and rigidity, they were all fine in that respect.

Add to this is the fact that all materials have multiple grades and the precision machine tools use a much higher grade of cast iron then my green wood lathe.

 

[Tom De Winter]

On a related materials question is one better for bandsaws (in the 14" to 24" range)?

 

[robo hippy]

Old school cast iron needed to sit and 'age' for about a year before final machining. The modern 'ductile' cast iron, does not need to do this. The old Stanley hand planes would crack if you dropped them. The more modern ones from all of the manufacturers will not, at least not most of the time. So, the claim that cast iron will move/warp are baseless. When I went from my 3520A to my Robust, the only real difference I noticed was different noises.

One thing about the Laguna that I don't like is the big cone on the headstock. This was a difference I noticed right away on my Robust from the 3520. The more a piece cantilevers off of the headstock, the more vibration you get when turning bowls up in the 12 or so inch range. Note here, if you engage the tailstock, the vibration is eliminated. This is why the Vicmark is so popular. The headstock spindle is actually a bit back from the base of the headstock tower. I don't need tailstock engagement for most of the bowls I turn. I have not checked out the pressure plates on the Laguna lathes. For sure, you need a bigger one on the headstock than you do on the tailstock and banjo. The headstock is what takes all of the abuse, and does the most work. My Robust has a pressure plate under it that is the same size as the headstock base. This might be a bit of overkill, but it does work very well. My 3520, which had a cast iron pressure plate that cracked when coring some locust, and it was replaces with about a 4 by 5 inch plate. While I was waiting for it to arrive, a neighbor made me one that was 4 by 6. That seemed adequate. I tend to go for the overkill variety....

robo hippy

 

[Neil S]

I can't comment on the differences, but know that a cast iron lathe will warp/twist if mounted on an uneven floor and will return to 'true' when the legs are packed/adjusted to bring them all level.

 

[Steve Tiedman]

It's BS claims such as this ( in the video) that makes me not do business with a company.

 

[John Ames]

the only conceivable way a woodturner could have the ways of their lathe bend would be if the shop caught fire and generated 1000's of degrees of heat.... if that happens bent ways are your smallest issue

 

[Doug Rasmussen]

Cast iron has an advantage over steel in that strengthening and stiffening ribs and fillets can easily be added, not so easy with weldments.

I don't see lathe frame stiffness as a major issue. The real stiffness issue with hand turners is in tool holding. No turner can hand hold the tool rigid enough to not cause issues. Granted some are better than others.

Find a friend with a metal lathe or a pattern makers lathe. Use a high positive carbide insert and you'll get the smoothest finish you could ever imagine, even on gnarly difficult woods. All because the tool is rigidly held and guided.

 

[Bill Blasic]

In Erie PA I worked for over 37 years on cast iron machines (vertical turret vertical boring mills) 12" table to 14' tables with pieces 1 lb to some over 8 tons. All these machines were made of cast iron. On these machines steel was mainly turned. Now steel being turned can get to vibrating and it can vibrate enough to get the steel being turned on the machine next to it to also vibrate (sympathetic vibration). Had this happen a few times, not the machine vibrating just the steel. That experience has left me using cast iron, all my lathes are cast iron. I have turned on a couple Oneway lathes and it surely could be my imagination but I feel that my body or the lathe is singing. Not saying that they are bad just that I don't like how it feels using them. I have never had to adjust a cast iron lathe they have all worked as advertised as probably steel does also. I have stated in the recent past that I am getting rid of 5 of my lathes and no longer doing hands on because I have been looking beyond woodturning. I now have a CNC Router and a 3D printer and to my wife's distress I have a book coming on throwing clay😁 I have found to my delight that the CNC and the 3D printer can be used along with the lathe to do combined stuff, how great is that!

 

[Steve Tiedman]

Bill, my lathes have all been cast iron as well. I have a Oneway 1224 on order, my first steel lathe. (I don't count the monotube Sears Craftman lathe I started with in 1995, a mix of cast and steel. Darn thing was better suited as a boat anchor.) Memories from eons ago say that Oneway explained that although steel can ring like a bell compared to cast iron, their design of different sizes and shapes of steel components, welding, bolting, and so forth, work to interrupt vibration from moving throught the machine. I'm going to take their claim at face value, and I've never heard complaints from owners I knew. But with your vast experience, I know you can pick up on fine nuances that the rest of us probably never would.

20 years ago I had a chance to use the old Oneway 1018. Great machine, but the plate steel stand it uses hummed from harmonic vibrations. I'm already expecting that with my forthcoming 1224, and strategising the application of materials to the stand to quell the vibrations, if it still exists. But I know bed flexibility will not be an issue with their design.

 

[Charles Cadenhead]

@odie as you and others speculated this may be marketing BS and may not even be truthful. I don't have one of the larger Laguna lathes but my 12/16 Laguna is cast iron. The stand and control house that the electronics are in is steel, everything else is cast iron.

 

[Bill Alston]

When I did my mechanics training I was told that cast iron engine blocks were left out in the open to “season” for a year or so before machining. Provided a cast iron lathe is properly supported it should never move. Levelling a metal work lathe is done with considerable care to ensure its accuracy. Wood turning lathes don’t need this precision though do they? Anyone here work to the nearest thou or ten thou on a wood turning project? I personally would always go for cast iron as I’ve been led to believe it absorbs vibration better than any other material except *concrete.

*Many large early machine tools had massive concrete bases with cast iron and steel elements cast into them.
A guy on one of the model engineering forums built a CNC mill a while ago using “Epoxy Crete” with cast in steel elements.

 

[John Snow]

... Anyone here work to the nearest thou or ten thou on a wood turning project? ...

I can't tell if you're being a bit sarcastic, but anyone who is working on a close fit for a lidded box is working to thousands of an inch.

I don't know if cast iron will make a real difference in woodturning, though. I think the vibrations set up in turning metal are much higher in frequency than in wood, and much more "in tune" with your lathe material be it cast iron or steel. I think the most important criterion for any lathe is mass, applied to all of the components. Won't do any good if your headstock is very massive, but your ways are thin.

 

[odie]

I can't tell if you're being a bit sarcastic, but anyone who is working on a close fit for a lidded box is working to thousands of an inch.

I think the only way to consider thousands of an inch fit between lid and body of boxes.....is to keep the finished box in a temperature and humidity controlled environment.....forever! The moment any of those factors change, the wood will begin to move over time. Just how much it will move depends on size, shape, thickness, species, grain pattern.....and, maybe a few other things as well.

It's been quite a long time since I made any boxes, but when I did, the object was to get a "suction fit" to the lid. Over time, none of the boxes I made survived because of the environmental changes they endured. Quite frankly, it's the main reason I gave up on boxes.......as well as laminated bowls, too. The only way to change the metrics of this situation, is either to change to some another base material, or to stabilize wood to the point where environmental concerns don't apply.

Personally, it's my belief that @Bill Alston is correct in his statement.....as it applies to my own thoughts on the value of extreme precision to wood lathe turning.

-o-

 

[John Snow]

I think the only way to consider thousands of an inch fit between lid and body of boxes.....is to keep the finished box in a temperature and humidity controlled environment.....forever! The moment any of those factors change, the wood will begin to move over time. Just how much it will move depends on size, shape, thickness, species, grain pattern.....and, maybe a few other things as well.

It's been quite a long time since I made any boxes, but when I did, the object was to get a "suction fit" to the lid. Over time, none of the boxes I made survived because of the environmental changes they endured. Quite frankly, it's the main reason I gave up on boxes.......as well as laminated bowls, too. The only way to change the metrics of this situation, is either to change to some another base material, or to stabilize wood to the point where environmental concerns don't apply.

Personally, it's my belief that @Bill Alston is correct in his statement.....as it applies to my own thoughts on the value of extreme precision to wood lathe turning.

-o-

No arguments here. I bet the same is the case with those suction-fit drawers that some woodworkers strive for. I can't imagine they last long in a highly-variable climate.

 

[Mick Fagan]

I have the last version of Laguna's 24-36 lathe. The first thing I often need to do, is ensure the steel bed is clean and has been wiped down with dry PTFE WD 40, this makes the bed quite slippery, but also lowers the screeching noise that sometimes happens when one is sliding things along the bed. Wiping the bed down after turning also reduces and virtually eliminates surface rust forming, but the cast iron bed of my bandsaw requires the same treatment to keep surface rust at bay.

I very regularly use a Stubby lathe with a cast iron bed, it too requires a wipe down to make things smoother, but it rarely, if ever, screeches like the steel bed of my Laguna. Similarly, the Vicmark lathes I also use don't screech, but they too require something to reduce/eliminate surface rust.

My Laguna only makes a screeching noise whenever I'm sliding the banjo along dry/dirty bed rails, I'm not too sure as to whether or not the Laguna makes more noises than the various other lathes I regularly turn on; with or without my hearing aids inserted.

Yep, sales pitch!

 

[Bill Alston]

I think the only way to consider thousands of an inch fit between lid and body of boxes.....is to keep the finished box in a temperature and humidity controlled environment.....forever! The moment any of those factors change, the wood will begin to move over time. Just how much it will move depends on size, shape, thickness, species, grain pattern.....and, maybe a few other things as well.


-o-

Exactly, wood is a natural material with a moisture content that will alter its dimensions over time. How many times have I got that perfect fit only to find it far less than perfect two days later. I acclimate timber indoors before turning it and it’s still made no difference. When I turn metal on the other hand …

 

[odie]

I acclimate timber indoors before turning it and it’s still made no difference.

I question the value of "acclimating" raw wood blocks, whether it's wet or KD, or comes to your shop from within your neighborhood, or on the other side of the earth. The wood blocks I use normally acclimate for days or weeks before I get to them, but..... The main factors in the dynamics of the process, is the internal stress relief in both the first and second turn, plus the loss of MC in the seasoning evolution of one specific piece of wood.

Can someone here give a specific verifiable reason why "acclimating" wood is necessary?

-o-

 

[Kevin Jenness]

I question the value of "acclimating" raw wood blocks, whether it's wet or KD, or comes to your shop from within your neighborhood, or on the other side of the earth. The wood blocks I use normally acclimate for days or weeks before I get to them, but..... The main factors in the dynamics of the process, is the internal stress relief in both the first and second turn, plus the loss of MC in the seasoning evolution of one specific piece of wood.

Can someone here give a specific verifiable reason why "acclimating" wood is necessary?

-o-

For your work acclimating bowl blanks is pointless because they are typically of such thickness (and often, I would assume, of relatively high moisture content relative to in-service conditions) that waiting for the material to come to equilibrium with the shop atmosphere is impractical. Same for a timber framer who typically uses green wood and must allow for shrinkage in the years that it takes their work to dry out.

For a spindle turner, millworker, or carpenter using thinner, relatively easily dried material that is only going to be worked once and has to maintain its size and shape in service acclimation totally makes sense. As a cabinet and funiture maker I often rough out material for stress relief just as you do with bowls but I wait until the stock is at equilibrium moisture content with the shop and/or expected in-service average humidity. A floor mechanic in Alaska would definitely get the stinkeye if he omitted acclimating plank flooring that was milled in Missouri and wound up with cavernous gaps in the finished floor in winter.

As far as working in thousandths, there are definitely situations like inlays and turned mortise/tenon joints where very precise work is needed and will remain solidly assembled because properly fitted and glued. The movement of a hygroscopic material like wood does have to be taken into account but that doesn't eliminate the need for precision in specific circumstances. In fact the demanding detail work you do on your bowls is very precise and depends on thorough acclimation, but that happens after roughing out. I don't think your level of precision is dependent on cast iron vs steel machines though.

 

[Bill Alston]

Yes, bowl turning is another matter. I don’t do a lot of it but when I do I’m not normally working to anything finer than 1/16” 😆

 

[hockenbery]

Can someone here give a specific verifiable reason why "acclimating" wood is necessary?

It isn’t at all necessary unless you want to eliminate/minimize wood movement.

For first turning a bowl - a big wooden block is not going to reach equilibrium for years.
Turned into a bowl it will reach equilibrium in 6-14 months depending on thickness.

When doing once turned Natural edge bowls, hollow forms, wooden hats…..
The warp accentuates the ovalness of natural edge bowls. Johannes Michelson uses the warp to make hat fit.
As for hollow forms they move in pleasant ways.

Boxes, functional bowls, ornaments, pens, most glue ups depend on controlling and eliminating wood movement.
Wood must be acclimated to an MC of 8-9% so it won’t distort in the average indoor environment- area highlighted in the chart.


Wood moisture content will stabilize to its environment.
The forestry service produces this chart of the moisture content wood will move to.

 

[robo hippy]

Furniture repair shops do great business in Arizona, and other dry states. If you move from out of the area, the humidity change can be huge, and wood always moves unless stabilized or if it is petrified. For boxes to continue to fit the lids, I almost never make them more than 1 1/2 inch diameter because of wood movement problems. I have made a couple that are 5 or so inch diameter, and make them out of the same end grain piece. So, when movement happens, the lid may not be able to spin all the way around, but top and bottom movement should be the same, and the lid will still come off.

robo hippy