It is currently 29 Mar 2024, 15:02
Trevanion wrote:So I'm after a couple of pieces of steel with a clean machined finish and critically they need to be pretty flat, not like within a thousands of an inch flat but just flat enough. Dimensions are 150mm x 12mm x 500mm x two of number.
I'm not sure what the best way to go about it is, I could buy a couple of lumps of ground flat stock/gauge plate for about £100 which I am familiar with but I don't actually know whether they're dead-flat or if they may have a slight bow to them.
Alternatively, I could get some rough flat bar and have it machined flat by a local engineer, but that's probably not far off the same price if not more expensive.
Is there any other options I'm not aware of that may be worth cosnidering? It might be a little over the top for spindle moulder fences but I can see myself getting annoyed with the existing unflat and bowed aluminium plate fences fairly quickly
RogerS wrote:Why not fit a decent false fence out of MDF ? A lot less hassle IMO. And TBH, my spindle moulder fences aren't that great but the amount of bow etc makes damn all difference.
Trevanion wrote:RogerS wrote:Why not fit a decent false fence out of MDF ? A lot less hassle IMO. And TBH, my spindle moulder fences aren't that great but the amount of bow etc makes damn all difference.
There will be timber sub-fences attached to the front of the plates. The main sticking point is how the fences travel along the fence casting and clamp to it, I want there to be absolutely zero play (IE, rocking back and forth on a high spot) and both fences to be absolutely parallel to each other, otherwise trying to do accurate work is just a nightmare.
Mike Jordan wrote:This is a machine bed made of 20 mm mild steel surfaced with a thing called a fly cutter. I think that may be a more sensibly priced process. Unfortunately I had it machined more than thirty years ago so if I could remember the price it would be meaningless. As already suggested jacking screws with lock nuts will sort any discrepancies between the plates and supports.
RogerS wrote:Mmm...not knowing how your fence is fitted, it's hard to make any accurate comparisons. The fences on my Hammer combi have set screws behind them which means I can get the fences lined up and co-planar to each other. I never move them. So that eliminates most of your concerns. As for any bowing or cupping then that's taken care of by the timber sub-fence bolted to the front. I never move those fences. I have a stack of pre-drilled, pre-cut sub-fence blanks and just screw them on when the old ones get nadgered.
Mike Jordan wrote:.... I can't see how a board can be easily fixed to the face of the alloy fences.
Mike Jordan wrote:I will be interested to see the photos, I've seen pictures of spindle moulders with alloy sections used as fences, they seem to rely on running the workpiece past the central appature where the cutters protrude to make the cut. It's always been my practice to use a sacrificial " spelch board" pushed back onto the rotating cutters. My understanding is that this arrangement is now part of the requirements for workshops where persons are employed. I can't see how a board can be easily fixed to the face of the alloy fences.
Trevanion wrote:Mike Jordan wrote:I will be interested to see the photos, I've seen pictures of spindle moulders with alloy sections used as fences, they seem to rely on running the workpiece past the central appature where the cutters protrude to make the cut. It's always been my practice to use a sacrificial " spelch board" pushed back onto the rotating cutters. My understanding is that this arrangement is now part of the requirements for workshops where persons are employed. I can't see how a board can be easily fixed to the face of the alloy fences.
Mine are literally 10mm extruded flat plates, not the profiled stuff you’re thinking of. I almost never use false fences, I’d definitely never make any money if I had to do that for every cut. The SCM moulders have Tufnol inserts at the cutter ends of the fences which can be swapped out for a piece of timber to break through, with digital fence control this is quite a relaxed operation compared to doing it manually. The SCM fence plates do cost more per fence than I paid for the Sedgwick moulder though
RogerS wrote:
Dan..you're missing my point. Keep the two fences in the same position..wide enough to let your widest cutter come through. Make lots of blank fences to span the two fences and cutter gap. All the same size. I use 9mm ply. All drilled with the same countersunk holes that correspond with the tapped holes you made in your fences. So it's a no-brainer to screw on a new false-fence if you need it...then gently break through against the cutter. I nudge the cutter up and down a tad just to clear the cutter from rubbing on the false-fence. Job done.
If the job is likely to repeat then I keep the false-fence hanging ready for next time.
Malc2098 wrote:Would this be of any help?
Trevanion wrote:RogerS wrote:
Dan..you're missing my point. Keep the two fences in the same position..wide enough to let your widest cutter come through. Make lots of blank fences to span the two fences and cutter gap. All the same size. I use 9mm ply. All drilled with the same countersunk holes that correspond with the tapped holes you made in your fences. So it's a no-brainer to screw on a new false-fence if you need it...then gently break through against the cutter. I nudge the cutter up and down a tad just to clear the cutter from rubbing on the false-fence. Job done.
If the job is likely to repeat then I keep the false-fence hanging ready for next time.
I'm not missing the point and understand the technique, but that simply won't work for the way I personally like to run a moulder.
RogerS wrote:Fairy nuff. I'm interested to know how you do things as I like to learn different ways of doing things.
Trevanion wrote:RogerS wrote:Fairy nuff. I'm interested to know how you do things as I like to learn different ways of doing things.
There isn't much to it really!
What I'm comfortable with isn't necessarily what anyone else would be comfortable with but 99% of the time I run the moulder without a false fence, the times I do use one are usually when moulding very short or fragile pieces (such as narrow glazing bars) or doing a moulding on the outside of a curve by way of just referencing off the centre point of the cutter and bearing against the fence above it.
Generally, I will set the fences within 5mm of the cutting circle of the block which is usually enough support for most cuts without the workpiece "dropping" into the cutter block on the start and exit of cuts. The nice thing about having nothing above the cutter block is that you can take the block out, swap another block in or change knives to a particular moulding that requires the exact same fence depth and possibly height setting without upsetting any of the setup that you've already done, some tongue and groove cutters are set up like this and a lot of window and door tooling systems are designed to work off a moulder that's fixed in position. Interesting to see how machine type/design drives work practices. Although I can remove my fence and hood as a unit and then replace in exactly the same position, I agree that changing blocks is difficult if the cutters are projecting through the fence. However, the odd times I've not had the false fence fitted and tried to change the block without moving the fence/hood assembly has often proved nigh impossible without moving the hood forward to allow the bock/cutters to clear. Your point re window/door tooling systems is a good one.
With the fences independent of each other you can perform "offset" cutting by setting the outfeed fence to the lowest part of your cutter (the very tip of a bullnose tread, for example) and then adjust the infeed fence to however much you want to take off the material, with perfectly coplanar, square, and straight fences this works much like a surface planer would and you can achieve very straight mouldings. It's especially good if you need to take a little bit more off each time to make the workpiece fit into something as you just keep refeeding the workpiece and it takes however much off you like per pass.Agreed. I'd have to take the fence off if I wanted to do this. Which is probably why I rarely do it !
Conversely, you can also work to an exact width measurement by setting up the outfeed fence correctly for the cut and then take the infeed fence out completely and ideally replacing it with a hold-down spring, and then clamp a piece of timber to your table the exact width you desire away from the outfeed fence. Run the workpiece along the piece of timber with the hold-down spring pushing against the impromptu fence to prevent the cutter from dragging the workpiece into it, ideally, you'd have a powerfeed on the outfeed side but you can do it manually just the same and you will end up with workpieces of the desired dimension without too much faffing about.I just can't get my head round this one Tried sketching what I think you're saying but NBG.
RogerS wrote:I just can't get my head round this one Tried sketching what I think you're saying but NBG.
RogerS wrote:I'm being dim here. In your post above you said
clamp a piece of timber to your table the exact width you desire away from the outfeed fence.
but I can't see that in your diagram.
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