Machining tapered shafts w/ conical endmill/horizontal rotary table

D

Dilettantism101

Plastic

Joined

Oct 24, 2021

• Nov 17, 2021

• #1

Hello,
I am devising a method for machining 8 deg. tapers into 1/2 ground dowel pins... on a mill.
Currently, my idea is to mount a 5C rotary indexer in the vertical position on the table and use a conical
endmill to take incremental passes into the taper while continuously rotating the part.

Is this a reasonable method? I need these pins to be as concentric as possible and unfortunately can't find anything off the shelf. Any other more precise methods, omitting a lathe?

 

johnoder

Diamond

Joined

Jul 16, 2004

Location

Houston, TX USA

• Nov 17, 2021

• #2

Might want to check machineability if these are commercial off the shelf dowels which are quite hard

 

D

Dilettantism101

Plastic

Joined

Oct 24, 2021

• Nov 17, 2021

• #3

1144 heat treated 48-55RC. They're from Carr Lane. Would a carbide AlTiN coated 3fl em be a match for this?

 

G

GregSY

Diamond

Joined

Jan 1, 2005

Location

Houston

• Nov 17, 2021

• #4

Your plan sounds good, as long as there is no requirement for a good finish or accuracy. The first problem will be your hand-rotated table will produce varying amounts of cut. Then, the tapered end mill will also not give a repeatable cut, especially in a fairly hard material. It will also give a varying finish the more you increase the contact area.

It's a mess, all around, unless you have a very loose requirement of finished product.

 

D

Dilettantism101

Plastic

Joined

Oct 24, 2021

• Nov 17, 2021

• #5

The rotary table is CNC controlled, but fair points. The material removal is minimal, I was thinking take a few thou passes per rotation and then a couple of rotations at final depth as a spring pass.

 

crossthread

Titanium

Joined

Aug 5, 2004

Location

Richmond,VA,USA

• Nov 17, 2021

• #6

It might be better to tilt the rotab and grind the pins with a dressed cup wheel. The fact that you don't have a lathe limits your options somewhat. Not saying it can't be done, it's just going to be interesting.

 

D Nelson

Stainless

Joined

Jan 7, 2015

Location

Missouri Ida

• Nov 17, 2021

• #7

If it’s cnc just surface it with a ball Endmill
Don


Sent from my iPhone using Tapatalk Pro

 

H

howieranger

Aluminum

Joined

Jan 24, 2007

Location

Mountain Home AR.

• Nov 17, 2021

• #8

Is your mill like a BP that you can tilt to the head to proper angle and mount the workpiece in a collet? Then you can mount a carbide tool in the vise and raise the table up and down for the cut using the x or y for depth of cut or advance the quill into the tool.

 

M

memphisjed

Titanium

Joined

Jan 21, 2019

Location

Memphis

• Nov 18, 2021

• #9

Put pin in the spindle and have cutter mounted on table. No rotary needed.

 

eKretz

Diamond; Mod Squad

Joined

Mar 27, 2005

Location

Northwest Indiana, USA

• Nov 18, 2021

• #10

Got a surface or tool/cutter grinder? I'd spin grind 'em.

 

S

stephen thomas

Diamond

Joined

Jun 3, 2001

Location

downhill from Twain\'s study outside Elmira, NY

• Nov 18, 2021

• #11

Memphis nailed it. (using your angled cutter; or angling a straight cutter)

However, that does put a lot of edge pressure (deflection) on both the tool and work.

Even better would be if you have a small slide, that can angle to what you need, and use it in conjunction with the mill spindle as an ad-hoc lathe. using carbide tip single point bit.

As mentioned by others, spinning on a surface grinder would be easier/faster/better.

If you want esoteric mill methods, use a taper-boring, boring head.
Although i sometimes taper bore seats on the mill with a taper boring head, i usually make the mating part in a lathe or on the surface grinder. Example shown was for "demonstration purposes"

Good luck!
smt