Which tool to cut small rods of D2 steel

Hi All.

I've been given some small off cuts of D2 steel rods about 22mm diameter and would like to know what would be the best type of tool to turn them down to a lesser diameter, about 19mm-20mm, on my hobby lathe. Thankfully the D2 off cuts have not been hardened or treated and are still in it's normal state. Should I use HSS, indexible tips or carbide brazed tools? I was thinking of buying some 8mm shank tools from RDG but would appreciate feedback from here on what my best option would be.

Thanks,

JS

Hi,

D2 is a very tough steel to machine even in it's normalised state, but there is some data that may be of use here,

Regards

T

Thanks for the reply. I think I've already downloaded that from somewhere else as I recognise the front page, but I don't remember seeing the Machining section on page 6.

All I need to do now is figure out what this means:

Turning Turning
with carbide with high
Cutting data speed steel
parameters Rough turning Fine turning Fine turning

Cutting
speed (vc)
f.p.m. 230–360 360–500 50
m/min. 70–110 110–150 15

Feed (f)
i.p.r. 0.012–0.023 –0.012 –0.012
mm/r 0.3–0.6 –0.3 –0.3

Depth
of cut (ap)
inch 0.08–0.20 –0.08 –0.08
mm 2–6 –2 –2

Carbide
designation
US C2 C2 –
ISO K15* K15* –

* Use a wear resistant Al2O3 coated carbide grade, for
example Sandvik Coromant GC 4015 or Seco TP100.

Can anyone put that into laymans terms?

I guess that is a copy of some data from a table in your last post. I would ignore all of it, as it will only really apply to you if you had a large industrial lathe or machining centre. For a small hobby lathe (you don't specify which one), all of that goes out of the window.

Get hold of a tool that uses good quality carbide inserts, such as the CCMT060204 type used in Glanze tools. Then, just start taking material off, increasing speed and feed slowly up to a point you are happy with the rate of material removal and surface finish. The lathe will soon let you know when it is not happy and you are putting it under too much load!

Anthony

JS, you may find that the swarf will come off in bright blue chips or long lengths with some sparking. Dont worry about but carry on cutting as that is normal.

The swarf will be very hot !

Clive

True, JS did not say which lathe he has. But the vc value of 15 m/min seems very correct for me on any lathe and HSS tooling. I admit that the f and ap values would be a tad high for an Unimat !

Greetings, Hansrudolf

Hmm, my previous reply doesn't seemed to have uploaded. Damn internet dongle.

LAD: Thanks for the advice ref ccmt inserts. Will be looking for a turning tool and parting tool rather than buying a full set. Just need to decide whether I need a right hand or left hand.

Clive: Thanks for the tip ref metals behavour when turning. I'll make sure I've got my goggles on.

Forgot to add, it's just a wee peatol I have, so slow and steady will be the rule of the day. Haven't quite got to the point where I can buy a myford but hope to one day.

Edited By JS on 15/01/2013 01:53:37

JS, you can save for a Myford, or buy 2 or 3 modern imports for the same price. I want a smaller lathe than what I'v got, mine is a 1324 BH type (17" in the gap), 20yrs ago I could have bought 3 of theser the price of a Myford ( the lathe is Taiwanese).

I find that with unknown steel, just a bit of experimenting usually finds a suitable speed and feed, found that fairly early in my time on the lathe when I decided to try turning old car half shafts. Ian S C

I also have an excellent Chinese import (Warco WM280V-F) bought new with a good selection of extras at a Sandown show some years ago. Cannot fault it's performance so far and it is as accurate as I can hope for - in fact better than most Myfords I have used, and the spec is impeccable.

I also have a Boxford BUD - would prefer an AUD but got this for a great price - and for my money it is superior to most Myfords in all but cosmetic finish. There is too much mythology surrounding the Nottingham product, ithey are expensive and no better than many other less expensive alternatives.

Regards

T

Can anyone put that into laymans terms?

---

Start up your machine, give it some welly, and stick your tool in there

I find the blue brazed 8-10mm carbide tools best

With a small machine it probably wont  be stiff enough to turn hard steel, too much flex

Edited By Ady1 on 15/01/2013 11:44:49

^^^ Yep, thats a fair point

Looked up google, about the first comment on the sites I looked at was vertually "your going to have a hard jobgetting a reasonable finish, I think the usual way of finishing D2 is by grinding. The heat treatment is a bit different, the ? cooling is done in a vaccume. They say that although it has a high chrome content, it's not quite a stainless steel. Looks like some hard work, sounds interesting.

Ian S C

I did a bit of experimental turning today using 8mm shanks with tungsten carbide tips and then with indexibles with CCMT06. Naturally for a small peatol such as mine, progress was slow, however, turning the D2 it did. Not very deep cuts, mind you. It did need a fair bit of cutting fluid. Both types of tools successfully removed long curly strips of D2 with each turn. Every so often the chuch would stick but that was mainly due to me trying to cut too deep, too quick. Nice steady slow rotations seemed to work the best. In all I managed to cut a good 2mm off, going from the original 20.4mm down to 18.04mm. Thats if I've read my calipers correctly.

Down side is the cutting blades are already nearing bluntness after half an hour!

Wish I had a bigger lathe.

JS

Forgot to add: I enjoyed my time on the lathe all the same!

Don't worry, you won't be using D2 for all your work (I hope), so your tools will last longer between sharpening. If your using carbide, you should get a diamond lap/sharpening stone or similar, I,v got one called a fisher mans friend, its a steel bar about 6 mm x12 mm x 90 mm, its got a grove on one side for sharpening fish hooks, the important thing was that it cost about $NZ 5, hand for touching up tool tips.

Ian S C

Thanks for link above i always thought Vanadis worked the same as D2 and very little difference to working 01/Silver steel. Wont get a decent finish decent cobalt HSS will work ok but used to use Kennametal Top Notch bull nose great for irregular shapes even turning down good lathe tools.

If you dont like someone give them some annealed M5 about as hard as M2 hardened and tempered.