Hello
I have purchased an old Altendorf panel saw (made around 1980). I have squared the cross cut fence up perfectly. The rip fence is parallel with the blade to about 3/4 of a mm, to avoid the saw binding when I rip sheets down, I don’t really use the rip fence for accurate cuts anyways.
I have been cutting down melamine sheets to no larger than 600×1000 for a kitchen I am building, using the cross cut fence. The sheets are perfectly square however they vary in size by 0.5mm to 1mm. I’m not adjusting the fence during the cuts. For example if I cut 10 pieces at 600 wide, the fence stays set at 600.
I can only imagine this is happening because the flip stop on the cross cut fence has a little play in it. As I am pushing the sheets through, the flip stop is moving by half a mm or so.
Has anyone experienced this with the old panel saws and come up with a work around? Or could it be another issue?
Also what would be the normal tolerance in a kitchen fab shop? I looked at a few installations and +\- 1mm on the cuts looks to be acceptable.
Replies
The TS I've used for nearly a quarter of a century is a mid-priced (much less than an Altendorf) Scheppach with a sliding cross-cut fence & table that can just manage a full sheet (8ft X 4ft) when used with an extra outlier support. Cutting up such a sheet can be done to a repeatable accuracy approaching 0.1mm using the micrometer-adjustable stop on the sliding carriage fence. It stays that accurate (and square) for years at a time.
Unless your Altendorf has been damaged, abused or otherwise attacked at it's cross cut fence stop or in the sliding carriage gib-ways, you should be able to do the same. Is there any play at all in the fence or the sliding table it's mounted on? You should be able to detect any by feel.
I'm not clear why you mention the rip fence or why you set it off-square by such a large amount? One should never use the rip fence and the cross cut fence at the same time, since one or the other will be redundant; and using both for the same cut introduces a number of safety issues.
When I use the rip fence, it too benefits from a micrometer on the fence rail allowing cuts to be made approaching a 0.1mm accuracy, time after time.
In short, is it your saw making your cuts inaccurate or something about your technique?
Lataxe
It hasn’t been damaged, but it is 50 years old. The saw stays square. It’s the repeatability that has me. There’s no play in the table, otherwise it wouldn’t be cutting square. I don’t use the rip fence for accurate cuts, only the cross cut fence. If I set my rip fence perfectly square, the timber will bind against the riving knife and flick back at me.
It might be my technique, I’ve only had the saw for a few weeks. What do you mean by micrometer adjustable stop? Is this something you have put on your fence? There’s no way I can get accuracy of 0.1mm by adjusting the fence and looking at the tape provided.
The attached pics are of the rip and crosscut fences on my TS, with their included micro-adjustable gubbins calibrated to 0.1 mm smallest-adjustments.
The cross cut fence flip-down stop can be moved about 20 mm in total, once the stop mechanism is locked to the fence, by turning the micro-adjuster knob. The increments shown on the knob represent 0.1 mm change, with one full turn of the knob covering 2mm via the 2mm pitch thread used by the adjuster.
The rip fence can also be moved, over a similar range, by using one of the locking levers to lock the fence to its rail then turning the adjuster knob, which has 0.1mm increments on its scale but moves on a 1mm pitch thread (one complete turn moves the fence 1mm). Once the desired setting is obtained, a second lever locks the fence in place on the rail and on the table.
I'd assumed that your Altendorf had a similar arrangement, as most EU tablesaws do now .... but I suppose your saw is 50 years old ...... .
The ability to make such small changes to fence settings - and for them to result in accurate changes in the actual cuts - is of great utility. I make many parts to a very exact fit by initially cutting them too big by a half millimetre then sneaking up to an exact fit by taking off a fraction of a millimetre, perhaps via two further tiny cuts, until "it fits like a chicken's top lip". :-)
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Your variation in cut-widths on the Altendorf must be due to something in the saw being either slack or worn, so that each cut can vary according to what the slack or worn part is doing at the time of the cut. I imagine the difficulty will be in determining what, of several possible culprits, is the slack or worn part.
First check - does anything of the fence/table move at all if you push on it after it's supposedly been fixed in place? Is there any play if you push sideways on the blade when it's stationary?
It could be the fence, the slideways the crosscut table runs on or something else in the crosscutting gubbins. But it could also be something in the blade and its arbor. A serious examination of all the parts is probably needed. But perhaps some partial disassembly and reassembly (with appropriate lubrication) will fix things, even if the specific cause is not definitively discovered?
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The rip fence, by the way, can be parallel to the blade without causing work to bind and kick back. The trick is to have a false fence cheek that runs down the fence side that faces the blade but which is ended opposite the centre of the blade. And to have the blade high for most cuts.
This means that the workpiece is only tight between the blade-cut edge and the fence as far as the middle of the blade. Once the workpiece gets past that, the short false fence cheek means that there's a fairly large gap between the back of the cut workpiece (where the saw teeth rise up from the table) and the true-fence. It's therefore far less likely that the workpiece will be pushed into the rising back teeth of the blade.
To provide safety belt and braces agin' even the remaining possibility of a kickback, use vertical hold downs attached to the fence or the table top. And the guard. These will prevent any rear-rising-teeth grab of the workpiece from actually launching it at you.
Lataxe