Angle Plates and Fixings

[Mike DonnerstagParticipant @mikedonnerstag]

I have two angle plates – a little Myford one (3" x 2" x 1.5&quot and a much bigger one (6" x 5" x 4.5&quot. Both are cast iron and neither have webs. The casting thickness of the large on is 1". Both have one face slotted but the other face plain.

My question is: Is there any advantage to having a plain face on an angle plate, i.e. without any fixing holes or slots? Or… are these made with a plain face for drilling to suit the machine on which it will be used? The reason I am asking is that I am considering drilling the larger plate to suit my Sieg SX3 mill table.

Many thanks,
Mike

[Mike DonnerstagParticipant @mikedonnerstag]

[peak4Participant @peak4]

I'd suggest it's broadly useful to have a flat side as you can scrape it even more flat and use it for checking other parts with some Micrometer Blue.
That of course doesn't preclude you drilling and/or tapping, as appropriate, for other fixings as well.

Bill

[David George 1Participant @davidgeorge1]

Hi Mike I have a pair of angle plates one side has a few slots and the other has a series of tapped holes. They are about 5 inch by 6inch by half inch section. They are square on all sides and ends so I can clamp or screw a part to it and if I for instance turn the angle plate on its end the part screwed to it will still be square to other plane so you can mill or drill in either plane and they will be square.

David

[Mike DonnerstagParticipant @mikedonnerstag]

Thanks you two.

David: That angle plate has plenty of holes! That gives me some confidence to drill mine!

Mike

[HOWARDTParticipant @howardt]

Slotted ones or any form of holes are primarily used for building up work holding on one off or small batch machining. Solid forms may be used for the same but are often used in high volume fixturing. Accurate ones may be used for inspection. As model engineers we use what we have for anything. I have a couple of solid webbed 75mm angle plates and they do all the above.

[old martParticipant @oldmart]

You could use clamps to hold down the plain side of the plates to the mill bed, but having some holes at the right pitch to suit the tee slots would do no harm to the plate and be more secure. If you have 10 mm studs for your tee slots, then drill the holes a little larger, say 12mm. Deburr the edges on both sides of the holes. Depending on the width of your mill bed, the hole spacing could be made to fit the plates either way round.

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