Dovetail milling advice

[sco]

Planning on having a go at milling a dovetail at the weekend for a spherical turning tool - detail looks like this http://metal.duncanamps.com/images/hk1160_head.jpg (This is obviously someone else's attempt at the same part).  I'm going to mill each side of the dovetail separately but is there anything special about dovetail milling I should know or just procede as per normal milling?

Cheers for any advice,

Simon.

[Jasonb]

If you are making it as separate parts like in your picture then you don't need a dovetail cutter, just set the work at teh correct angle and mill across teh end with a standard bit or even flycut, it helps to cut teh angle onto the end of a longer bar and then cut it off once the angled part is done.

Used the method for this gear selector

[BillTodd]

I'm going to mill each side of the dovetail separately but is there anything special about dovetail milling I should know or just procede as per normal milling?

To preserve the edge of your dovetail cutter, mill out as much as possible with an end mill & T slot cutter .

Bill

[Stuart]

use plenty of coolant or cutting oil

run it at speed that is worked out for the large end , don't let it rub and do not be afraid of it give it a fair cut your machine will tell you if it is unhappy


for a 25 60deg cutter in steel i would run at 320 x 20 / 25 = 256  on a sx3


20 is the cutting speed for steel in metric bits  and 25 is the cutter big end in mm

Stuart

[Bill Gruby]

 Can't add anything to that answer, well done "Lordedmond".

 "Billy G"

[sco]

Thanks for all replies - I'm going to have a go with the cutter directly as it's difficult to set up the angles to end mill out the shape.  It will be done in the lathe so will have to be quite gentle cuts as the vertical slide is not a very rigid setup.  I'll see how I get on.

[Stuart]

careful when you break out nip up the slide a bit to stop it snatching


good luck


Stuart

[Bogstandard]

Just to add a little to the explanations given.

The deeper you go into the cut slow down your feed. When you first start, it is only the tips that are in contact, so removing little metal, the deeper, the more metal is being removed.

Dovetail cutters are about the most easily damaged, and usually most expensive, cutter you own, so take care of them. I am still using a 1" one that I bought about 20 years ago, the best ?5 I ever spent.

John

[sco]

Well so far so good - been taking small cuts so it's going to take a while but I'm easing the feed as the cut width increases.  Seems to be cutting nicely with no chatter.   Cutter was a secondhand punt off ebay for ?10.

[sco]

All finished - here it is, quite satisfying to use;

 <a href="https://www.youtube.com/watch?v=UVc0ZbVQVoE" target="_blank">http://www.youtube.com/watch?v=UVc0ZbVQVoE</a>

[Stuart]

well done with the dove tails and the added bonus of a very useful tool as an end product



Stuart

[smfr]

Ooh that's nice. I like the idea of a toolpost-mounted ball turner. The carriage-mounted ones don't have enough clearance under the chuck on my machine, so you can't get close to the chuck jaws.

Simon