Planer Thicknesser Configuration

[deema]

I am trying to work out what is the best arrangement for a planer Thicknesser. There appear to be two schools of though by the manufacturers.

In the older machines such as Wadkins, Robinsons etc and the only British machine manufacture Sedgwick, the infeed and out feed tables do not lift up and the dust extraction hopper is moved to either above the machine or within the Thicknesser depending in what mode you want.

All the other modern machines I can find have either the out feed table, or both tables lifting up and the hopper rotating to switch from planing to thicknessing.

I don't understand why this trend seems to have taken place, and what are the virtues of the tables lifting.

I have tried to look at this as an engineering problem and can find no merit in the lifting tables and complete logic in having the tables fixed. The reasons for my think are:

The planer operation requites the indeed table to be perfectly aligned with the outfeed table. The two tables must also be completely aligned with the spindle. If any part is out of alignment the machine will not plane properly.

The older machines with all cast iron frames ensure that this configuration is maintained. The guide surfaces are precision machined which ensure that alignment can be taken for granted. The Sedgwick machines, MB and CP also have a complete cast iron frame supporting all, of the moving parts and also benefits from this wonderful system for keeping things aligned and where they should be.

The cast iron frame also improves the Thicknesser, it provides a solid frame above the spindle ensuring that the spindle mountings do not flex and move causing errors in maching. There is significant force on the spindle as the wood is driven through it and the spindle is pushed up and will move if anything can flex. The Thicknesser table also mounts into the cast iron frame which again ensures that everything is held solidly.

The lifting table arrangement does enable the spindle to be accessed easily and also allow the indeed roller of the Thicknesser to be cleaned very easily. However, this arrangement of lifting the beds causes the alignment of the beds to the spindle to change every time. The use of 'heavy gauge plate even at 4mm for housing the thicknesser and mounting the spindle is when compared to the forces being applied 'flimsy'. Having looked at the rigidity of the models available, from Startrite, Jet, Felder, they all suffer from having support frames for the two beds that will flex.

Clearly if you are processing soft wood and not using the full capability of the machine either in width in thickness the forces and weight that the machine has to support are not that great.

My acid test, which is rather crude, is to place a straight edge across the tables ensuring that they are aligned. you would be surprised how many new machines tables are not aligned in a show room! I then sit on the end of one of the tables. This simulates the weight of a good sized oak beam. With the exception of the modern Sedgwick and the older British made machines, everything else moved and flexed. If the degree of movement i have seen in this test was 'normally' apparent it is sufficient that I would have adjusted the beds to make them coincide again.

I have also used a dial gauge on one of the beds to check the spindle alignment, lifted and lowered the tables io friends machines which have a good heap of saw dust from use around them. In all of the machines i have seen the tables come down onto a reference surface that 'ensures' alignment again. If this reference surface has any residue on it, which includes resin, the tables will not realign again with the spindle (if its a dual lift system or with anything if only one table lifts) Taking the dial gauge and running it the full length of the spindle referenced to the table shows a change from the initial reading.

The amount of user effort to lift a table or tables, then swing the hopper into the new location after lowering the Thicknesser table is more steps than simply moving the hopper from above to below the machine.

I know I must have my logic twisted somewhere, and would appreciate any views in what I am missing and why almost all manufacturers except Sedwick have moved to this arrangement of lifting tables.

 

[munkypuzel]

I am a man of much fewer words than your good self, but have often wondered exactly the same thing!
I am guessing that money has somthing to do with the decision, but cant really see logic in that either..

I use a Sedgwick, but have also owned a Scheppach, with removable table and startrite with the lift up arangement, happiest with the Sedgwick.

 

[ndbrown]

I am guessing that not everyone will agree with what I have written below!
I will start by saying that I have very limited experience of using a Planer Thicknesser until fairly recently. I now own a Sedgwick and have been recently posting here on my experience of a complete and total rebuild of Sedgwick - but I have never used it yet, soon though!

My only experience of using a planer/thicknesser is a 12" Wadkin BAO/S, same arrangement of fixed tables as the Sedgwick. From an engineering point of view the Wadkin is massively constructed for the job in hand, and there I suspect is also it's downfall. With some care and maintenance it will probably last several working lifetimes. Great for a family joiner business going down through the generations but not so good if you want to sell volume machine tools and have customers replace them when the next greatest must have gadget comes along. Cast iron parts are heavy to move, take time to age before machining and are dirty to machine when you do get to that stage. This makes the whole production process much more expensive than CNC punching and robotic welding the cabinet. Having said that, in my mechanical engineering experience, the all cast iron construction confers all the benefits you have already stated. Even with all the high technology and new materials we have, cast iron is unsurpassed for most woodworking machine tools.

However, for the home / hobby woodworker (that's me), there is another problem with the all cast iron approach. Unless you have a fairly large workspace and a decent floor to take the weight, most of these older machines such as the Wadkin are just not practical for most of us (small Sedgwick excluded). They are incredibly heavy to move, so really need to be placed in a static position. They also tend to have generous three phase motors which is obviously something that many people on this forum have managed to work around with converters and inverters.

The smaller Sedgwick (PT255 series) is a machine I am now fairly familiar with in my strip-down and total rebuild https://www.ukworkshop.co.uk/forums/sedgwick-pt255-strip-down-and-rebuild-t66864.html .
I have seen it written some time ago on this forum that they are not as well built as the 12" Wadkin and if you examine them side by side you would probably agree that the Wadkins are a "cut above" in engineering terms. However, the Sedgwick is exceptionally well engineered for the job in hand and is a masterpiece of simplicity compared to the Wadkin.

I originally looked at a Record PT107 when it first came out and then a Hammer A3-26. Both of these have the lift up tables and sheet metal cabinet. I preferred a machine with more cast iron and fixed tables. I opted for an older Sedgwick PT255 because they are fairly readily available secondhand and good value for money. This allowed me to buy the machine for what I could afford and spend a little time and money over the winter rebuilding it (actually I suspect I have probably spent as much as buying the Record machine new now!). The PT255 is probably the most cast iron content machine that you could fairly easily accommodate in a smaller home workshop (single garage size).

I was initially disappointed when I stripped the Sedgwick down to it's last nut and bolt as there is not a lot to it. However, you definitely gain a respect for it when you rebuild it and see how simply engineered it is. The over and under planer is a great arrangement. Once you get it set up, it should remain fairly accurate.

I am aware that I am starting to sound like an advert for Sedgwick here, if so I really apologise. I have NO connection whatsoever with them. In my experience, their website is terrible, when you call them
you get straight through to a human who surprisingly is not a receptionist and can answer you questions! Although not a complaint as such, they seem to be stuck in a time warp!

I don't know how well Segwick are doing commercially with their over and under planer/thicknesser arrangement, but they are "swimming against the tide" of the big boys with their lifting tables and predominantly sheet metal construction. They are British though and one of the few still in business an I for one hope they remain in business for a long time to come. Like the 12" Wadkin, I think they got it right with fixed tables and can only agree with your observations.

Nigel

 

[deema]

Thanks for your thoughts, the Segwick you have is a brilliant machine. With a cast iron upper half and a sheet steel bottom half (we're nothing to do with accuracy is located) seems to be the best of all worlds keeping the overall weight down.

I have looked at the Powermatic range of products from the USA and they have a really nice solution for moving kit around. They have a set of wheels that are permanently connected to the machine that can be raised or lower by an external handle. All the wheels are driven up or down by a chain running around sprockets inside the body of the machine. You get all the benefits of mobility, and stability while moving it as well as stability of having the machine on the floor when in use.

Again, this system does not seem to have been adopted in Europe, where the trend seems to be of either having light weight machines or mounting machines on a boggy with wheels. This later solution I have adopted and its awful. Vibration is not damped down no mater how well levelled the machine is on castors. I'm going to try mounting my kit on oak sleepers and use a small pallet truck to move them. I have found one that folds up when not in use and will go under my work bench

I recognise all the comments about manufacturing costs etc, but looking at the cost of a new Sedgwick compared with say a Hammer or a Felder, the Sedgwick makes a good investment. However, my impression like you is that Sedgwick are not growing and Felder are?

I wonder if its the very nice digital gauges that are swaying people's buying decision rather than the practicality of the actual working end of the machine.

Like you I am not connected at all with Sedgwick, apart from also being a UK citizen working in one of the dwindling manufacturing companies making steel products......but not for the woodworking industry. I therefore have a bit of a passion of trying to understand why British companies are not flurishing when they have what I believe is a great product?