Power crossfeed help

[Sshire]

It seems as if, when I near the end of a build, I begin thinking about "what's next." I have 4 sets of plans on the bench, but, I would really like a power crossfeed for my lathe (Grizzly G0602 10x22.)
After I made the power carriage feed (independent of the spindle speed) I realized the improvement in surface finish was significant over hand cranking.

I have many questions and some parameters for you guys to follow.

1. There is no room at the rear of the carriage or underneath.
2. This is NOT the first step in CNCing my lathe.
3. I want to be able to use the power crossfeed OR the handwheel without going through some major changeover procedure.

The two possibilities that have occurred to me are.
A. A cogged belt drive with one pulley on the handwheel collar and the other on the motor shaft. The same type of windshield wiper motor that I used for the carriage feed with an H-bridge controller and variable pot.

B. a stepper motor between the crossfeed screw and the handwheel. This would be similar to the CNC conversion but minus the ball screw stuff, etc. Some type of controller to control speed and direction. I know less than nothing about steppers, controllers, etc. but I'm a quick learner. I realize that this will move the handwheel out, but it's not an issue.

Your thoughts are encouraged (actually, I'm begging for advice here)

 

[MCRIPPPer]

maybe a keyed shaft parallel to the threading screw like on a real big lathe. you would need a small gearbox to transmit the power to the crossfeed. if it already has a feed shaft for the carriage, you might be able to couple it to the cross slide.

 

[Sshire]

ripper
Having never seen a real big lathe in operation, I'm not quite sure what you are describing. I'd rather keep the power feeds independent because it seems like more mechanical stuff to change from carriage feed to cross feed.

 

[Sshire]

Sorry guys. I grabbed these with my phone and meant to post them.

 

[canadianhorsepower]

do you have any pics from behind
it should work and what size lathe is it

 

[Sshire]

As i wrote in the first post, no room in the back and it's a 10x22

 

[MCRIPPPer]

on real lathes there are three shafts that run the length of the bed. one is the lead screw, used only when threading. then you have the forward/ reverse shaft which has a lever that makes the lathe go forward or reverse. it is keyed and only moves a few degrees both ways. the third is the feed shaft, which is driven by the spindle, similar to the lead screw. all it does is transmit power into the feed box which is in the carriage. inside the feed box you have gears and clutches that select the cross slide or carriage hand wheels. the reason most lathes dont use the lead screw for feeding is that it wears it out, and the lead screw is no longer good for threading accurately. where i work there is a big lathe that has only one big 20hp motor that runs everything. the motor always spins and the spindle has a clutch that makes it go, and everything is gear driven off that one motor.

 

[canadianhorsepower]

As i wrote in the first post, no room in the back and it's a 10x22

Well sorry to burst your bubble But I have one on my Taig

 

[Sshire]

Ripper

The three screw setup sounds great. I see the logic there, but a bit too complex for me and my 10x22. I new there was a reason, other than weight, why "real" lathes are desirable and expensive. I really have to pay more attention to the big stuff when I go to my used machinery dealer.

Luc
All I was trying to do in my first post was to include enough information so that people who are trying to help me wouldn't spend time on something that will not work in my situation. Please lighten up.

 

[dman]

the idea for a power feed that you don't need gear box for can work but you need a low spped motor with extrememly high torque and no reduction drive. the only thing i can think of for that would be a stepper motor with a controler. the reason i say that is because if you don't have the phases switch many times per revolution you will probably stall the motor unless the rpms are higher, too high to easily turn the motor from the carriage end of the gear reduction. well perhaps a normal motor would work if you don't use any worm gears but you will definately notice the drag of the motor. then again the problem with a stepper is that the motor reluctance would not be good for hand manipulation so you'd need to disengage it for some things. perhaps the wiper motor you have will give you the right compromise if it doesn't have too much reluctance.

the belt is probably the best idea but if you got a ball screw with multiple helixes it can also work. and using the factory rack gear could work if you modify the factory carriage to hold the motor.

the alternative to a stepper motor would be some kind of clutch system. the xlo (may also say "ex-cell-o" as the brand) model 602 mill has a nice head that isn't a bridgeport carbon copy. the quill has a 6in stroke rather than 5" and a clutch on the power down feed. when the quill reaches the quill stop it just slips, instead of reversing the feed or relying on the downfeed disengage feature you just over power the clutch and push the lever back with your hand, load a new part as it slowly feeds down and use the handle again to over power the clutch to bring the drill close to the new part, it's one handed operation by not needing to use a feed engage lever as you load multiple parts for drilling. this would be my first choice in a vertical bridgeport style mill because of the head. i've worked with too many bridgeports and BP clones with broken power down feeds and had i discovered the xlo 602 before i bought my induma (italian mill with a little different knee and carriage but has a head identical to a BP) i'd have searched the Internet for a 602.

come to think of it i may want to do something like this to my south bend in the future if i don't take things too far and do a linuxcnc conversion with encoders to allow for teach in features for fast intuitive setups.

 

[canadianhorsepower]

Luc
All I was trying to do in my first post was to include enough information so that people who are trying to help me wouldn't spend time on something that will not work in my situation. Please lighten up.

Sshire..... sorry If offended you buy asking for pictures of the back of your lathe. I had a Busy Bee lathe model ct089 13x24 It looks almost like yours
"that's why I request pictures" and manage to put a flex coupling at the end of the of the compound table. The motor was direct drive to the screw and control with a simple PWM . This way I didn't have to engage or dis-engage it


I'm not a big picture taker if I find some pictures I'll post them

cheers

Luc

 

[Sshire]

Luc
I get what you're saying. The back, when the crossslide is Fully extended, damn near touches the rear splashguard. Also, the DRO bracket is bolted toi the rear of the crossslide.
One of the guys on MEM came up with a (what I thought was a) brilliant idea.
Since I have a motor powering the carriage with a speed control, use a second gear that is identical to the one on the threading dial. That gear is on a shaft with a timing gear pulley on the other end. A second timing gear is behind the crossslide handwheel. A sliding clutch engages and disengages the crossslide gear. I'm working on a drawing now and will post it. I've ordered the thread dial gear from Grizzly and should have it next week.

 

[canadianhorsepower]

when the crossslide is Fully extended, damn near touches the rear splashguard

Ok I wasn't using a back splash on mine for that purpose I had steel plate mounted to the wall
as a back splash

 

[RonGinger]

Put a socket wrench in the chuck of a nice battery powered drill that fits that nut on the end of the shaft. Just pick it up, engage the nut and run it in or out. Also has the advantage that it can power the compound as well.

 

[Sshire]

Ron
I expected an absolutely elegant solution when I saw that you had replied.
I actually got that same response when I got my bridgeport and asked about power knee lifts.
Boy am I glad I read that one. I bought Turbo power feeds all around.

 

[jestes]

Luc
I get what you're saying. The back, when the crossslide is Fully extended, damn near touches the rear splashguard. Also, the DRO bracket is bolted toi the rear of the crossslide.
One of the guys on MEM came up with a (what I thought was a) brilliant idea.
Since I have a motor powering the carriage with a speed control, use a second gear that is identical to the one on the threading dial. That gear is on a shaft with a timing gear pulley on the other end. A second timing gear is behind the crossslide handwheel. A sliding clutch engages and disengages the crossslide gear. I'm working on a drawing now and will post it. I've ordered the thread dial gear from Grizzly and should have it next week.

Do you have any drawings? Did you ever build this setup? I've been pondering the same problem ever since I got this lathe a few years ago.

 

[Wizard69]

It seems as if, when I near the end of a build, I begin thinking about "what's next." I have 4 sets of plans on the bench, but, I would really like a power crossfeed for my lathe (Grizzly G0602 10x22.)
After I made the power carriage feed (independent of the spindle speed) I realized the improvement in surface finish was significant over hand cranking.

I have many questions and some parameters for you guys to follow.

1. There is no room at the rear of the carriage or underneath.
2. This is NOT the first step in CNCing my lathe.

Maybe not but the mechanical solution can be exactly the same. So from that standpoint looking for examples from guys that CNC'ed the machine might be helpful. Even if CNC ins't in your near term future I'd make sure the "upgrade: is applicable to a CNC mod in the future. if not CNC an electronic lead screw solution.

3. I want to be able to use the power crossfeed OR the handwheel without going through some major changeover procedure.

This can be a problem because the motor drives can cause cogging. In other world the smooth feel of a lead screw can disappear. I would do one of two things, make the belt easy to disengage or have the driven pulley sit on a hub that permits disengagement.

The two possibilities that have occurred to me are.
A. A cogged belt drive with one pulley on the handwheel collar and the other on the motor shaft. The same type of windshield wiper motor that I used for the carriage feed with an H-bridge controller and variable pot.

This is often acceptable for basic feed.

B. a stepper motor between the crossfeed screw and the handwheel. This would be similar to the CNC conversion but minus the ball screw stuff, etc. Some type of controller to control speed and direction. I know less than nothing about steppers, controllers, etc. but I'm a quick learner. I realize that this will move the handwheel out, but it's not an issue.

Steppers are somewhat more difficult to implement but basic control that does variable speed isn't a big hurdle. More interestingly if you do a more complex controller you can sync to the spindle and do things like tapers which would be hard to do on a basic DC motor drive.

Your thoughts are encouraged (actually, I'm begging for advice here)

I'd go stepper myself and engineer in an easy way to disengage the drive belt to revert to smooth manual operation.

 

[latheMillMasterMariner]

1. There is no room at the rear of the carriage or underneath.

But there is enough room outside of the carriage. This is my next project.
Cheers
LMMasterMariner

 

[latheMillMasterMariner]

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