Paxolin /SRBP

I need to cut accurately 20 thou and 32 thou paxolin sheet. It is prone to shattering so any suggestions would be appreciated. I then need to drill a multitude of 3/32" holes at 3/8" spacing for which I could stack them but what would be a reasonable thickness for the stack to ensure the holes do not run off. I believe a 90 degree drill point is recommended.

Hello Steve,

I don't know about the hole making, but I would sandwich the sheets, preferably individually, between scrap plywood or similar and run them through a vertical bandsaw with a wood cutting blade on it .

Others no doubt will come in with advice on the hole front

Regards

Brian

I should have mentioned sheet size is 1220 x 1220 mm and accuracy + or- 0.5mm required so I think it needs to be stationary whilst cutting. Would not the three teeth rule apply requiring a bandsaw blade of some 150 TPI?

Regards

Steve

Ah, not quite the size I had imagined. Any other oddities to be declared, while I think about the cutting again?

Regards

Brian

I would propose a sharp knife and metal straight edge. Cut over size and sand to finish size. How are you proposing to measure 1220mm to +/-0.5 ?

Cut oversize and use a router to trim either against a straightedge or if a lot to do make a template then use a bearing guided bit. It's not a lot different to Formica and other high pressure laminates.

Steve,

I think so much depends on what you have available in the way of wood working equipment. I am now thinking of a pull over circular saw on a guided arm so that you can cut across the sheet, with it clamped between two pieces of ply or chipboard. The sacrificial material could be confined to a broad strip covering the area in which the cut is to be made.

I think you would get away with a standard carbide tipped saw blade here as long as the cut isn't rushed. The paxolin will be prevented from chipping as the blade slices through the sandwich, but you need a big table or vertical sheet cutting facility to do a cut of that size; the rig would be like those you would find at the timber merchants where they do sheet cutting to size

Regards

Brian

May I ask if paxolin is a must as the material? If you could change to a modern thermoplastic (PVC, ABS, PC/ABS, PMMA or even HIPS) your life will be far easier machining the sheets.

Machining is an option but these thermoplastics could be punched as well. Punch tooling and a crude indexing system of stacked blocks against a fence could be made easily. Hard steel punches would not be required for 3/32" holes, unhardened drill rod punch and die would likely last for hundreds or thousands of holes before sharpening.

Just food for thought.

Score with a laminate cutter
https://www.stanleytools.com/products/hand-tools/knives-blades/multi-tool/534-in-laminate-scoring-knife/stht10192
or
https://www.amazon.co.uk/Rawlplug-89-040-Laminate-Cutter/dp/B0001P0MKW
snap over a edge and then square off with a sharp block plane.

I think we need to wait for the OP to clarify his question as some of the methods suggested probably don't apply.

Clamping the thin material (especially if its a stack of them) between sacrificial pieces is going to be tricky if the finished parts are the size of the full sheet of material, and that's before one contemplates what drilling machine has a 600mm throat!

Its unlikely that Steve wants to drill these with a pistol drill as he is already mentioned the drill drifting off if stacked.

I presume the 0.5mm tolerance relates to the parts after they have been cut out of the sheet.

Ian P

Tools for cutting Formica sheet should be suitable.

I would sandwich the sheet between plywood. Then I would have to decide what to use to cut it. My first choice would be mt tablesaw with the blade set as low as possible and still sever the sheet.

Second choice would be a mini-circular saw like this:

https://www.walmart.com/ip/Rockwell-Rk3440K-Versacut-4-0-Amp-Mini-Circular-Saw-Kit-With-Laser/20434561?athcpid=20434561&athpgid=athenaItemPage&athcgid=null&athznid=PWVUB&athieid=v0&athstid=CS020&athguid=ce537e76-f29-167d40feff1bd1&athena=true

Third choice would be my bandsaw. Probable with a 12 -14 tpi blade

At that sort of accuracy I would get it laser cut including the holes. I can suggest a suitable supplier if the OP wants.

Dave

As previously mentioned the sheet is 1220 x 1220 mm. I will use 20 thou material if I can get it otherwise 32 thou which I can get locally. Some thin plastics are 5 times the price of paxolin. I need to cut strips off it 1220 mm long and various widths,the widest being 104 mm and the narrowest 46 mm..

I could then stack to cut these long strips or cut individually to give widths between 65 and 141 mm. I would then have a number of rectangular pieces the smallest being 65 x 65 and the largest 104 x 141 mm.

The pieces then need 3/32" holes in them. The largest piece would have 165 holes 3/8" apart in all directions but only 1/8" from from the edge.. This is not a commercial operation and I have only one sheet to do. As regards a different material it needs stiffness and many plastics do not seem to be available so thin and surely blow moulding plastics would be floppy.

I do know the originals were punched way back in the 1930s of which I have no experience (thats both punching and the 1930s). Would a flat ended 3/32" silver steel punch work or would it need to be hollowed out to give an edge? If I make a steel plate with all the holes in I would then perhaps have the option of drilling or punching one hole at a time. I suspect though that whilst a could drill a few at once in a stack they would have to be punched one piece at a time. I suspect also for punching I would also need a guide plate top and bottom.

Laser cutting and drilling sounds interesting but I expect prohibitively expensive

I will send a further post if I can with a scan of the finished product but I need to shut down my computer before I can fire up my Scusi scanner

Thank you all

Regards Steve

Good quality masking tape will help prevent microchipping at the edges.

Recommend flat punches for simplicity of sharpening. However. if you have capability to grind two angles about 20 degrees each, from OD to centre, to make a tent shaped end on the punch, this will cut progressively and take much less force. If these parts were punched originally in various sizes, the makers may have had various fence-type dies operating on a base plate with stops or pins at the various hole positions. If you should want to make square nuts with one hole, you only need a width guide each side and an end stop on a lever. The stock is advanced to the stop, hole is punched, stop is retracted to push the part out the back. Stock is pulled back, stop reset inward, repeat process. Before long you have a big bin of nuts.

As late as the 1990's the firm I used to work for had hand feed dies like this for heavy brass parts with multiple holes. The stock would come cut into strips on a long wood case and be picked up and fed by one of a pair of very tough and strong older ladies who had worked at the firm since WW2. Great people doing a tough job. The job was done this way because the heavy brass was either not available on large coil for feeding to an automatic press, or there was a tight flatness spec on them that coiled stock would not be able to be flattened to.

Steve

I do not know what your budget is bu.t Laser cutting is not prohibitive. Have a chat with Tim here:

https://www.timhorn.co.uk

He makes baseboards for modelrailways and has a suitable size and type of laser cutter. He does one off jobs as well.

Dave