Thread: Poor finish with my finishing tool.

G'Day,
I can only agree withe previous comments, from the photos the tool looks like a left hander, designed to cut away from the headstock.
And for what it's worth, I as a pimply youth (many, many moons ago) I was taught to support the work with a centre any time the length of cut exceeded 3 times the diameter.
Regards,
Martin

Lather and Simon,
Just standard mild steel black tube I had laying around. To get that sort of finish you need to hone the tool well with a oil stone. I never used any emery cloth on those as it would put out it's accuracy. You can also see you oil covering them to save them from rust. I oil them up and keep them in a plastic bag or they will rust in my shed.

Simon, if you follow that link to the right handed tool I posted you should get good results from it. It is good to see your trying to use HSS, as it's a cheap way of machining and once you get used to grinding them you will wonder what all the fuss was.

If you print those pages out and take them down the shed, you can then just copy the shapes off them while your grinding.

Dave

Will make a tool out of 1/2 "HSS, and give it a try, have been using the diamond holder, which now seems to have troubles holding it's center height when performing deep cuts, even though the tool is tight.

I have never used a diamond tool holder because the HSS sticks seem to work good enough for me. I can machine off 3mm (6mm on diameter) no problems, but I find mild steel likes the a bit of side rake to leave a nice finish compared to other steels. When I was cutting those cylinder squares the shavings where like hair thin or thinner on the final passes.

Dave

Would that be a head hair or pubic hair.

Originally Posted by toolman49

G'Day,
I can only agree withe previous comments, from the photos the tool looks like a left hander, designed to cut away from the headstock.
And for what it's worth, I as a pimply youth (many, many moons ago) I was taught to support the work with a centre any time the length of cut exceeded 3 times the diameter.
Regards,
Martin

That would be depending on the diameter wouldnt it?

LOL, not sure I have never measured a pubic hair, is there a difference?

Dave

Theres a couple of thou in it.

Hi Simon,
Toolman brings up a good point. We've all assumed you are cutting towards the chuck and not away from it?

I tried vertical shear bits but didnt have much luck on very fine DOC. Strange as they work great on the shaper. Maybe you'll do better
Vertical Shear Bit

38*3=114mm

Stuart

Originally Posted by toolman49

G'Day,
I can only agree withe previous comments, from the photos the tool looks like a left hander, designed to cut away from the headstock.
And for what it's worth, I as a pimply youth (many, many moons ago) I was taught to support the work with a centre any time the length of cut exceeded 3 times the diameter.
Regards,
Martin

Hi Martin,

The workpiece started off as 50mm and it was only extending out by about 150 so I'm not being too naughty. Also I thought that by doing very light cuts you can get away with a little more. There can't be too much flex if you look at how close the diameters are at each end....

Besides, my tailstock is nowhere near aligned accurately enough (height wise) to be used without compromising the intended accuracy.

G'day Dave,

Thanks for the links I will have a look and most likely print off and laminate and take back to the man cave.

Lather,

No offence but I take some comfort in knowing I'm not the only one struggling with this. I guess it's not an apprenticeship for nothing.

Michael,

You mean they are using free machining steel? The bastards! I'm doing my head in on this! Oh well, the process has allowed me to pick up on some things I am doing wrong in terms of tool grinding. For me, I feel if I can achieve a mirror finish with HSS on mild steel then I can achieve anything! It's like Mr. miyagi in the Karate Kid catching flies with chopsticks!

Cheers,

Simon

LOL, it's no as hard as catching flies with chop sticks.

Dave

Originally Posted by Stustoys

I tried vertical shear bits but didnt have much luck on very fine DOC. Strange as they work great on the shaper. Maybe you'll do better
Vertical Shear Bit

hi Stuart
Thanks for throwing that bone for me

Phil

Hi Simonl,
I had a similar problem achieving a good finish on that horrible black bar. It is much easier on the leaded steels.You can still get a good finish on the black bar by doing the following.
1.Supporting the work in a centre irrespective of the amount sticking out from the chuck.
2. You must have a razor sharp tool, the shape of the tool is not that critical as with a finishing depth of cut of .002"-.003" you only have the radius nose doing the cutting.
3. Turn at very low speed 50 rpm and the lowest feed you can.
4 Use coolant.
I have tried a large number of different tool styles,shear tools, diamond tools, double angled tools and all are capable of a good finish if you do the above steps. Not all that Black bar is the same quality.
Bob

Thanks Bob & Phil.

There have been lots of replies on this thread for me. Lot of things for me to try differently to what I am doing now.

Thanks

Simon