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Endmill terminology
- Thread starter garageguy
- Start date
Ironman
Ultra Member
Lead – The axial advance of a helical cutting edge in one revolution.
Here is the rest of the story https://mastercuttool.com/endmill-design-basics/
Here is the rest of the story https://mastercuttool.com/endmill-design-basics/
No, think about it more like a screw. In fact, how about a "leade screw". It is how fast the flutes of the end mill are twisted on the end mills axis.
In a rifle bore it would be called twist rate.
@Susquatch I think you are talking about helix angle, apparently lead has to do with the end cutting profile of the cutter. Very interesting stuff but seems highly specialized for only specific operations. Check the page I referenced above.
Nope. I'm not. However, I do believe the helix angle is what ends up resulting in the leade. The references I found (cuz I have no expertise in the matter at all) described it more or less the same way that @Ironman described it above.
I'm inclined to accept his version over others because it makes sense (not that I would ever let lack of sense get in my way....) in the same vein as a leade screw does.
However, if you can provide an etymological development to the contrary, I might be convinced otherwise.
Although many on here prolly think I'm crazy (and I am), I don't find technical references (even by experts) to be universally accurate. I believe it's always good to question the experts. After all, once upon a time the experts all thought that ______..... (fill in the blank yourself).
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Former Member
Guest
FYI Harvey Tools is more than willing to send you a Catalog which is very informative and educational. BUT, if you ask for the free catalog it comes with a 27.00 price into Canada.
Don't ask.
Don't ask.
No. Been there, done that. Have purchased the odd out of date McMaster-Carr Catalog, just so I knew what to call the thingymawhatsit that I was looking for!
Sucks sometimes, living out in the Boonies. Other times, it's worth the costs involved!
Chicken lights
Forum Pony Express Driver
Can you use any end mill to cut with the flutes? Or are some that you can only use the end cutters to cut with?
And how do you determine barrel twist rate?
You need a cleaning rod with bearings in the handle.
Using a tight fitting brush, or patch, push the cleaning rod 3/4's the way down the bore. Pull back about an inch or so. Put a pen mark on the cleaning rod TDC, at a point on the barrel/action, retract the cleaning rod slowly, it will start to follow the rifling, when that mark is TDC again, put another mark. Measure the distance between your two marks. That is your twist rate. Do it several times to get consistant results. (There'll be some slippage but it should be pretty accurate.
I think that any endmill that has sharp side flutes can be used to cut sideways. But some smart butt on here will prolly come up with an exception.
Basically, the vast majority of end mills will cut sideways. Most of the exceptions are the other way around - they will cut sideways but don't always plunge mill very well. You can usually tell by looking at the side edges to see if they are sharp for side cutting, and the center of the end to see if it has cutting edges at the center. Also, some endmills will cut a section of a cylinder but can't plunge a full cylinder.
I do it like @the Stelster recommends but only mark the start and stop when I am sure the patch is following (turning with) the rifling. Done that way, it works in both forward and reverse direction. The key is as he says, the handle must have ball bearings and the patch must be tight enough so it doesn't turn. I've watched guys use loose patches and ordinary rods and I've also seen them get numbers all over the map. It helps to make sure you do it enough times to be sure you are getting consistent results.
Last, but not least, don't count on manufacturer's specifications!
Former Member
Guest
Down load the App, free and does all that along with drawings and details.
Didn't know it existed. Downloaded and installed just now. I'll check it out later.
Except that I cannot have it sitting in the reading room, available for me to open at random, and see something that I did not, up till then, know I needed!
Same reason I like wandering the aisles in various specialty Supply Houses in several fields, Simply knowing that something exists, is of more value to me, than is knowing where to get something I already know I need!
One real good example, is a place called Bedrock Supply in Edmonton. If you can wander through there, and not have ideas going off like fireworks in your head, you need to be watered more often, as you have the capacity of a house plant! LOL!
Dunno how much stuff I bought at Princess auto, from when they used to have actual surplus stuff, just in case...
Besides that, I can shop online for almost anything, once I know what it is. But it drives me near stupid, trying to tolerate loading page after page after page, of an online catalog, just to get past the variety of say, bolts, that they have, when I already know they have bolts of all sizes...
I do this too. It drives my bride bonkers. I like to go up and down every aisle just to see what's there. The ideas propagate like fireworks in a barrel. I also remember what I saw so any future need that arises gets solutions from my memory banks.
Get used to saying that, happens all the time to me as I learn more about working with metal.
Chicken lights
Forum Pony Express Driver
I have a couple cleaning rods (that look identical but different brands) that the handle spins freely but I’m guessing they aren’t ball bearing quality. I’ll see what I can beg or borrow because now I’m curious to try this. Thanks!
The leade/lead is marked so the guy that runs the CNC Tool and Cutter Grinder can simply punch in the number, and have the edge re-ground/sharpened, without having to spend any time on probing cycles or any other methods of determining the helix of the mill.
The old school method requires a pretty skilled touch, as the edge being ground has to rest on a height adjusted 'finger' wile the end mill is slid along past the grindstone.
Has naught to do with the 'end' or it's treatments (which can be a whole 'nuther can of worms!). Like Alice's Restaurant, you can get about anything you want, done to the end, especially now that CNC grinding is so prevalent. I happen to REALLY like a .020" or so radius, rather than a sharp corner, on carbide mills. The radius makes them almost eternal lasting when used for Aluminum. Really handy when the drawings call out a specific Rad and you can order the mill out of the catalog, rather than waiting for custom grinds.
Old school helical milling is a lot of fun. When it all works out according to plan. Made some neat 'for pretty' stuff doing it on a manual mill.
Stellrammer
Well-Known Member
An interesting thing I’ve shared with programmers is a formulation for endmill advancement for a constant 2 flute engagement with the work piece, to prevent vibration.
This is done by a combination of depth of cut and feed rate, 2 flute contact minimizes vibration, ie how much feed is needed at .020” DOC at 1/2” length of contact based on the lead or helix of the endmill.
If you take a multi flute endmill,lay it on a sheet of paper, press down on it and roll it it will cut the paper, and produce a series of straight lines evenly dispersed. Then it makes sense how and why it can predict or prevent vibration in certain materials and at various lengths and doc.
This is done by a combination of depth of cut and feed rate, 2 flute contact minimizes vibration, ie how much feed is needed at .020” DOC at 1/2” length of contact based on the lead or helix of the endmill.
If you take a multi flute endmill,lay it on a sheet of paper, press down on it and roll it it will cut the paper, and produce a series of straight lines evenly dispersed. Then it makes sense how and why it can predict or prevent vibration in certain materials and at various lengths and doc.