[rrrufusss]

Hello,

After hours and hours of reading through the benchtop forum I've decided to go for it and have purchased a sherline 5400 mill. It hasn't arrived yet but I intend to convert it to CNC after getting accustomed to what it can do via manual control (I'm new to machining so I want to make sure I know how the machine behaves before I automate it).

I've read a lot of posts that describe the Sherline CNC drivers/stepper as underpowered. With that in mind, I'm looking at getting the 270 oz/in 3-axis kit from Automation Technolgies (formerly kelinginc.net) seen here:

High-Torque Stepper Motor, Stepper Motor, Driver, Stepper Motor kit, DC Servo Motor, DC Servo Motor kit, Stepper Motor Power Supply, CNC Router, Spindle, and other Components. Automation Technology Inc

The question I have is this:

Is there a danger in equipping a small machine like the sherline with beefy stepper motors? Can this cause damage to the mill by driving it too hard or something? The other issue I could imagine would be the weight of the motor hanging off the X axis when it's extended all the way to the right.

Like I said, I've read a lot of posts making the opposite argument (that more power is needed) but I want to make sure I'm not buying a set of motors that will tear the mill apart or something.

Any thoughts or experience regarding big steppers on small mills would be great to hear.

This forum is amazing btw, I'm very much a newbie with this stuff but reading through the wealth of existing information has already helped me tremendously.

thanks!
Ben

[Fastest1]

I actually have a couple of Sherlines. My first was an old educational model badged as a light machines. I replaced the electronics with a Hobby CNC Pro kit I built and used steppers in that size range you are referring to. Usually the coupler will slip before any real damage or the stepper will just stall. Neither causes any damage to speak of. Sherlines are very forgiving and a great learning tool. Generally the tool will break, the part might be messed up and have to be replaced and or the machine will be knocked out of tram. My other Sherline is actaully an A2ZCNC Monster Mill. It has some bigger steppers and it they too dont damage anything if run against a stop or similar. When and if you get a larger machine, it wont be as forgiving. Enjoy

[bebob1]

I think it can if you have a super high torque stepper and running at its high torque mode (e.g. low RPM). Say you over dialed your stage to the maximum travel end and you dont have limit switches, the stage can be firmly pressed on another edge, and if your steppers continue to turn you can likely rip the threads off the brass nut and damage the leadscrew as well.

[Fastest1]

Bebob, actually if it the Sherline set up, the method of attachment of the leadscrew uses a very small conical end and a screw down the center to attach the helical coupler. The surface area is so small it won't allow large loads and will slip. I ran my Sherlines without switches for quite a while and have banged the stops hard at rapid speeds too many times to count. I have never had to buy a part for that. Usually just a small disassembly, tighten a few screws, nuts and or bolts, retram and go back to it. Actually I have a G0704 running a 960oz and I can hit the stops with no issues but the stepper stalling. This is one of the advantages of a stepper, IMU a servo would not be so forgiving but IDK.

[bebob1]

Yea I know the sherline uses set screws but on the shaft they machined a flat on it right? So does it still slip then when torque gets too high? The setscrew acts almost like a keyway

[wizard]

It is possible to damage machinery with motors that stall or collisions occur. Will that happen with this modest upgrade, probably not. Realize that as machines wear the risk of stripping a lead screw nut increase. On the other hand if the lead screw nut is worn to the point it is about to strip, the nut would have to be replaced soon anyways.

There are many ways to break things, I wouldn't get too concerned about breaking or bending things with the attached stepper motors. Sure there may be a weird alignment of conditions when something bad happens, but these are fairly well designed machines for their size.

The bigger issue is this, do you really need that much more power in the steppers? will the spindle motor have the nuts to drive the tools properly with that additional feed rate capability? Only you can answer that question. For some it might make more sense to look at a bigger mill, for others an upgrade to the steppers is exactly what they need. Your manual learning process will likely tell your much about the Sherline and how it fits your needs. To be honest I wouldn't even worry about the steppers until after you have had a few months of time on the mill.

[Fastest1]

Though I can understand what Wizard means, I would have gone nuts manually. OTOH the skill set needed to be successful at manual machining would have been very beneficial when entering the CNC arena. I am hypnotized by a robotic program that cuts any material I put down. It took quite a few months if not a year just to get a machine to move. I am still just a beginner but I have a great time. I think I like to work on the machines as much as with them.

[wizard]

Though I can understand what Wizard means, I would have gone nuts manually.

I guess that depends upon where your interests are. Well that and the padding in your wallet. For a long time I simply had no choice as a home CnC machine wasn't possible. For somebody new to metal craft I don't see any hard in a couple of months of learning manual skills. Of course interests do play a role here, CNC allows one to do things that a beginner otherwise couldn't. Mainly this is due to one machine replacing a lot of tooling, machines and other goodies that would be needed in an all manual shop.

OTOH the skill set needed to be successful at manual machining would have been very beneficial when entering the CNC arena.

Each new guy arrives here with different interests and background. If such a person has little real experience handling metal then yeah getting a feel for the milling process is in order. Me I grew up in farm country, while not on a farm per say, we had a garage so I learned much about the simple processes the hard way. Watching a drill bit burn up trying to drill something you shouldn't is a learning experience.

I am hypnotized by a robotic program that cuts any material I put down.

It is neat isn't it.

One reason I'm boning up on CNC tech is that when I do get my mill I figure it will actually be cheaper than fully populating a manual shop. Further even if I had a well equipped manual shop, CNC just makes practicle things that would be extremely tedious to accomplish manually.

It took quite a few months if not a year just to get a machine to move. I am still just a beginner but I have a great time. I think I like to work on the machines as much as with them.

I'm working on the cellar just so I will have a bit of power to hook new machines up to. The idea is to have a project ready for winter. Working on machinery is what I do for a living, it is at times a challenge but often fun. I'd like to put the machine to work making things though.

[waltpermenter]

I guess that depends upon where your interests are. Well that and the padding in your wallet. For a long time I simply had no choice as a home CnC machine wasn't possible. For somebody new to metal craft I don't see any hard in a couple of months of learning manual skills. Of course interests do play a role here, CNC allows one to do things that a beginner otherwise couldn't. Mainly this is due to one machine replacing a lot of tooling, machines and other goodies that would be needed in an all manual shop.

Each new guy arrives here with different interests and background. If such a person has little real experience handling metal then yeah getting a feel for the milling process is in order. Me I grew up in farm country, while not on a farm per say, we had a garage so I learned much about the simple processes the hard way. Watching a drill bit burn up trying to drill something you shouldn't is a learning experience.

It is neat isn't it.

One reason I'm boning up on CNC tech is that when I do get my mill I figure it will actually be cheaper than fully populating a manual shop. Further even if I had a well equipped manual shop, CNC just makes practicle things that would be extremely tedious to accomplish manually.


I'm working on the cellar just so I will have a bit of power to hook new machines up to. The idea is to have a project ready for winter. Working on machinery is what I do for a living, it is at times a challenge but often fun. I'd like to put the machine to work making things though.

So you don't even own a little milling machine or know how to operate it?
walt

[Fastest1]

No they dont have flat, they have a conical taper on the end of the screw and on the internal bore of the coupler. The screw runs directly thru the middle of the screw parallel with its length. If too much torque is or was applied, it would just slip. I have had that problem quite a few times, no damage was ever done to the machine. I have tried to freeze and heat them together for a better fit, locktite etc. but it will still slip. Stalling is usually the issue as these stepperss arent as powerful as people are giving them credit for. We are not talking a 960 oz nema 34 or anything similar.

Yea I know the sherline uses set screws but on the shaft they machined a flat on it right? So does it still slip then when torque gets too high? The setscrew acts almost like a keyway

[Fastest1]

Just to clarify a little more. In my shop right now I have many machines in various forms of disrepair. Wizard, I too lived on a farm for a while in my youth. I have been around tools, manufacturing, farming, welding etc. Not that I am very good at most but exposed for sure.
I had no mentors except the wonderful people here on the Zone/Mach3, YouTube and various Yahoo forums. There is a quite a bit to learn and if you like a challenge, you will get one.
Inventory as of now
HF 12 x 40 manual lathe
HF RF30 manual
Dyna Mechtronics DM3000 CNC lathe with 6 position tool changer
Dyna Mechtronics DM2400 CNC 3 axis mill
Sherline Lathe converted to CNC
A2ZCNC Monster Mill (originally a Sherline but I couldnt keep awway from the A2Z catalog) now being used as the base of a 3D printer.
And enough extra parts to build an additional Sherline mill or lathe (all of the original Sherline stuff).
I have stalled each 1 of the above CNC machines too many tiimes to count with NO damage. You will lose position obviously and the program would have to be restarted and rereferenced. I have also milled things I didnt mean to (the vise, clamps, fixtures, etc). I promise those lessons will hurt much less on a Sherline! Though you might have the E Stop in your hand it isnt ever close enough.

[wizard]

I've been working on and off with two at work for ages now. Just because owning one at home wasn't possible doesn't mean I don't know how to use one. At work it is part of a shop established for repair of automation equipment.

My points remain though, CNC isn't everything and getting to know and understand metals is invaluable. This is often the case when doing repair and modification work because much is done manually, in the field or with equipment of limited means.

By the same token CNC allows somebody to setup a very capable shop without the need to invest in many of the tools needed for manual approaches to machining.

So you don't even own a little milling machine or know how to operate it?
walt

[wizard]

Just to clarify a little more. In my shop right now I have many machines in various forms of disrepair. Wizard, I too lived on a farm for a while in my youth. I have been around tools, manufacturing, farming, welding etc. Not that I am very good at most but exposed for sure.

Just by that description I'm fairly confident that you have had a lot more exposure to metal working than many when starting out. I sometimes take for granted things I've learned in my youth while looking at somebody staring at me with a blank expression on their face.

I had no mentors except the wonderful people here on the Zone/Mach3, YouTube and various Yahoo forums. There is a quite a bit to learn and if you like a challenge, you will get one.

This is very true.

Inventory as of now
HF 12 x 40 manual lathe
HF RF30 manual
Dyna Mechtronics DM3000 CNC lathe with 6 position tool changer
Dyna Mechtronics DM2400 CNC 3 axis mill
Sherline Lathe converted to CNC
A2ZCNC Monster Mill (originally a Sherline but I couldnt keep awway from the A2Z catalog) now being used as the base of a 3D printer.

That is a huge inventory! It has taken me years to get the little bit that I have which currently amounts to a 9x20 generic lathe, drill press and a bunch of wood working tools.

And enough extra parts to build an additional Sherline mill or lathe (all of the original Sherline stuff).
I have stalled each 1 of the above CNC machines too many tiimes to count with NO damage. You will lose position obviously and the program would have to be restarted and rereferenced. I have also milled things I didnt mean to (the vise, clamps, fixtures, etc). I promise those lessons will hurt much less on a Sherline! Though you might have the E Stop in your hand it isnt ever close enough.

Yeah, people don't realize how slow they are until they see a machine do a no no while they are punching at the E-stop with all the speed they can muster. I remember one of my first jobs after leaving high school was in a die casting shop. The engineer in charge was having trouble with one of his dies so he had me sitting there monitoring the machine for a screw up with the idea that i would hit the e-Stop before damage was done. Those machines would snap open and shut so fast there was simply no way.

In any event side tracked a bit there. I think the point is yes you could potentially go nuts trying to do a CNC suitable project manually. That isn't what I'm trying to sell though. I think it is vary valuable to learn to work metal with manual tools to the point of using hacksaws files and the like. In my line of work much is still done with manual tools to get a machine back in running condition of making an improvement here or there.

[Bob La Londe]

I don't think 270 oz in is really significant. I don't own a Sherline however. I do own a Taig, and I have hit the stops a couple times pretty darn hard. Usually it just stops, but I have sheared the little plastic pins in the pin coupler. I am running 380 oz/in motors on the Taig. The potential for damage is there, but the significance of the risk is really up to you to determine.

Now on a big mill you could most certainly do damage. Imagine a thousand pound table and cross slide hitting the mechanical limits at 250 IPM. Bad things will happen.

[neilw20]

You can put a rubber donut on the screw as a bumper, with a bit of lost travel