Lathe bed

[Grahamshed]

Having read through most of this sections 300+ pages it is fairly obvious that most people prefer cast iron beds etc for lathes.
The words CAST IS BEST seem to have been etched on my mind.

But then again......

Anyone asks for a list of the best lathes and Wivamac always seems to appear on it.

Wivamac is steel built rather than cast iron so how important is it ? Is Wivamac worth the money when its not cast ?

 

[CHJ]

With Lathe beds it's all about rigidity, stability and mass.

The first two factors maintain alignment and the mass provides damping against vibration and machine movement with out of balance loads.

Cast Iron, if made correctly provides all three, in the context of a wood lathe anyway.

Steel construction can be equal to it if designed correctly and money spent on materials, poor design and skimping on materials can result in a dog which is light and subject to flex.

Solid Bar Beds, can provide the mass and be good on rigidity and alignment once set up correctly but do rely on mounting to avoid twist etc.

Tubular Beds with hollow bed bars do not have the mass in the bed and are more critical on support alignment to maintain good tail stock alignment along the bed. No problem for between centres turning but does affect tail stock drilling. Mine is such but size matters and it takes a couple of good fellows to lift just the headstock in place, just had to make sure support bench was true.

 

[paulm]

From a user perspective Graham, I used to have a Record CL3 lathe with tubular bed bars and to be honest it was very good for everything. It was only when I started doing much larger and out of balance pieces that I felt the need to upgrade to a bigger heavier lathe.

Having looked at Vicmarcs, Oneways and others at the time I settled on a Wivamac and haven't regretted it since. You're not far from Toolpost at Didcot, why not pop along there and have a look at them and try them out and see what you think. I don't personally see the fabricated approach being at all second best to cast given the scale, mass, materials and quality of engineering used and think that is a bit of a myth put around by other manufacturers worried about the competition !

Welcome to try out mine too if you fancy coming a bit further south on the A34

Cheers, Paul

 

[Grahamshed]

Thanks for that guys, reassuring.
Paul - I did go to toolpost when I saw they had an open day but it was a bit to busy to do anything but wander round. I will be going back in the next week or so for a more detailed look. There are other lathes that appeal on paper ( rg the Killinger ) but it seems to make sense to me to get one locally in case anything goes wrong . On top of that I see they run courses so I may look into a one on one day before I purchase. I think there may even be a club based there, but not sure about that.

 

[Spindle]

Hi

Just for the record, (no pun intended ), my Record CL4 has and I'm pretty sure Paul M's CL3 will have twin solid bar beds.

I have little bad to say about the CL4 apart from the locking mechanism for the steady banjo and tail stock, which can be a bit fiddly when turning short spindles. I intend to replace them with cam lock one day but so far it's not been that much hassle.

Regards Mick

 

[Alli]

Thanks for that guys, reassuring.
Paul - I did go to toolpost when I saw they had an open day but it was a bit to busy to do anything but wander round. I will be going back in the next week or so for a more detailed look. There are other lathes that appeal on paper ( rg the Killinger ) but it seems to make sense to me to get one locally in case anything goes wrong . On top of that I see they run courses so I may look into a one on one day before I purchase. I think there may even be a club based there, but not sure about that.

I would recommend a lesson with Steve who works at Toolpost. He can give lessons from the toolpost shop where I think they have the Wivamax Lathes or from his own workshop where he has a couple of lathes one being a VB36 - very nice machine but due to the high cost I think in my case there would be an big ultimatum ............the lathe or the girlfriend. And I'm not too sure the girlfrind would win. :lol: If you want his number, let me know and I will send it too you.

I have had a couple of lessons with Steve who is very relaxed, informative chap. He is quite happy to teach you what you want to know and change the day activities to suit your needs.

Cheers
David

 

[Alli]

Forgot to mention, Have you looked at the Jet lathes. As these are on my short list when I finally get the money to upgrade.

 

[TheTiddles]

Do also keep in mind that cast iron is mostly iron with carbon in it and a few other alloying elements, and steel is mostly iron with carbon in it and a few other alloying elements. Yes they behave very differently in some instances but fundamentally they're very similar and quite heavy.

The most expensive and accurate machines I've ever used were neither iron or steel, they were built from granite. That aside, there's no reason aluminium or magnesium can't work well, they're just much more expensive than is worth using for an essentially pretty cheap machine like a lathe and the extra weight helps compensate for the vibrations.

Aidan

 

[jurriaan]

What I haven't read yet: cast iron is smooth, objects like the tailstock or the banjo glide over them easily. And it's way more rust proof then regular steel (and I can compare: I have a cast iron lathe and a home-built one with steel ways. Turning oak is something I try to prevent on the steel one

 

[Noggsy]

Thetiddles, just out of interest, what machines have you used that were made out of granite? That sounds really intriguing...

 

[Paul Hannaby]

I remember reading somewhere that cast components do not propagate vibrations like fabricated steel so a cast bed or headstock should be less likely to vibrate.

There are so many other factors in the design of a good lathe, such as the stability of the legs or base, the rigidity of the bed and the distance between the headstock bearings and type of bearings. That's before you get to things like capacity in terms of swing over the bed, distance between centres, motor power, speed ranges etc. etc.

Some years ago I spent a long time weighing up all the pros and cons and ended up buying a Wivamac DB1000 and five years later upgraded to a DB1200 for more power and more distance between centres.

No lathe is ever going to be perfect and we all have different preferences and budgets so I don't envy you having to make the decision now!

 

[CHJ]

Thetiddles, just out of interest, what machines have you used that were made out of granite? That sounds really intriguing...

Nosing in on the above;
Co-ordinated measuring machines and some Jig boring type equipments use granite as the bed for the mass and stability and slow response times to any fluctuating shop temperature/humidity changes and inherent vibration damping. Mind you a 300 ton press at the other end of the site that is modifying the pressure curve of the underlying clay and rock sub foundations can call a CMM's bluff no matter how well you try and isolate it on springs etc.

Even these are not perfect and if you need the best accuracy possible have to be calibrated on a regular basis to maintain within specification because the mechanical aspects attached to them move in relation to the surface. Even if using laser scanning rather than a Renishaw type mechanical probe the relationship between measuring source and the granite bed has to be checked before each session if you are after the best accuracy.

Then of course there are the zone tolerances of all the devices and systems you are using and you are still left with a range of results that might or might not fall within the tolerances defined on a specification drawing. Many a good part has be thrown away because someone insisted on taking the resultant printouts as gospel without the due diligence and checking of fit in practise.

A favourite trick was to ask the metrology section to provide a report of all their test setup and associated zone tolerances. Fuel for hours of endless and pointless debate as to who's measurements could be believed.
Bit like mentioning sharpening and blade setup on a wood forum. :twisted:

Best to just get used to using a Pole Lathe and have the bliss of never even considering such things.

 

[TheTiddles]

Thetiddles, just out of interest, what machines have you used that were made out of granite? That sounds really intriguing...

Lasers. Though it should be noted that if you then fit a window between the lense and the head no matter how well set up the machine is it's no good if the window gets grubby!

High-precision engineering is the same as everything else in life, ultimately it has to work, flash machinery is just as good a a blunt stick if what it makes doesn't work right. Same as lathes, the most expensive custom machine is going to give poor results if you can't use the £30 skew chisel on the £10,000 machine!

Aidan