- Thread starter skotl
- Start date
addjunkie
Member
- Messages
- 13,315
- Location
- Northumberland. Reet oot in the sticks
But youll be fine as long as you wear eye protection! Because it seems you only need it parting off.
Sergei Slovenija
Member
- Messages
- 1,267
- Location
- Slovenija Ljubljana
I also broke my 2mm carbide bit holder, on both sides. And I began to use a larger holder with a 3 mm wide insert, intended for rougher work. Using a height gauge, setting the height of the tip of the cutter showed that I had previously been mistaken with the height and geometric center of the workpiece. I need to make a device for precise positioning (why not today?) and buy at least 4 more quick-change cartridges for cutters in order to adjust the entire set of cutters needed for the job without removing the knives for replacement. Unfortunately, Tripan cassettes, even used ones, are obscenely expensive and are rarely found in our area.
I'm looking at buying parting cutters with a more classic shape, but with replaceable inserts. I think they are stiffer and vibrate less. Also, the work showed that cutting tools for end cutting (cutters curved along a radius), 3 sizes, are needed.
Sergei Slovenija
Member
- Messages
- 1,267
- Location
- Slovenija Ljubljana
I have seen tips from turners that suggest a cutting method in which the cutter is fed alternately along the X-axis. And the groove will be wider than the width of the cutter. This helps to avoid cutter jamming and better chip removal.
Following this video I've tried some highish speed parting using some 3/4" En1a.
850ish rpm which is second to top speed on the lathe. Worked a treat.
I had however managed the same parting using backgear earlier last week. That worked too but the faster turning was much more preferable. I had found the parting tool had some damage near to the tip holder that might have been catching on the work and causing trouble. My issues went away after I filed the tool smooth.
850ish rpm which is second to top speed on the lathe. Worked a treat.
I had however managed the same parting using backgear earlier last week. That worked too but the faster turning was much more preferable. I had found the parting tool had some damage near to the tip holder that might have been catching on the work and causing trouble. My issues went away after I filed the tool smooth.
Other Daniel
Member
- Messages
- 873
- Location
- France, Charente
I've adopted this approach also, with carbide inserts - as fast as you dare (+ maybe a little bit more).
Three things;
The protuberance of the parting blade is set to the minimum neccesary.
Make sure the parting tool is spot on perpendicular to the workpiece.
Once in cutting position, carriage locked.
Then stand to one side and hit the Y feed.
Always terrifying, but seems to work well.
Three things;
The protuberance of the parting blade is set to the minimum neccesary.
Make sure the parting tool is spot on perpendicular to the workpiece.
Once in cutting position, carriage locked.
Then stand to one side and hit the Y feed.
Always terrifying, but seems to work well.
Barking Mat
Cuddler of hedgehogs.
- Messages
- 13,288
- Location
- France, Brittany.
Protuberance, nice word...
Other Daniel
Member
- Messages
- 873
- Location
- France, Charente
Other Daniel
Member
- Messages
- 873
- Location
- France, Charente
True - but what about brass/bronze & plastics ?
Other Daniel
Member
- Messages
- 873
- Location
- France, Charente
It's a personal favourite, and I use it whenever I can
Although, on reflection I may have left myself open to pedantic enquiry (inquiry ?)
See if anyone picks up on it
Guineafowl
Member
- Messages
- 1,167
- Location
- Nairn
I’m saying nothing…Although, on reflection I may have left myself open to pedantic enquiry (inquiry ?)
See if anyone picks up on it
I part off slowly, because you can usually hear things going wrong and hit the stop before ruining another expensive insert holder. Might give this a try, though.
not done it yet
Member
- Messages
- 2,701
- Location
- Lincs/cambs/Rutland/Northants
A rear tool post for parting makes parting off sooo much easier.
He also needs to get things right. That is not 100 feet per minute surface speed! More like 260fpm - but only at the start of the cut - of course, surface speed is reduced towards zero as it cuts to zero diameter. His figure of 100fpm is for HSS, not carbide. Flooded cooling would be better.
He is also demonstrating parting-off too far from the chuck - closer to the chuck, is better.
I always part from the rear (tool inverted) with power feed engaged on my Raglan 5”. Nor do I (normally) use anything other than a resharpenable Cobalt steel blade. Quick Change Tool Posts, with extra overhang, should be avoided with flimsy, worn, light-weight lathes as well, IMO.
He also needs to get things right. That is not 100 feet per minute surface speed! More like 260fpm - but only at the start of the cut - of course, surface speed is reduced towards zero as it cuts to zero diameter. His figure of 100fpm is for HSS, not carbide. Flooded cooling would be better.
He is also demonstrating parting-off too far from the chuck - closer to the chuck, is better.
I always part from the rear (tool inverted) with power feed engaged on my Raglan 5”. Nor do I (normally) use anything other than a resharpenable Cobalt steel blade. Quick Change Tool Posts, with extra overhang, should be avoided with flimsy, worn, light-weight lathes as well, IMO.
Guineafowl
Member
- Messages
- 1,167
- Location
- Nairn
He says it’s 100m/min.
slim_boy_fat
Member
- Messages
- 29,532
- Location
- Scottish Highlands
I surprised myself today, parting off a couple of small parts. Using my rear toolpost, fast speed and plenty of oil for cooling it worked a treat.
Parting off has been something I've never had much confidence in....
Parting off has been something I've never had much confidence in....
