Hi fellas!! well it´s been a long time since the last time I posted something so… the matter is that I been working with a homemade lathe up to now; I recently bought a metal lathe, self-centering three jaw chuck, but it´s a little slow compared to what I´m used to work with the other lathe (2800 rpm) and I need to know if I can take this lathe to a higher rpm I think it´s actual speed is about 700 rpm.
So.. I´ll be thankfull to hear some experienced turners, better if pipemakers.
regards
Hi Marcelo,
It depends on the lathe (and more importantly, on the bearings). You can do nice work at 700 RPM however - consider that the old makers used treadle lathes. There’s no way they were operating at 1000 RPM. Speed is nice but not necessary and sometimes it gets in the way.
best regards,
Bill
Basically what Bill says and would add that speed is less important than than having correctly sharpened tools
I will describe my own setup in case it is of help
I have two lathes, both are metalworking Boxford’s picked up second hand and these are an AUD (top speed 1400rpm) and the other my main workhorse an Industrial 1130 (top speed of 2240rpm)
Both have Timkin tapered roller bearings
The AUD has been adapted and is virtually an ornamental turning lathe and is used more as a worksetting device with a drilling /milling spindle in the toolpost or vertical slide
The main lathe (the 1130) has a full gearbox and runs in an oil bath and whilst capable of being used at its top speed I am mostly working with it running at between 300rpm and 1100rpm depending upon what I doing and what I am working with. Gundrilling tends to be done at 890rpm and off-centre drilling e.g. barrel units it will down to 300rpm. For reaming and metalworking it will be a lot slower
When using higher speeds a lathe is best warmed up by running for a short while at a slower speed.
I use both captive and hand turning tools as both lathes have adapters for swapping over to woodturning rests
Chris
Thank you both Chris and Bill, you´re very kind and there were the answers I was looking for.
Kind regards
I’ll bet you have some nice low-end torque with that lathe?
If you think your bearings will not support higher speeds, you may be able to replace them with more robust ones.
Have you explored all the relationships of your gears or pullies? If pullies, you may be able to get higher RPM with a larger HP motor and/or a different pully arrangement.
A VFD device can be used to provide direct speed control for the AC motor. Watch out for losing torque at lower speeds though.
There is a lot of information available on the net about improving lathe performance - the cnczone.com forums for instance.
Let us know what changes you make!
I haven´t checked the pulleys ratio but I think I´ll change the one that transmits to the cone of pulleys, it´s too big, but first I´ll check the ratio. Anyway some speed variation can be done with the cone pulleys, still the fastest is slow.
I use a wood lathe for high speed stock removal to get things in the general round shape I am looking for,
Then move to the metal lathe using a medium speed to turn most hard woods.
Using a combination of wood chisels and metal lathe tooling, I can get a very nice finish with lots of control.
I find that most of the harder woods turn like metal and cause a lot more wear and tear on tooling at higher speeds with not that much improvement in surface finish.
At lower speeds you are also not picking as many wood chips out of your pockets.
Tim
“I find that most of the harder woods turn like metal and cause a lot more wear and tear on tooling at higher speeds with not that much improvement in surface finish”
Tim,
If you are using standard type metal lathe tooling to turn tropical woods, then you need to use a similar rake angle on the tool as you would for metal (brass). Read James Lukin’s “Turning Lathes” on Google Books, especially the Chapter on sharpening. Additionally, the tools need to be razor sharp to counter the lower turning speed. What you are after is a ribbon of wood coming off the tool, not sawdust.
Another good refererence is “Tabletop Machining” by Joe Martin.
http://www.amazon.com/Tabletop-Machining-Joe-Martin/dp/0966543300
Good specific sharpening instructions for HSS tooling.
Thanks for the posts Mike and Harlow, very usefull