Right......... I have a small penny washer 50mm with a 6mm hole in the centre. I want to mark out a small equal sided and equal angled triangle in the centre, the points of the triangle will be drilled with a 6mm drill bit, each point is to be 10mm from the outer edge of the washer, Hows the best way to mark the points ? or work out the size of the triangle ? thanks
I think you'd mark a 'T' on the washer, thus: Draw a line across the centre of the washer, that's your 'T' upright. Mark 10mm down the upright(that is NOT your first point). Mark a line perpendicular, so square across that 10mm mark. You have your 'T'. Your three points will be 10mm 'UP' the upright, and the other 2 will be in a line throught the centre hole where your perpendicular line is 10mm from the outer edge. Check lengths of sides(all equal) OK. Now that sounds more complicated than it really is. Mr. Handyandy - really
Try this, Use a compass to draw a circle. Leave the compass set at the same radius, place the point anywhere on the circle and strike an arc on the line further round the circle, move the point of the compass to that position and strike another arc, move around the circle and with a bit of practice you should be accurate enough for the last arc to be on the original point. You now have six evenly spaced points, use three of them joined up with a ruler to form your triangle. You should be able to make a template by drawing your 50mm circle, then another 10mm in from that. Draw your triangle on the inner one, as above and use it to mark through to your washer. Please let us know what method you use and how you get on. Good luck, hope it helps.
To get an equalateral triangle. Mark a straight line on your carboard etc. Judging by what you have said it should be 30mm ( 50mm less 10 x 2 )..Set dividers at 30mm and scribe from one end of your line an arc, then scribe from the other end another arc then crosses the first one. That is now your datum for the equal triangle. Join these 3 points together. You have your triangle. Now you want 6mm holes at these points. Transfer onto your washer the triangle central. Now drill your 6mm holes on the washer and then draw your cut lines on your washer across each of the drilled arcs. That will be your required finished job. Hope that helps as difficult to explain, but that will do it. Regards
Or another way. Stick washer to piece of card etc. From centre scribe a 30mm dia circle. Adjust dividers and scribe around circumference edge of the 30mm circle until they go from one to the next in 3 equal divisions. That is your triangle. As before drill your 6mm holes at these points and join across the arcs for youe finished cut out. Regards
equal sided and equal angled triangle in the centre Surely an equal angled triangle will be equal sided? IWS: Information With a Smile
Clamp to your milling machine tabel Find center with an optical edge finder Set DRO to zero Get out Zuez tables and find settings for three holes on PCD. Calculate co-ordinates for each hole Put spot or center drill in chuck and spot each centre Well you did ask for the BEST way!! Should get you accurate to 0.001" Jason
Clamp to your milling machine table Find centre with an optical edge finder Set Digital Read Out to zero Get out Zuez tables and find settings for three holes on a Pitch Circle Diameter. Calculate co-ordinates for each hole Put spot or centre drill in chuck and spot each centre Well you did ask for the BEST way!! Should get you accurate to 0.001" it's even easier to use a magnetic chuck on the machine table but it's only easy if you have the equipment in the first place - which I doubt he has IWS: Information With a Smile
Here's an easier way. You will need a piece of string the exact length of the circumference of a 30mm circle(that circle that would pass through your 10mm points on your 50mm washer. So wind the string round a 30mm washer or whatever, and cut it at exact length. Straighten it out. Measure it, mark it at one third and two thirds distance. Wind it back round the 30mm washer and join the dots(or just mark the 30mm washer with dots. One triangle. Place the washer on to the 50mm washer 10mm in central. mark the dots. Allow for thickness of marker(or use sharp points when marking. Mr. Handyandy - really
Draw a line on a bit of ply. Drill a small hole the diameter of a pin tack 10mm from the edge of the washer. Nail the washer loosly to the ply on the line. Now move the washer until the line is along the diameter. Mark the washer and remove it. Stick compasses where the washer was pinned and draw an arc crossing the line. Now with the same radius on the compasses, centered on the point where the arc crosses the line, set off the radius on the arc. You can now draw a line 60 degrees from the first line centered on the pin point. Replace the washer with the mark on the first line. You can now mark the second line, turn the washer over and mark the third. Now all you have to do is to measure 10mm from the edge to centre the other two holes.
scribe a line through centre of hole (centre finder in combination square set) Centre punch where first hole to be Scribe from this mark down a 30 degree angle on both sides of first line.with a 60 degree set square slide down line until same distance from outside edge as first mark then scribe across to other line centre punch where this line crosses other two
You'll need to find the centre too work from, tape the washer down then mark the centre. Use dividers or compass to mark the PCD of the centre of the holes. Mark a point anywhere on the marked circle, then use dividers to well, divide it into 3 equal parts on the circle. Centre punch and drill.