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poor end mill life

dgfoster

Diamond
Joined
Jun 14, 2008
Location
Bellingham, WA
Gard,

Your punch and measure the divot idea is used on some commercial hardness testers. If I were going to try to shop-make such a device to get a rough idea of hardness, I’d start with one of those spring-loaded center punches. It would provide a pretty repeatable impact. You’d need to experiment with the cone shape of the end. I’d start with a 120 included angle. Use one of those 5 dollar 45x pocket microscopes to measure the crater. I think you could distinguish Rc10 from 25 and 25 from 45 etc pretty reliably if you worked at it. I use both Leeb and Wilson testers and can see relative indentation sizes differences with the naked eye. Magnification and a fine scale will give you some ball park info. If you do this, post results here.

Send me coupons of samples and I will do more formal tests for you gratis to help you get started.

Denis
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
LOL I do not think I will use those exact words. The shop is in the basement and the only time I get grief is when she comes down to get something out of the freezer or root cellar. To be honest there have been a couple of times when the smoke from the oil is probably not very healthy. In the future I will change the cutter, slow down the speed and get some of the rustlick WS 5050. Looks like the smallest amount I can buy is 1 gal, that will last me the rest of my life plus some. Sometimes I don't even notice the smoke in the room until I look up from what I am doing, I kind of like the smell.

Sorry about the typo, it is 0.5" cutter at 600 RPM, I would never try a 1.5" cutter on steel at that RPM.

In the original photo, I started the cut on the left side, about 1/8 thick steel. You can see a flux inclusion where that bar was welded to the shaft section. In hindsight, the bit worked very well on the first section then suddenly went dull about where it hit that inclusion it was also about where it went from cutting 1/8" wide to the full 1/2" wide so that seemed the cause at the time.

Most of what I do is one of a kind tools or repair work, speed is not a top priority.

I have often wondered about a way to measure hardness of steel, are there any small simple tools for this? I was also thinking of using a spring loaded center punch then trying to measure the diameter or depth of the divot and comparing that to some known samples. Perhaps a 0.0001" indicator with a pointed tip. I am sure there must be someplace I can get some known steel samples.

Install a small blower (rob a clothes dryer for a good one) outside under the eaves, plumb some 4" PVC thin wall to the machine to remove the offending smoke. Putting the blower outside makes all the plumbing inside suction only, so leakage is not a problem.
 

Gard

Aluminum
Joined
Mar 18, 2016
That's a good idea to bring the exhaust closer to the tool, sort of like the sawdust vacuum systems. Currently I have a variable fan in a window that does an OK job of keeping smells in the basement and helps with clearing out the smoke.

I will have to see what I have around or can buy that for a microscope that will measure punch mark width. The ones I used years ago at work had cross hare in the scope and a calibrated X-Y table. Also accurate depth measurements at high mag using focus. Thanks for the offer of testing.

For a part like this I should of dragged out the MIG welder with gas. I reached for the stick welder because it was right there. I should of known that with this geometry, some slag inclusion was almost guaranteed. I would love to get a TIG system and learn how to use it, its on the list.
As is often the case this project design changed some during the building and testing phase. At first it was going to be, just tac weld these arms to a rod, then drill the center hole. In fitting it I realized I needed to reduce the height by 0.1" so then it went back onto the mill.
 

jim rozen

Diamond
Joined
Feb 26, 2004
Location
peekskill, NY
Unless you are operating your mill in the bedroom, your wife has no business complaining about the smoke. Look her in the eye and simply say those four words every woman needs to hear from time to time - 'less bitchin', more kitchen...'


I'll give you a hundred dollars cash to come to my house and say that to ms. mulligan. As long as I can film what ensues.

Mulligan.jpg
 

BT Fabrication

Stainless
Joined
Nov 3, 2019
I have a Clausing mill cutting what seems to be a fairly mild steel, it files and cuts with a hacksaw easily but I do not have a hardness tester. This is a simple one of a kind weldment, depth of cut was 0.1", 1/2" end mill at 600 RPM dry manual feed. The new end mill seemed to cut well until I got to the welded area then suddenly got dull about as the width of cut went from 1/8" to full 1/2". The end mill was brand new double ended 4 flute uncoated HSS Hertel. It seemed like a great price $18.99 for double ended end mil from MSC, WW41117607. I thought Hertel was a good name, these were made in Korea. The end mills seem to have a fairly sharp corner.

So what should I do differently?
Thanks

View attachment 344951

600 RPM! too fast....
 

rrrgcy

Aluminum
Joined
Jun 5, 2013
Location
South Florida
Another option for hardness testing - From the biggest file manufacturer in Japan by way of the Kure district of Hiroshima, you can search for and get a six-piece set from the "TSUBOSAN MA00600" (japanese files) which test hardness range 40-65Rc. Interestingly I read there are 49 other companies making files in that district but Tsubosan has 95% national market share. Gotta suck to not be Tsubosan - you think you got problems making coin. The district was home to the naval arsenal that built the Yamato battleship in WW2.

I'll give you a hundred dollars cash to come to my house and say that to ms. mulligan. As long as I can film what ensues.

Tsubosan do make surgical files that shape and smooth bone.
 

projectnut

Stainless
Joined
Mar 4, 2006
Location
Wisconsin
That's a good idea to bring the exhaust closer to the tool, sort of like the sawdust vacuum systems. Currently I have a variable fan in a window that does an OK job of keeping smells in the basement and helps with clearing out the smoke.

I will have to see what I have around or can buy that for a microscope that will measure punch mark width. The ones I used years ago at work had cross hare in the scope and a calibrated X-Y table. Also accurate depth measurements at high mag using focus. Thanks for the offer of testing.

For a part like this I should of dragged out the MIG welder with gas. I reached for the stick welder because it was right there. I should of known that with this geometry, some slag inclusion was almost guaranteed. I would love to get a TIG system and learn how to use it, its on the list.
As is often the case this project design changed some during the building and testing phase. At first it was going to be, just tac weld these arms to a rod, then drill the center hole. In fitting it I realized I needed to reduce the height by 0.1" so then it went back onto the mill.

You might want to consider an inline exhaust fan with an inlet port over each machine. I put one like this in with an inlet over each machine. The smoke goes right up the duct and outside. I installed and wired it in an afternoon.

FANTECH Galvanized Steel Exhaust Fan Kit, Fits Duct Dia. 6 in, Voltage 120V - 3NYJ1'|'PB370-2 - Grainger

As for end mills they've been pretty well covered. Some time ago I had a job that needed similar radiusing on weldments. I tried standard HSS mills with radiused corners to no avail. They bounced off like they were made of rubber. I went with something like this and had no problems:

Product Details

I cut over 1,000" of weldment with a single end mill.
 

Gard

Aluminum
Joined
Mar 18, 2016
I will try out some of those carbide end mills, that looks like a good site. What SFM did you run them at on weldments? Any general guide on how much slower to run if cutting dry?
I have used a couple of variable speed cloudline S6 axial fans from AC Infinity for moving air from the wood stove to other areas of the house, they seem to work real well. I bet they would also work well for this.
I guess the files are more or less expendable, when you try a file that gets dull you have determined hardness?

Anyone have any experience with hammer hitting brinell hardness tester? It appears an optical scope is used to measure the diameter of the impression from a hardened ball. No idea if I am attaching the ebay link correctly.

Hammer Hits The Brinell Hardness Tester Portable +Readout Microscope+Test Block | eBay
 








 
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