What's new
What's new
By:
Advanced search…

Speed/Feed for Carbide Center Drill

C

cosmos_275

Hot Rolled
Joined
Jun 9, 2015
I've been breaking drill mill tools when spotting holes. HSM advisor seemed to keep slowing me down, but maybe I'm using the program wrong. I think the SFM is based on the largest diameter of the tool, which doesn't help if I'm making a small spot drill. It threw up a tool torque warning, so I was slowing down feed and speed, but I think it made things worse. I'm switching to dedicated center drill 1/4" carbide.

Can anyone lend some advice on feeds and speeds? I've searched and found some good tips but I'm assuming they are for HSS.

.005" per rev sound reasonable for AL, mild steel, and stainless?

RPM, 10k (my machine max) in AL? 5K mild steel, 1k stainless?

I broke a couple on mild steel and stainless recently. I was well under 1k RPM if I remember. I think I was going to slow on feed also.

Advice appreciated.
 
Use a spot drill for spotting holes, not a center drill. A center drill's point is relatively thick across the web, which doesn't give much flute space, and they will plug up fairly easily if used too aggressively without a pecking cycle. So then the small pilot is easily broken off.
 
CosmosK said:
I've been breaking drill mill tools when spotting holes. HSM advisor seemed to keep slowing me down, but maybe I'm using the program wrong. I think the SFM is based on the largest diameter of the tool, which doesn't help if I'm making a small spot drill. It threw up a tool torque warning, so I was slowing down feed and speed, but I think it made things worse. I'm switching to dedicated center drill 1/4" carbide.

Can anyone lend some advice on feeds and speeds? I've searched and found some good tips but I'm assuming they are for HSS.

.005" per rev sound reasonable for AL, mild steel, and stainless?

RPM, 10k (my machine max) in AL? 5K mild steel, 1k stainless?

I broke a couple on mild steel and stainless recently. I was well under 1k RPM if I remember. I think I was going to slow on feed also.

Advice appreciated.
Click to expand...

Drill-mill is actually a mill with 90 deg tip. It is not a drill at all and should not me used like that.

I recommend defining a chamfer tool and using the slotting plunge parameters for RPM and Feed rate. I am away from PC now. But (from my memory) 10k rpm and about 5-10ipm should be good.

Btw. Centerdrills really suck with stainless. Unlike normal drills they dont have web thinned and rub a lot.
 
Thanks both. I'm using a spot drill. My terminology is wrong. I use spot/center interchangeably and that is wrong. Thanks for clearing that up for me.
 
zero_divide said:
Drill-mill is actually a mill with 90 deg tip. It is not a drill at all and should not me used like that.

I recommend defining a chamfer tool and using the slotting plunge parameters for RPM and Feed rate. I am away from PC now. But (from my memory) 10k rpm and about 5-10ipm should be good.

Btw. Centerdrills really suck with stainless. Unlike normal drills they dont have web thinned and rub a lot.
Click to expand...

Yes, The drill mills are dead to me. They don't seem to drill well.

So, 304 SS and here is what the program gives me: 0.1 IPM feed. rub and break it seems

Don't get me wrong, I love your program. It has been awesome for me starting up a job shop and being new to a lot of materials. I'm just looking for some rules of thumb for spot drilling and not try to get the program to give me something it's not designed for. Thanks

hsm.jpg
 
You don't need to baby it just because it is stainless, if you can put coolant on it. The actual center point is turning at a very low SFM, so overspeeding that part of the tool is not a concern, but you're unlikely to slow it down as it gets deeper, so we go with the typical SFM recommendation for the drill and the material.

If you can run any HSS drill at 100 feet per minute, then the feed rate for all HSS drills is between 8ipm and 4 ipm. Maybe 4x faster for carbide, so from 32ipm to 16 ipm.

A spot drill is pretty sturdy, so it doesn't need a chicken shit feed. Maybe give it .1 sec dwell so the cone the tool leaves in the work is smooth.
 
Agree with others. Drill mills suck on stainless as a spotting drill. You can chamfer stainless with them but they will break if used to spot drill holes.

Use a hss spotting drill and save the drill mills for aluminum.
 
You must log in or register to reply here.

Similar threads

J
Stainless steel 316
2
Replies
20
Views
677
Houdini
Houdini
J
machining 304 stainless steel
2 3 4
Replies
67
Views
2K
dkmc
dkmc
A
1.125 spade drill thru titanium clad carbon steel
Replies
6
Views
294
Northman Ind.
N
S
Drilling speeds and feeds for tool steels D2, H13, O1, S7, W2
Replies
9
Views
368
Dan from Oakland
D
M
Haas lathe stops feeding when changing speed. Is there a parameter to change this?
Replies
10
Views
567
Ox
Ox








 

ABOUT PRACTICAL MACHINIST

With more than 10.6 million unique visitors over the last year, Practical Machinist is the most visited site for metalworking professionals. Practical Machinist is the easiest way to learn new techniques, get answers quickly and discuss common challenges with your peers. Register for the world’s largest manufacturing technology forum for free today to stay in the know.

Learn more about us.

STAY CONNECTED

Facebook Instagram YouTube LinkedIn Pinterest Twitter Tiktok

Register Become a forum member. Register today.

Sign Up Sign up for our e-newsletter.

© 2024 Copyright Practicalmachinist.com. All Rights reserved.

Back
Top