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View Full Version : Dovetail Cutters

Tony
01-08-2014, 10:44 AM
Was I sick the day they taught us how dovetail cutters are spec'd?

I'm looking for a 55* for my little rebuild project -- but that aside, I see them spec'd
by major diameter x angle.. no actual 'face width' like you'd see, say, a T slot cutter spec'd.

For example:
1" x 60*, 25mm x 55*, 35mm x 45*, etc, etc.

I've only found one ebay seller (Hong Kong!) that actually specifies a "face width" or
what might be better described as "cut depth".

My tails are 1/2" tall -- I'd really hate to try to match two 1/4" cuts along the dovetail face.

RussZHC
01-08-2014, 11:52 AM
Tony:
I found that too...compared to "T" slots however one potential issue is often solved, that being with a T slot you can have very limited amounts of "extra" space i.e. a T slot cutter will have multiple dimensions since it leaves a pretty precise space of that T shape. I think I am correct in saying with many dovetails, there is often quite a bit more space to work with i.e. I can not recall on a metal working machine a dovetail that was exactly or near exactly the shape the dovetail cutter was...you have the angle but the opposite "side" of the dovetail is often quite a lateral space away.

More directly to you question, the only "answer" I could come up with is mathematics...provided you have room for the diameter of the cutter on the "opposite" side of a given dovetail you can cut dovetails of different face lengths (to the max of that face only of course). Don't know that it matters if only say the 1/4" closest to the tip of a 3/4" long face is used. So, if I am reading your concern correctly, buy a cutter that will be more than long enough on its face (not sure what happens if that means the diameter is very large, re: can the machine turning it handle it...)
Now I could be very, very wrong and missing something completely [still waiting to use said cutter, bought with other items at a very good price]

Edit: just thought of something else sort of related, if you are buying horizontal milling cutters with angles, you run into the same issue...first you need to figure out if the supplier is talking included angle or just one side and then you have to take into account how thick said cutter is...a 45* cutter 1/2" thick gives very different length of face than a 45* cutter 1" thick (and the latter might need a very much heavier and more powerful machine...)

jlevie
01-08-2014, 12:08 PM
Give the major diameter and angle you can work out what the flute length can be from the shank diameter. A smaller shank yields a longer flute.

Frank Ford
01-08-2014, 12:21 PM
McMaster and Enco give the height of the cutter edges in their regular listings:

http://www.mcmaster.com/#dovetail-milling-cutters/=q5w353

http://www.use-enco.com/CGI/INPDFF?PMPAGE=114&PMITEM=367-0051

Tony
01-08-2014, 02:17 PM
I bought two from ebay. I think I can mount them both in the same collet and get twice the cut depth.

that was a joke.

they're from hong kong. my first explicit/direct 'overseas' purchase. \$50 each but free
shipping. I'm in no rush, we'll see when they get here and what actually shows up.

are 55 hongkong degrees the same as 55 US degrees?

with my luck they'll be 55 degrees the other way.

Thanks all. Looks like Frank is correct, they do appear to list the info -- I just happened to be looking at
hard to find 55* cutters.

jlevie: that was my first reaction, too -- but if you have a look around the shank is ground above the cutter
end into what appear to be random geometries. Not to mention you can get large diameter cutters with relatively
small face width. Truncated, it would appear.

Russ, yes I have plenty of space in the dovetails -- essentially wide open. I just didn't want to have to
deal with stepping over on an angled dovetail face.

jlevie
01-08-2014, 02:59 PM
jlevie: that was my first reaction, too -- but if you have a look around the shank is ground above the cutter
end into what appear to be random geometries. Not to mention you can get large diameter cutters with relatively
small face width. Truncated, it would appear.
Right! That is why I said "you can work out what the flute length can be from the shank diameter". That gives you the maximum and then you have to see what the cutter looks like to see how much of that you have.

KJ1I
01-08-2014, 06:11 PM
Just for others, since you've ordered the ones you need, VME also lists cutter height, but then again, they are 45* and 60*.

http://www.victornet.com/report/Dovetail-End-Mills/461.html

GEP
01-08-2014, 06:27 PM
It would be interesting to know the difference in quality