Thread: Marking triangles

Thank you Niki.

However can I set you a task?

I want a straight edge around 1 metre long, that is accurage to .000.
and can be used to check out things like my thicknesser tables.

Suddenly thought of an idea myself. how about a length of taut string stretched to a nail each end of a batten and looking like a bow saw.

Thank you DW

Yes, it's a great idea but I think that it's better if the string will pass below the sticks so when you put it down on the table, it will be at the same level.

Regards
niki
Attachment 59201

That will highlight depressions but may not show up bump to the accuracy you want as the string could deflect slightly without you knowing. Even depressions might be hard to spot the relative fuzziness of string. Or am I missing something.

Pusser

OK Pusser, so we need a new idea.

Any takers?

shame you couldnt tie a string between the bottom string and the centre as this would droop'/slacken off if there was any depression.

If the string and holding setup was longer than the piece being tested it would make both discreptancies stand out. ?

Originally Posted by jow104

OK Pusser, so we need a new idea.

Any takers?

Sorry to be negative but my solution was to buy a 1 metre strait edge and some feeler guages.

When I used a triton i used a laser pointer with a series of targets on a wooden base and just jacked up the adjustable legs until the laser passed through the holes in the centre. It was ok but is an alignment test rather than a flatness test. The accuracy required which I interpreted to be better than 0.0004mm is tough even with a straight edge. Trying to sight a gap under string would be a tough ask and a few thou bend in the string is going to be nigh on impossible to see.

Pusser

Sorry Pusser no spending allowed.

I use my 1 meter level as a straight edge didn't buy it.... it's been around for years
les

Les, I also have got a 1 metre ruler, reasonable quality, but it sags, drops down at the ends to take a rest.

So when I lay it across the P/T it gives me a true reading which I suspect is false.

Looks good. But just quietly, I reakon you should grind a plough blade to plane a trench that gives you a tight fit for those set squares.....say 3-5mm deep then slot them in with that glue. But thats just an opinion. Be other ways too I'm guessing.

Thank you Apricotripper

I did it on two of my triangles but for some reason, after some time the setting (squareness) changed...maybe because I used Pine as a base...

Later, I thought that it's too much work to make the base very consistent in width (so I'll get square from the inner and the outer side of the base) and to make the slot on the router table so, I thought that plywood, MDF or "floor panel" are very flat and consistent in thickness and gluing it with CA (super glue) will be strong enough.

The plywood triangles are 6 mm thick that I made 2 months ago and nothing broke or changed.
Yesterday I tried to break the plastic one and it looks very strong...

Regards
niki
Attachment 59364

Why not just laminate a slat on each side of the triangle, so the plastic edges are still the references?

That way, any variation in the wood thickness shouldn't affect the angle.

I hope niki doesn't mind me hijacking into his thread again but what Skew has written could apply to my steel 1 mtr. ruler. I could laminate a piece of ply to the steel to reduce zagging?