# A little turn mill project I started getting some progress on.



## Uguessedit (Jul 17, 2019)

Purchased this Bolton 1337g just over a year ago. As you can see in photos it’s used everyday. I’ve worn out the factory lead nuts and screws and half nut, and so on. Pretty much can tell you anything to expect with it and not to buy one for daily use unless you plan to beef it up and convert it with less problematic screws, nuts, linear ways on the Y, etc.. anyways so far I’ve epoxy filled the bed. Bed is level to 2 tenths end to end. Impressive for Chinese but I also spent a week getting it there. Just finished installing hydraulic disc brake and caliper, dual Vfd’s and second spindle however the second spindle is temporarily set on my tool post. I can’t afford the lathe to be down more than a day or two so I have to do what I can, work, go back to upgrades, work some more, then Upgrade again. It has been an enjoyable project. I have a 3kw spindle and vfd for sub and a 2.2kw automation direct and Techtop for main motor. Lathe will soon to 6500rpm and sounds like a loud vacuum cleaner. Brake works excellent however I still need to install the air solenoid and 12v switch. For testing I just reached down and pushed on the fulcrum point. The brake is off eBay for a gokart 150cc ($58 set plus $20 rotor). I made the spindle adapter that will house my timing gear for sub servo direct drive and also has a spider integrated into the back. I also made the 10 rib pulley set we make them in the shop. It all fits under the factory cover nicely. I have some walk around videos on YouTube. Not sure what I will use for motion control but I have centroid, Mach, and Mesa Linux boards all here in a box so I have a few choices on hand besides some ardiuno and other off brand stuff so no lack of options here. I’m just not sure yet which will serve me best for what I’m doing. Almost considering a 3D printer board since they can run near unlimited controls nowadays and perform code. The plan is to replace the saddle top with hiwins I have in the drawer and a large block of duracast to support my turret, z axis spindle over the back, and give me 4 axis of motion within the saddle assemble between spindle and turret. With sub c servo direct drive I suspect I need at least 5 axis controller. I have thoughts about other functions so with two spindles Linux keeps looking like the one but without any personal experience I’m concerned about the steep learning curve only ever uses windows. Here are some photos of where I’m at. I expect this will take me the remainder of this year despite parts on the shelf.


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## Mitch Alsup (Jul 17, 2019)

Ever hear of paragraphs?


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## markba633csi (Jul 17, 2019)

Did you say your lathe goes to 6500 rpm? I'd be concerned about the chuck flying apart


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## Latinrascalrg1 (Jul 17, 2019)

markba633csi said:


> Did you say your lathe goes to 6500 rpm? I'd be concerned about the chuck flying apart


Stupid question here I guess but Is that something one would actually worry about at that speed?
I know that everything has its limits but i would have thought it was bearings or bushings to be the main choke point on speed and would think the Chuck to be one of the most stable pieces!


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## markba633csi (Jul 17, 2019)

Well, most chucks have an upper limit on safe speed,  often printed on them.  They can in fact fly apart with devastating consequences, so I'm told
Ball bearings can too, just from overspeeding them with compressed air- who would'a thought?
Anyhow, be safe


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## Jubil (Jul 18, 2019)

Latinrascalrg1 said:


> Stupid question here I guess but Is that something one would actually worry about at that speed?
> I know that everything has its limits but i would have thought it was bearings or bushings to be the main choke point on speed and would think the Chuck to be one of the most stable pieces!



Did you ever hear of a clutch explosion in a race car? (Sounds like a racing lathe to me unless it's cnc. ;-)) Centrfugal force is a powerful thing and must be respected. 
Same can happen if you turn a grinder wheel above it's rating. The bond of the wheel is not strong enough to resist the centrifugal force being applied. 
Bearings and bushings etc are a relavent area of concern but probably not as dangerous.

Chuck


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## Latinrascalrg1 (Jul 18, 2019)

Jubil said:


> Did you ever hear of a clutch explosion in a race car? (Sounds like a racing lathe to me unless it's cnc. ;-)) Centrfugal force is a powerful thing and must be respected.
> Same can happen if you turn a grinder wheel above it's rating. The bond of the wheel is not strong enough to resist the centrifugal force being applied.
> Bearings and bushings etc are a relavent area of concern but probably not as dangerous.
> 
> Chuck


Yes but we are not talking about an auto clutch, we are talking about a steel lathe chuck spinning at 6500rpm! How many time have you heard about or seen one of them explode?  And to speak to your example of a  clutch hub how many times have you ever seen a car Wheel (not the tire) Explode into pieces?  As i said above, I AM AWARE that EVERYTHING will have a limit but at 6500 rpm i cant even see a cast iron chuck exploding at that rpm....We are Not speaking about 30,000rpm!


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## Bob Korves (Jul 18, 2019)

Latinrascalrg1 said:


> Yes but we are not talking about an auto clutch, we are talking about a steel lathe chuck spinning at 6500rpm! How many time have you heard about or seen one of them explode?  And to speak to your example of a  clutch hub how many times have you ever seen a car Wheel (not the tire) Explode into pieces?  As i said above, I AM AWARE that EVERYTHING will have a limit but at 6500 rpm i cant even see a cast iron chuck exploding at that rpm....We are Not speaking about 30,000rpm!


There are many variables that can impact the maximum RPM of a chuck.  First is diameter, second is material, third is balance, fourth is quality of the material.  If you go beyond the tensile strength of the metal, it WILL come apart.  If it becomes out of balance, parts of the lathe or other machine can get destroyed along with the chuck, flying in directions beyond radially.  Cast iron has a MUCH lower tensile strength than steel does.  A 2" steel chuck may be perfectly happy at 6500 RPM, but I would not want to be in the same neighborhood as a 6" or larger cast iron chuck turning 6500 rpm.  I know how to do the math to determine the radial loading, but do not know the diameter or tensile strength of YOUR chuck.  Please be extremely careful.  When you modify machinery, you become the test pilot.  Ask yourself, and answer honestly, if you have the skills, knowledge, and mindset to be safe pursuing the project at hand.


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## matthewsx (Jul 18, 2019)

Looks like you've been busy....

Don't fear Linux, much more stable than Windows and the user community is very knowledgeable.

Cheers,

John


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## Bob Korves (Jul 18, 2019)

The compressive strength of cast iron is 6.3 – 7.1 tonnes / sq. cm. It’s ultimate tensile strength is 1.26 – 1.57 tonnes / sq. cm. The compressive strength of mild steel is 4.75 – 25.2 tonnes / sq. cm. It’s ultimate tensile strength is 5.51 – 11.02 tonnes / sq. cm. 








						Difference in Properties of Cast Iron and Mild Steel - JASH Metrology
					

When choosing products made from metal, it is important to understand the properties of the metal that the product is made of. Without understanding the property of the metal required for your product or other applications, you would not be able to get the most suitable one for your specific...




					www.jashmetrology.com


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## markba633csi (Jul 18, 2019)

I don't fear the Linux, just the reaper


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## Jubil (Jul 18, 2019)

Bob Korves said:


> There are many variables that can impact the maximum RPM of a chuck.  First is diameter, second is material, third is balance, fourth is quality of the material.  If you go beyond the tensile strength of the metal, it WILL come apart.  If it becomes out of balance, parts of the lathe or other machine can get destroyed along with the chuck, flying in directions beyond radially.  Cast iron has a MUCH lower tensile strength than steel does.  A 2" steel chuck may be perfectly happy at 6500 RPM, but I would not want to be in the same neighborhood as a 6" or larger cast iron chuck turning 6500 rpm.  I know how to do the math to determine the radial loading, but do not know the diameter or tensile strength of YOUR chuck.  Please be extremely careful.  When you modify machinery, you become the test pilot.  Ask yourself, and answer honestly, if you have the skills, knowledge, and mindset to be safe pursuing the project at hand.



A very good explanation. The mind has a hard time processing force, centrifugal force especially. 

Chuck


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