Help milling an angle

I'm wanting to get a 60 degree angle on a piece of 1/4” steel like this....

The steel is 1/4” thick, 6” long, 2” wide. The angle is along the 6” edge.

I don’t have any angle plates but have a digital inclinometer. I don’t think it’s critical that the angle is precise.

The vice on my mill will open to a bit more than 4”

I'm unsure of the best way to clamp plate.

The head on my mill does tilt, but only to 45 degrees x axis. It will tilt to 60 degrees y axis but the vice won’t open wide enough to take steel that way. I guess I could clamp steel to the bed, but am wondering if there is a better way?

30 only need to tilt head 30deg for each side. Turn the vice so jaws run front to back. mount work edge up and use Y axis to cut using side of a milling cutter.

Or clamp to table with work in y axis and use end of tool.

Your 60 degrees angle is two 30 degree angles so all you have to do is clamp the plate down flat on the table (on stand-offs) and nod the head 30 degrees, do one side then flip the plate over. I like to use scrap 1/2" MDF for this kind of thing, lay the MDF on the bed, plate on top, couple of clamps and you know you can mill away without milling the table.

Double-post..

Edited By Pete Rimmer on 28/08/2019 11:03:37

Clamping material to the bed IS the better way.

Unless the job can overhang the edge of the table (and be reachable by the cutter) you will need packing underneath your workpiece.

Ian P

Now I know how long it take me to type compared with others

Edited By Ian P on 28/08/2019 11:06:41

You have said that the 60 degree angle is not critical.

Mark out the shape on the plate and rough cut (slightly larger) with a thin blade in an angle grinder. Then clamp it on top of the mill table with a spacer under the plate and finish the edge of the plade with the side of the milling cutter (The side cutting surfaces of the cutter are not normally used as much as the end and and this is an oportunity to save it for an end milling operation )

Re-clamp the plate end finish the other edges.

Paul.

(PS. You have to type quickly on this site)

Edited By Paul Lousick on 28/08/2019 11:11:36

N.B. I haven't got a pencil out to draw this to check my initial thoughts;

How about obtaining a length of large hexagon bar, clamp to either an angle plate, or a length of square bar, such that the pointy bit of the hex is to the top. This can be along the length of the milling table.

Then clamp workpiece to one angle of the hex. Mill a flat on the edge, half way through, and turn over to mill the other side of the 1/4" plate. The included angle should be 60º

Have I had enough coffee to think this through correctly?

Bill

I dont understand the question. Are you making a flat plate identical to the drawing with a 60 degree angle?

Or are you making a flat plate with angled long edges? Your post is not clear hence the confusion.

If it's the former, rough it out with a saw and finish with files or a belt grinder. There is no need to waste time on a milling machine when it could be done much more quickly as I suggest.

Regards plasma

After reading your comment, I just cheated and went to Grotto's album, called "Brake", so I guess a 6" long plate with a 60º included angle along one edge to form the blade for a sheet metal bending tool.
I was actually thinking about making one yesterday, hence I'd already pondered on a workholding method, then subsequently read the thread about 13 useful items for the workshop.

Bill

Edited By peak4 on 28/08/2019 20:28:32

Peak4 wrote

After reading your comment, I just cheated and went to Grotto's album, called "Brake", so I guess a 6" long plate with a 60º included angle along one edge to form the blade for a sheet metal bending tool.
I was actually thinking about making one yesterday, hence I'd already pondered on a workholding method, then subsequently read the thread about 13 useful items for the workshop.

The light really shone bright when you down load the whole set of vice brake drawings that Michael Gilligan provided the link to.
Grotto,
Are you going to split the 6" length into 3 pieces as per Jonathan Maes design? Having them split and moveable will, I think, make the brake more flexible to use.

Bob D

Thanks for all the suggestions.

Hopefully I'll get some time today to have a go.

Bob - I will split the 6” length into 3 pieces, but thought it easier to mill the angle on one length to make sure angle is consistent and only have to set it up once.

will let you know how I go.

Found some time today so set up the steel plate to mill the angle.

Sorry - don’t know how to rotate photos!

I used the side of a end mill I'd previously destroyed the end of - side was still as new so got a nice finish.

I did one side, then rotated work piece and started the other side. Soon discovered the vice was not 100% square - got a ten thou. flat at one end but 25 thou. at the other. Squared the vice and redid both sides and it turned out perfect (a novelty for me).

I've got a foot long bar of cast iron which I'll use for the other parts, as I don’t have any steel the correct size. So far I've just cut it into two 6” lengths after face milling the rough side.

Edited By Neil Wyatt on 29/08/2019 09:54:28

Please beware that cast iron has very little tensile strength - I think it's possible that it will split along the base of the "V" if put under too much pressure - other opinions?

.

+1

... but success or failure will probably depend upon the stiffness of the material being folded.

MichaelG.

Thanks for the advice. I think I knew that but hadn’t thought about the need for tensile strength.

I'll go ahead with the cast iron as it’s all I’ve got on hand other than some aluminium alloy which is probably a bit soft. I’m only planning on folding thin sheet (3mm max) initially, and if it splits I'll chalk it up to experience.

Interesting that you think 3mm sheet is 'thin'

I reckon you're going to struggle bending it with the design you're building, which does work well on the 0.8mm I use for most car bodywork repairs. Your vice won't 3mm either!

Oops!

not sure where the 3 came from, it was meant to be 1 mm max. I need a bigger phone or smaller fingers

most use will be on 1/2 mm copper but good to know it will handle 0.8mm

Well I finished it off. Just need to trim the punch holder to length.

works well on 1.6mm copper. I guess time will tell if it splits, but I didn’t have to put much pressure on it to fold the sheet, so I’m hoping not

Just an observation Grotto but the endmill you used to cut the angle on the 1/4" steel looks to be no more than a 1/4"/6mm size plus with the work mounted as it was meant the tool was cutting close down towards the tip. I am not criticising and it worked but I think it would be better and safer to go with a larger stiffer tool, say 10mm or the like in that situation.

As I say just an observation.

Edited By Ron Laden on 01/09/2019 09:20:40

Well done - I think if the action feels easy, then the CI will be fine, and I'm happy to eat my words! It's always satisfying to complete a bit of tooling that gives good results.