What is the best way to fixture this part for drilling an angled hole?

robert123 · Nov 13, 2020

So this steel part is around 1.75" across, 1.75" long, and has a .125" hole at a 15 degree angle (+/- 1 degree). The hole location is +/- .010" from the hex end. We need to make about 15 pieces. The plan is to make the part complete except for the hole on our lathe and then put it in a mill to cut the angled hole. What is the best way to hold the part at the 15 degree angle and locate the hole correctly? I'm not thrilled with any solutions we have come up with so far. I figure if I ask 100 machinists, I should get at least 100 ideas of the best way.

Mike1974 · Nov 13, 2020

A little work, but I would take a (larger than part size) block, tip it up 15deg with a sine bar, mill a flat, insert some locating features (pins/plugs/boss/etc). Mount part on fixture, locate in vise, may need to add a place for a tooling ball if hole position is close positional tolerance.

BoxcarPete · Nov 13, 2020

You don't have a tilting head manual mill? For a single hole with those tolerances on 15 semi-finished pieces, I don't see any reason not to just tilt the head on a Bridgeport.

Limy Sami · Nov 13, 2020

Vice on a tilting angle plate

Simple spigot and clamp again on a tilting angle plat or may a block milled to the angle

I make that about 95ish to go

Conrad Hoffman · Nov 13, 2020

You don't have a cheap angle block set that has a 15 degree block?

Scottl · Nov 13, 2020

I would think an insert vise mounted atop an angle block in the main vise and fitted with an end stop would be the easiest for a small quantity. The main issue I see is using something fairly rigid to spot the hole first before drilling. Because I'm in a home shop situation with limited tooling I'd probably use a carbide .125 end-cutting burr to start the hole.

If the issue is finding the start point of the hole on an angle mounted part, either a simple Trig calculation or drawing it in CAD would solve that.

GENERALDISARRAY · Nov 13, 2020

robert123 said:
So this steel part is around 1.75" across, 1.75" long, and has a .125" hole at a 15 degree angle (+/- 1 degree). The hole location is +/- .010" from the hex end. We need to make about 15 pieces. The plan is to make the part complete except for the hole on our lathe and then put it in a mill to cut the angled hole. What is the best way to hold the part at the 15 degree angle and locate the hole correctly? I'm not thrilled with any solutions we have come up with so far. I figure if I ask 100 machinists, I should get at least 100 ideas of the best way.

View attachment 304557

The plan is to make the part complete - on our lathe

EPAIII · Nov 13, 2020

I would use one of those "screwless" vises clamped at an angle in my milling vise. A 15° angle gauge would quickly set the angle so I would not have to disturb the tram of my mill. Then use a flat tipped milling cutter to create a flat or starting bore for the hole. A carbide milling cutter will not deflect when it first hits the angled surface.

A standard drill bit can be used to finish the hole to the proper diameter. Or, if it is a common diameter, the milling cutter can do the whole job.

Quick and easy. Worst part would be tool changes between the milling cutter and the drill bit.

jhearons · Nov 13, 2020

$10K live tool to make 1 hole on 15 pieces of a $5 part. Nice

EPAIII · Nov 13, 2020

His angle tolerance is +/- 1°. Any angle setting device will be that accurate. He could use a $0.10, dime store protractor.

But an angle block would be the fastest way.

As for locating the hole, his print does not show any dimensions or tolerances so that would be somewhat difficult to answer. I would probably make a LIGHT punch mark on the part AND use a wiggler style center finder. If the part were located in the vise with a stop or just by the fixed jaw of the larger, milling vise then this would only be done one time.

But any tolerances that must be met would dictate the exact method to be used.

Conrad Hoffman said:
You don't have a cheap angle block set that has a 15 degree block?

robert123 · Nov 14, 2020

EPAIII said:
I would use one of those "screwless" vises clamped at an angle in my milling vise. A 15° angle gauge would quickly set the angle so I would not have to disturb the tram of my mill. Then use a flat tipped milling cutter to create a flat or starting bore for the hole. A carbide milling cutter will not deflect when it first hits the angled surface.

A standard drill bit can be used to finish the hole to the proper diameter. Or, if it is a common diameter, the milling cutter can do the whole job.

Quick and easy. Worst part would be tool changes between the milling cutter and the drill bit.

Thank you everyone for the ideas. I like this way (basically the same as scottl suggested as well). I think it will work without too much difficulty. It is a .125" hole so we'll probably just plunge an end mill all the way through nice and slow since it's not many parts.

robert123 · Nov 14, 2020

And I do like the adjustable angle live tool but certainly not worth the investment for this small job.

jscpm · Nov 15, 2020

No need to use a mill.

Mount a 1/8" bushing in a tool holder on the lathe. Set the compound to the required angle.

Use a hand drill drill with an extension to rough the hole, then use a reamer if a high-quality hole is desired.

upthebikes · Nov 15, 2020

jscpm said:
No need to use a mill.

Mount a 1/8" bushing in a tool holder on the lathe. Set the compound to the required angle.

Use a hand drill drill with an extension to rough the hole, then use a reamer if a high-quality hole is desired.

This is how I have done it. I have a 5c collet block for my tool post, and I made a 1” bronze bearing bored to fit a shop made drill extension sleeve. Drill bushing would be better but of course I did not have one lying around when I needed to do this task.

neilho · Nov 15, 2020

A slick setup would be a 3 jaw chuck on a Kalamazoo tilting 5C fixture, held in the vise.

Lacking ownership of said fixture, the 15 deg angle block works. 2 of them, double sticky taped to each jaw with a stop.

Search

Largest Manufacturing Technology Community on the Web

Search

What is the best way to fixture this part for drilling an angled hole?

robert123

Stainless

Mike1974

Diamond

BoxcarPete

Stainless

Limy Sami

Diamond

Conrad Hoffman

Diamond

Scottl

Diamond

GENERALDISARRAY

Hot Rolled

EPAIII

Diamond

jhearons

Cast Iron

EPAIII

Diamond

robert123

Stainless

robert123

Stainless

jscpm

Titanium

upthebikes

Cast Iron

neilho

Titanium

Similar threads