Is cast iron always best?

[ike]

I've noticed that many forum members consider cast iron topped sawbenches and planers to be 'superior' to those machines that aren't built with cast iron. My bread and butter comes from working as a product mechanical designer (I wish I'd studied Furniture Design all those years ago, instead of Mech. Eng.!). I find choosing the material for a product or some component of an assembly can sometimes be a complex decision, and always must consider in context of 'Fit, Form and Function'.

With regard to the (apparent) trend towards cast iron for non-industrial woodwork machine tools, e.g. the Scheppach P/T for one, I don't agree that cast iron is necesarily superior, and certainly cannot understand why it should cost the consumer so much more. There's nothing much cheaper than the sand cast process, or the relative cost of iron as a raw material. These manufacturers' I believe are switching to cast iron to save manufacturing costs and at the same time improve their profit margins. Sure, cast iron is used in industrial machines because it's rigidity and mass becomes a more important property where much greater stresses are imposed with high feed rates etc, but does it really make much difference in (predominantly) the home user market?

The fact is, China can mass produce cast iron cheaper than anywhere else in the world and manufacturers are all being forced to go this route or die (demise of Kity?). As an example of whether cast iron is better or not, arguably the Scheppach HMS 260 is best in it's class for planing quality not withstanding the fact it is made entirely of fabricated steel sheet. I have one of these myself but had also used them some years ago as a woodwork teacher. Their performance is excellent. If because of their lower mass, they have a higher resonant frequency and vibrate slightly more, then I haven't ever noticed this translating to a problem with surface finish. In fact, what a clever design it is, when you can unclip the P/T unit from it's base and carry it e.g. to another site. Can you do this with a cast iron machine? Regarding the new HMS 260Ci, have Scheppach really made every effort to improve it's design? Does it still have a pitifull maximum 140mm thicknessing capacity. Have they improved the abortion of a dust chute that requires you to laboriously wind the thicknessing table right down every time you want to side and edge?, and what about that nasty hand wheel? No, I suspect it's as much to do with marketing (the CI trend) and manufacturing economics as any other criteria.

I'm not argueing that cast iron machines are better or worse, but that we shouldn't allow ourselves to become blinkered in any way. I believe this forum provides generally objective and informed product reviews, and in doing so provides both the established woodworking community and would-be woodworkers a valuable service. May it continue so.

There, it feels good to sound off!

Ike

 

[Alf]

Ike,

Interesting points. The technicalities behind cast iron and such are a closed book to me, but I do think a lack of lighter weight machines could be a genuine problem for some home users. Typical really; you wait for at least an option to get cast iron machines, and suddenly there seem to be nothing but. Feast or famine. :roll:

Cheers, Alf

 

[gidon]

Hi Ike
I tend to agree with points in your post. And it's interesting to hear about the cost of manufacture - makes sense.
I too have the HMS260 - with steel. I find exactly the same frustrations. But none related to the bed being steel - it's still pretty heavy to shift around even with the appalling Scheppach wheel base! But the bed is smooth and I don't get any significant vibrations.
I think it would be a real shame if these lighter machines become no longer available. I'd have a job getting 150kg up a steep slope and lots of steps to the back of my garden - and I can't be the only one.
Cheers
Gidon

 

[Jake]

I agree too!

Old steel HMS260, tables, as everyone says are the least of its problems (I do like the look of the improved fence on the CI, though). Festo CS70, all aluminium and no problems so far, after, that is, 5 deliveries to get a dent free one, but that's another story. In fact the only cast iron thing in my workshop is the worst pile of *don't swear* in there, a pillar drill bought from B&Q 'cos I needed it that instant. I'd trade it for an all-ally Festool pillar drill in an instant if they did one and I won the lottery. But then again, I'd go for a Meddings too (with or without tassels before someone asks).

With a cellar 'shop, and a couple of flights of winding stairs to negotiate, cast iron would be -ve point for me. And as I'm doing up a house, picking up the saw and carrying it to the room I'm working in saves so much time. When its up and all extensions are on its as big as proper cabint saw and I've yet to have problems with stability.

I've always thought that there is a degree of US infection in this. The Americans build Harleys for gods sake, and their cars are brute force pig iron. Hardly a land where sophisticated engineering rules all.

But then, if I had an aircraft hanger and that lottery win, I don't think Felder and Alterndorf do aluminium tables.

Jake

 

[NormanKing]

and certainly cannot understand why it should cost the consumer so much more

I wonder if much of this increased cost is down to distribution charges because of the additional weight of cast iron tools?

 

[Anonymous]

Hi Ike

I agree with most of your points and have mostly aluminium tables on my machines.

However, it is definitely the case that cast iron machines better than aluminium for mitre slots etc.

As you say, there is little other advantage in using iron and I strongly (weakly??) dispute the claims that the weight helps - I cannot even lift my ALUMINIUM topped table saw, ALUMINIUM topped planer/thicknesser and ALUMINIUM topped bandsaw.

I suspect the fallacy comes from the engineering industry where lathes, millers etc. are very precise machines and always have cast iron beds, thus we woodworkers assume that cast iron is the best for us too.


Cheers

Tony

 

[ike]

Undoubtly so, The distribution chain will simply pass on increased shipping costs to Uncle Tom Cobbly et al. I'll bet Scheppach are still improving their margin simply through cheaper manufacturing. Compared to even 3 years ago, I too have to now source directly from Taiwan manufacturers for certain components that are just too expensive from UK/European suppliers.

 

[Mike.C]

Hi Ike,

I agree with some of your points. But in my view when it comes to cast iron fences they beat aluminium hands down.
I have used a number of planer/thicknessers with aluminium fences (Scheppach, Elektra Beckum etc) and their biggest fault has always been their fence going out of true. Yet with my new cast iron CT150DL planer when i set the fence it stays set.

Regards

Mike.C

 

[Jake]

I agree with some of your points. But in my view when it comes to cast iron fences they beat aluminium hands down.

MIke,

I think that's got more to do with the engineering than the material. I think the HMS260 old-style fence is pretty woeful, but then I guess was engineered down to a price. There is no particular reason that the fence support had to be made so flimsily, other I guess than cost. Cost considerations aside, a far superior mechanism could have been made of pretty much any material (metal, I should say). My festo saw's fences are all aluminium, but when you set them to 8mm, or 8°, they stay right there as long as you like.

Jake

edited cos addressed comment to Ike instead of Mike apologies to both

 

[Jake]

pretty much any material (metal, I should say).

On second thoughts, that was very polite of me, possibly too polite. And now I'm talking to myself. The boredom of being stuck at work late..

Jake

 

[Bean]

Mike
That sounds like a problem with the locking mechanism and not the material the fence is made of (If I understand correctly). An aluminium extrusion should not move much if at all when used in the correct manner.
I am thinking of replacing my fabricated steel fence with an extruded fence as I believe it will be stiffer.

I think Ike may be right about the tables in cast iron as castings are dirt cheap in china, possibly cheaper than extrusions, but after all its very good marketing :wink:

Pesky things engineers. :wink:

Bean

 

[Mike.C]

Jake,
Festo CS70, all aluminium and no problems so far, after, that is, 5 deliveries to get a dent free one.
I rest my case. That is totally diabolical. I would have sent it back after the second time. It sounds like it is pot luck as to weather you will get a good fence.

Bean,
Weather it is the aluminium fence itself or the locking mechanism, my point is you get this sort of problem with A LOT of aluminium machines. You only have to look around the different forums on the web to see this.

I am not saying that aluminium machines themselves are bad because most of them are not, and this includes the Scheppach HMS260 and the Elektra Beckum 260M it is just their weak points are the fence.

On the other hand i have the Scheppach 2500 table saw which has a first class fence, an excellent table and cuts straight and true every time.

Regards

Mike.C

 

[Jake]

Jake,
Festo CS70, all aluminium and no problems so far, after, that is, 5 deliveries to get a dent free one.
I rest my case. That is totally diabolical. I would have sent it back after the second time. It sounds like it is pot luck as to weather you will get a good fence.

To be fair this was all shipping damage by the courier company (mostly) between Minden and me, and (for one particular part) between Germany and Minden. Had more to do with inadequate packaging than anything else. When Minden brought the third delivery to me rather than using a courier, it was fine apart from the one part which was woefully under-packaged with only one layer of cardboard protecting its end. That kept getting damaged between Germany and Minden hence the two more deliveries. If it had been cast iron, I suspect it would have shattered into pieces.

Jake

 

[ike]

All shortcomings with aluminium fences, and other bits that flex etc are most unlikely to be a material problem, it's just poor design. Take Kity as an example (perhaps an unfortunate choice given their demise). Kity machinery I think is generally well designed. OK, the finish wasn't ever spectacular but they used a lot of cast aluminium as well as extrusions. Once you hard-anodize aluminium (the dark grey finish you see on some tables), it's extremely durable and for the level of use by the home-craftsman, it just won't wear out. I also design aluminium extrusions. There's always a pressure to minimize the cross-sectional area to keep the cost down. You can make very thin walled extrusions that with suitable geometry, can be extremely rigid. Get it wrong and you end up with for example, a flexy fence. It all comes back to the standard of design and engineering.

Ike

 

[Philly]

Hi All,
Just my twopenneth worth- everyone (without exception) who has laid eyes on my Jet surface planer goes "now I understand". The penny drops! :lol:
I can't speak for all cast iron machines, but the majority i have seen and used are built to last AND perform their function impecably.
Get your hands on one for an hour and see if you agree,
regards,
Philly

 

[Adam]

I'm interested in this thread. I was talking to NMA about this new dado blade set they sell, on both the TS2500, and the TS4010. It's only possible on older saws, if you replace the table with cast iron - about £300. That sounds reasonable to me. Now if you consider some cast iron tables with induction motors are coming in at £500, including retailers markup, and manufacturers profit what is it exactly that is being degraded to bring the saws in for this price?

Something must give surely? Motor quality? Bearings? Poorly machined cast iron? The example of the Jet jointer is a poor one in my opinion, on high-end machines, they are expensive enough to not have to cut corners, and in those circumstances it's the best material for the job - but getting an entire table saw, with sliding cariage in at around the £500-£700 surely means something must have been comprimised? Even something not visible to us like the working conditions, or health and safety of the employees in China.

Adam

 

[johnjin]

I also am very interested in this thread.
First of all let me say that in my opinion when you have used cast iron for a while then anything else will seem cheap afterwards. This is why all the really professionally built machinery are built from cast iron. To say that it is not necessary because it is for home use or for small production runs is missing the point a bit. I do not see why, just because someone wants to do a hobby, or is a small manufacturer he must use inferior quality machinery. There is a huge variety of quality in the shops and that is how it should be. The purchaser gets to choose what he wants and pays the price he wants.
As for the cost of producing cast iron as opposed to pressed steel or aluminium tables it comes down to manufacturing costs. Cast iron is by far the cheapest to produce in its rough form but then the costs start to rise with the more machining that is done on it. Pressed steel is expensive to produce in the beginning because of the cost of making the press moulds so is only viable when you hope to sell many thousands therefore bringing the cost down significantly. As little as possible machining would be done as machining steel is expensive. Aluminium tables are usually quite a mixture of diecasting and machining. Diecasting is cheap and machining aluminium is very fast which helps compensate for the cost of the aluminium. Everything comes down to labour costs which is why it nearly all gets made in Eastern Europe or the Far East. When you can pay someone $50 a month instead of $20 an hour every manufacturer is going to jump at it. Now $50 dollars a month might not seem very much to us but it can be pretty good pay in some of these countries. The working conditions and safety I expect are mostly non existent but these people are fighting over the jobs cos it puts food on the table.
The quality of the finished product need be no different to anything manufactured in the west as these Western Companies should have their own quality control on the site. As far as shipping of products goes, it comes down to volume, not weight, that puts the cost up. So it really has no bearing on what the part is manufactured from and is also one of the reasons that we have to assemble so much when we buy it. But please note it is the larger parts we have to assemble not the smaller ones as these will not change the volume of the product. As for having lighter machinery so that we can take it to the site with us, I would have thought that there was plenty of light stuff around if that is what you want. But people then complain that it is not as good quality as the Cast Iron machinery. So it comes down to the point that if you want quality buy Cast Iron, if you want portability buy Aluminium and if you want something in between buy steel. What Ike said in the beginning is right in my opinion. There is no real reason why Cast Iron machinery should be any more expensive than anything else.
This has turned into quite a ramble, and is of course just my opinion, for what it is worth,

All the best

John

 

[Nigel]

Hello I have finally delurked after reading this forum for quite some time
I am a Norm fan as it was he who got me started on this hobby (the loml says addiction)
My question in this post is how flat is acceptable for a cast iron table on a band saw, I have purchased a Record BS300 and find the table is distorted where the slot is cut for the blade ie there is a step of about 1mm across the slot which the bolt supplied by record to adjust this fails to do,also the blade insert stands proud of the table and being plastic seems to distort with the table,
should I reject the saw or is this the what I should expect at this price
I have been cutting wood only in setting the guides up and in that time the no-volt switch has failed ,I am not impressed,
your comments would be appreciated

 

[Aragorn]

Take it back!

P.S. Welcome to the forum!

 

[johnjin]

Hi Nigel

Welcome to the forum.
For what its worth I would send it back as totaly unacceptable. I would not expect to see more than 0.1 m/m across the slot. And then for the NVR switch to fail I would say that that is more than enough reason for it to go back.

Best of luck

John