How to drill at an angle without angle vise

[Inferno]

You mentioned production and repeats so a little time on a fixture might be worth it. My approach would be to do the profile and mounting holes first and save the angled holes until your last operation. I mocked up my approach for you in a way that could be all manually machined. The angle could be simply laid out with scribes and referenced in the vise for the fixture block machining. The holes on your finished part are used fasten the part in place which is located by one ledge and the dowel pin.

-Nick

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You have a really good illustration of what I'm trying to do and the jig looks like it would be a good way to go.

Production?

Make a fixture that the part bolts to that holds it in the correct position.

Fixture can be just a chunk of metal large enough for your vice to hold with the top at an angle that would allow the needed work to be vertical.

Your part has mounting holes so easy.

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I'm having the blanks waterjet cut so I can't leave them rectangle but there's 2 parallel edges to start with.
The fixture method might be the way to go. I have a bunch of starter blocks I could make a jig from. I'd just need to mill a 30ᴼ face to get it on the right track.

 

[GT-6 Racer]

You have a really good illustration of what I'm trying to do and the jig looks like it would be a good way to go.



I'm having the blanks waterjet cut so I can't leave them rectangle but there's 2 parallel edges to start with.
The fixture method might be the way to go. I have a bunch of starter blocks I could make a jig from. I'd just need to mill a 30ᴼ face to get it on the right track.

If making more than 1 or two a fixture is a necessity. Well worth the time

 

[gard]

If you are only making a couple and machining aluminum you could probably use hardwood for the fixture, Nuts, bolts and a plate or big washers on the back. The fixture can be made to a size that will fit in your vise or clamped to the table.

 

[MikeInOr]

If you are only making a couple and machining aluminum you could probably use hardwood for the fixture, Nuts, bolts and a plate or big washers on the back. The fixture can be made to a size that will fit in your vise or clamped to the table.

This is what I was also thinking. Set the miter saw to 30 degrees to make the angled face on the hard wood jig.

When the initial post said a 30 degree hole I has envisioned a 60 degree hole. It seems like you would have to carve out a flat 60 degree indent with an end mill to drill an accurate 30 degree hole (90 degrees from the milled out flat) without the drill bit walking?

With a metal blade a stiff (usually non-sliding) miter saw can cut a good surface on a block of aluminum if you want an aluminum fixture. I would go for hardwood though if it will only be used a couple of times. (The sliding miter saws I have used usually have too much deflection in the slide to get a good surface).

 

[Inferno]

See? That's why we ask questions.
I don't need "exactly" 30 degrees. And I have a miter saw and I'm not afraid to cut aluminum with it.
If I can get the aluminum block to sit in it safely (had a few mishaps with that saw) then I can just cut the 30 degree face on the miter saw.
I'm going to start with 24 blanks and hope to get 20 good ones finished.

Great idea, guys.

 

[Batmanacw]

I don't know if it's been mentioned but a grinding vise in a Kurt vise is a super easy way to hold a part at an angle. I've done it lots.

 

[tq60]

Wood MAY be okay for a couple.

Use your idea to cut wood to hold the blank for your fixture.

Make the fixture from aluminum or lean block.

Also make a drill guide, even with tight table and DRO, the holes in production mode may not align.

Production means fast repeatable actions.

Start with a top plate, but cut 2 and stack them, get the holes drilled in exact placement.

Drill to tap size for your bolt.

Before moving to second hole, drill partway through top one with bolt size drill.

Needs to have way to positively align with blank.

Split the plates and finish the bolt hole in the top.

The bottom one is your guide for drilling the bolt holes in your fixture.

This insures every one is exactly same.




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[MikeInOr]

See? That's why we ask questions.
I don't need "exactly" 30 degrees. And I have a miter saw and I'm not afraid to cut aluminum with it.
If I can get the aluminum block to sit in it safely (had a few mishaps with that saw) then I can just cut the 30 degree face on the miter saw.
I'm going to start with 24 blanks and hope to get 20 good ones finished.

Great idea, guys.

I am happy to hear that you figured out how you will proceed....

So, what is it? What is it for?

 

[Charles scozzari]

Why can't you shim it right off the mill table to the degree you need, working off blocks to avoid drilling into the table.

 

[Inferno]

Why can't you shim it right off the mill table to the degree you need, working off blocks to avoid drilling into the table.

I don't have a ton of tooling to do shims and such.

I am happy to hear that you figured out how you will proceed....

So, what is it? What is it for?

It's an injector holder for a 50 year old injection system.
I could use the stock injectors but with an aftermarket controller (Megasquirt), I have a lot of options for injectors. The stock injectors are getting more and more rare but I can pick up newer injectors for a fraction of the price. And if one goes bad, they're cheap to replace.

There's no off-the-shelf alternative to the stock injectors and no off-the-shelf injector plate for a more modern version.