Hello.
Has anybody ever made a transmission to allow slowing the lathe speed
down to about 20 to 40 RPM or so. I Guess what I'm thinking of is for it
to act like a south bend back gear. (Slow with lots of torqe)
Any idea's would be great.
Thank You.
Ken.
Belt/Pulley Reduction transmission for the HF44142 lathe
Moderator: Harold_V
Belt/Pulley Reduction transmission for the HF44142 lathe
Last edited by ken572 on Wed Sep 08, 2010 7:36 pm, edited 2 times in total.
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
The best learning experiences come
from working with the older Masters.
Ken.
Belt/Pulley Reduction transmission for the HF44142 lathe
Hello Harold,
It's much nicer turning threads when the machine is turning slow.
It is also nice for lite ornamental iron twisting etc.
Ken.
It's much nicer turning threads when the machine is turning slow.
It is also nice for lite ornamental iron twisting etc.
Ken.
Last edited by ken572 on Wed Sep 08, 2010 7:37 pm, edited 2 times in total.
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
The best learning experiences come
from working with the older Masters.
Ken.
Ken,
I would encourage you to chase threads at greater speeds. It's not all that difficult to do, and tends to yield a much better thread when you machine faster.
You should be able to run a typical thread (16 pitch or finer), at a speed of at least 120 rpm, maybe even greater, to a shoulder, and to pull out.
Here's a little exercise you can do to improve your skills at threading. Use aluminum, which is very forgiving of overrunning an existing thread. Put a pencil line around the part you'll practice on, then run the machine at a modest (reasonable) speed, and pull out and open the half nuts as the tool hits the line. It's done in one, fast, smooth move. It's much easier if you set your cross slide handle @ 10:00, so all that is required is a fast downward motion on the handle. Remember to lubricate the cut well, regardless of the material (excepting leaded brass).
Don't use an indicator, because the advancing compound will get you in trouble. Focus on the line. After a few attempts, I think you'll be pleasantly surprised to find you can pull out perfectly well, leaving a decreasing depth of thread, or stopping in a thread relief. Do this exercise until you are comfortable. You will never regret the time you spend, for it will set you free.
I understand the need for twisting----but make sure the machine is robust enough to take the punishment. A light duty machine may not be.
By the way, welcome to the forum!
Harold
I would encourage you to chase threads at greater speeds. It's not all that difficult to do, and tends to yield a much better thread when you machine faster.
You should be able to run a typical thread (16 pitch or finer), at a speed of at least 120 rpm, maybe even greater, to a shoulder, and to pull out.
Here's a little exercise you can do to improve your skills at threading. Use aluminum, which is very forgiving of overrunning an existing thread. Put a pencil line around the part you'll practice on, then run the machine at a modest (reasonable) speed, and pull out and open the half nuts as the tool hits the line. It's done in one, fast, smooth move. It's much easier if you set your cross slide handle @ 10:00, so all that is required is a fast downward motion on the handle. Remember to lubricate the cut well, regardless of the material (excepting leaded brass).
Don't use an indicator, because the advancing compound will get you in trouble. Focus on the line. After a few attempts, I think you'll be pleasantly surprised to find you can pull out perfectly well, leaving a decreasing depth of thread, or stopping in a thread relief. Do this exercise until you are comfortable. You will never regret the time you spend, for it will set you free.
I understand the need for twisting----but make sure the machine is robust enough to take the punishment. A light duty machine may not be.
By the way, welcome to the forum!
Harold
Belt/Pulley Reduction transmission for the HF44142 lathe
Hello Harold 
Thank You for the welcome and also for the advice on threading.
Any and all advice is always welcome here.
Ken.
Thank You for the welcome and also for the advice on threading.
Any and all advice is always welcome here.
Ken.
Last edited by ken572 on Wed Sep 08, 2010 7:37 pm, edited 2 times in total.
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
The best learning experiences come
from working with the older Masters.
Ken.
Re: Gear Reduction transmission for the HF44142 lathe
What diameter threads are you planning? 30rpm is approximately what we used to turn at when threading 2" pipe. Smaller diameters turn faster to maintain the actual speed past the tool.ken572 wrote:Hello.
Has anybody ever made a transmission to allow slowing the lathe speed
down to about 20 to 40 RPM or so. I Guess what I'm thinking of is for it
to act like a south bend back gear. (Slow with lots of torqe)
Any idea's would be great.
Thank You.
Ken.
Would you have enough room to modify/manufcture new step-pulleys with an extra sheave on each? It might be the simplest solution.
Belt/Pulley Reduction transmission for the HF44142 lathe
Hi Torch,
You are correct about the speed of a pipe cutter.. That's about how fast our Rigid unit was. I want to beable to shift in increments of about
10 RPM steps from say 20 RPM up Thru 160 RPM. 160 is the low end
on a HF44142. This will give me the freedom to adjust speed when my
crazy little inventions and projects call for it. Thank You for your input.
Ken.
You are correct about the speed of a pipe cutter..
That's about how fast our Rigid unit was. I want to beable to shift in increments of about10 RPM steps from say 20 RPM up Thru 160 RPM. 160 is the low end
on a HF44142. This will give me the freedom to adjust speed when my
crazy little inventions and projects call for it. Thank You for your input.
Ken.
Last edited by ken572 on Wed Sep 08, 2010 7:37 pm, edited 2 times in total.
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
The best learning experiences come
from working with the older Masters.
Ken.
Re: Gear Reduction transmission for the HF44142 lathe
Hmmm. 14 additional speeds. That's a lot of step pulleys! Or gears for that matter. Even the 4" and 8" Landis machines we had in the fab shop were only 8 or 10 gears.ken572 wrote:Hi Torch,
You are correct about the speed of a pipe cutter..
10 RPM steps from say 20 RPM up Thru 160 RPM. 160 is the low end
on a HF44142. This will give me the freedom to adjust speed when my
crazy little inventions and projects call for it. Thank You for your input.
Ken.
When I was researching my purchase, I paid particular attention to the most popular modifications users made to the various machines. One of those is replacing the motor with a DC unit and variable speed controller (often scavenged from a treadmill, which doubles as a source for the controller).
Besides the variable speed function, DC motors offer the advantage of an inverse torque/speed relationship -- the slower the speed, the greater the torque -- without the temperature problems associated with under-volting an AC motor.
Perhaps it would be easier to explore this option rather than build a huge gearbox?
Belt/Pulley Reduction transmission for the HF44142 lathe
Hi Torch..
The problem I have found when I used V.V.D.'s V.F.D.'s and D.C.
controller's was that even after you spend all the money for new motors
and controller's and then setup and tweaks, you end up with one small
window of speed with max torqe. With belts and or gears I can go 50% bigger on the motor to make up for friction losses and then every step I slow down my usable torqe goes up.
Thanks. Ken.
The problem I have found when I used V.V.D.'s V.F.D.'s and D.C.
controller's was that even after you spend all the money for new motors
and controller's and then setup and tweaks, you end up with one small
window of speed with max torqe. With belts and or gears I can go 50% bigger on the motor to make up for friction losses and then every step I slow down my usable torqe goes up.
Thanks. Ken.
Last edited by ken572 on Wed Sep 08, 2010 7:38 pm, edited 2 times in total.
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
The best learning experiences come
from working with the older Masters.
Ken.
Re: Gear Reduction transmission for the HF44142 lathe
The window is peak power, somewhere near half speed usually, not torque, but I know what you mean. The answer of course, is install a bigger motor while you are swapping it out anywayken572 wrote:Hi Torch..
The problem I have found when I used V.V.D.'s V.F.D.'s and D.C.
controller's was that even after you spend all the money for new motors
and controller's and then setup and tweaks, you end up with one small
window of speed with max torqe. With belts and or gears I can go 50% bigger on the motor to make up for friction losses and then every step I slow down my usable torqe goes up.
Thanks. Ken.
Seriously, Harold may have a good point. Too much torque may twist the bed or do other damage.
Belt/Pulley Reduction transmission for the HF44142 lathe
Hi! Torch,
As I remember on the units I used in the past, the max useable torqe
was at (Full Amp Rating) and at (Rated Speed of the motor) and
on the V.F.D.'s as you lowered the frequency you had to derate the load
or torqe otherwise you would trip the soft limits in the V.F.D. You did not
gain torqe as you slowed to a lower speed. On the D.C. controllers they
have a max rated amps before you trip. As you lower the voltage/speed
when under max load the current goe's up and trips. The V.V.D.'s From
back in the day acted almost the same as the D.C. Controller's. This is a
problem I can get around with gears/belts etc.
Yes, I will have to take care not to twist or tweak the lathe bed.
Thanks Ken.
As I remember on the units I used in the past, the max useable torqe
was at (Full Amp Rating) and at (Rated Speed of the motor) and
on the V.F.D.'s as you lowered the frequency you had to derate the load
or torqe otherwise you would trip the soft limits in the V.F.D. You did not
gain torqe as you slowed to a lower speed. On the D.C. controllers they
have a max rated amps before you trip. As you lower the voltage/speed
when under max load the current goe's up and trips. The V.V.D.'s From
back in the day acted almost the same as the D.C. Controller's. This is a
problem I can get around with gears/belts etc.
Yes, I will have to take care not to twist or tweak the lathe bed.
Thanks Ken.
Last edited by ken572 on Wed Sep 08, 2010 7:38 pm, edited 2 times in total.
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
The best learning experiences come
from working with the older Masters.
Ken.
For what it's worth (probably not much) speed changes are not generally in equal steps. 20 to 30 RPM is a very significant change but 150 to 160 RPM is not. It is better to change in constant ratios such as 1.5x. This would give you speeds like 20, 30, 45, 68, 102, and 153, providing a useful change between each speed and not crowding the higher ones together.
Posssibly the best/easiest thing to do would be to arrange a two stage countershaft system of v-belts with two ratios in one stage and three ratios in the second stage. This would give you six ratios. Or you could use a 2x4 sytem for 8 ratios or a 3x3 system for 9 ratios.
Don Young
Posssibly the best/easiest thing to do would be to arrange a two stage countershaft system of v-belts with two ratios in one stage and three ratios in the second stage. This would give you six ratios. Or you could use a 2x4 sytem for 8 ratios or a 3x3 system for 9 ratios.
Don Young