One for you hobby lathe machinist!

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bucketboy

bucketboy

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Apr 5, 2019
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Lincolnshire, United Kingdom
I have a medium sized lathe, while it can produce some good results, heavy cuts and particularly parting off or long boring bars causes chatter, and as everyone machinist knows once is starts it’s difficult to get rid of.

After watching numerous YouTube clips I decided to remove the compound slide and replace it with a solid lump of steel under my quick change tool post. This is clamped to the cross slide by 4 tee nuts. All I can say is WOW! What a difference, I can now double the feed rate and quadruple the depth of cut with no issues. Lighter cuts are giving a better surface finish and parting off is a doddle, chatter is now a thing of the past.
It cost me £60 for all the materials and about 5 hours of machining but time and money well spent 👍

Another couple of tips that I picked up to reduce chatter, under the parting off tool put a strip of sheet copper before clamping down or a piece of soldering wire wrapped around a boring bar. I don’t fully understand why this works but it does.

Bb
 
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I’ll get more pics tomorrow but here is a couple

D8DECE1C-C63F-4ED7-AD2D-15C4497B2DB4.jpeg



90E41822-A16D-4AC3-9513-BB29D2DCEE8E.jpeg


The plate is 100mmx150mmx15mm with a 35mm bore, the bar is 80mm Dia 75mm high that include the 20mm spigot for the quick change tool post and a 35mm spigot for the base plate. The two parts are held together with 4 x 8mm bolts and a M14 stud.

Bb
 
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bucketboy said:
I have a medium sized lathe, while it can produce some good results, heavy cuts and particularly parting off or long boring bars causes chatter, and as everyone machinist knows once is starts it’s difficult to get rid of.

After watching numerous YouTube clips I decided to remove the compound slide and replace it with a solid lump of steel under my quick change tool post. This is clamped to the cross slide by 4 tee nuts. All I can say is WOW! What a difference, I can now double the feed rate and quadruple the depth of cut with no issues. Lighter cuts are giving a better surface finish and parting off is a doddle, chatter is now a thing of the past.
It cost me £60 for all the materials and about 5 hours of machining but time and money well spent 👍

Another couple of tips that I picked up to reduce chatter, under the parting off tool put a strip of sheet copper before clamping down or a piece of soldering wire wrapped around a boring bar. I don’t fully understand why this works but it does.

Bb
Click to expand...
Chatter is just harmonics in the tool, especially boring bars extended to far out. Tool needs to be as short as possible, as a rule carbide bars are 6 to 1 and steel bars are 3 to 1 for maximum extension, but we do what we have to do..lol.
Several ways to deal with it, as a rule, faster feed and slower spindle speed and heavier cut. But always slower spindle speed.
You can put rubber bands on the tool or the part or anything to break the harmonic vibrations. If you have variable spindle speed control, you can go up and down with the spindle speed while the tool is feeding to break the vibrations.
On swiss lathes I have in the past just tightened one rear screw on boring bar instead of two, (one in the front and one in the rear), and this causes the vibrations to go away. So there are many tricks for chatter. Rigidity is key.
 
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Definitely an improvement for parting off and heavier turning. I made mine from scrap flat stock and cut it to size in my 4 jaw, that can be sketchy though.
I'm going to make a better compound clamp at some point, because I still use it. Here's my rendition...
IMG_6943.jpeg

IMG_6944.jpeg

IMG_6945.jpeg

The aluminum block on the tool post is for holding a coolant line when needed. ✌🏻
 
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I can't imagine getting rid of my compound. But then again, I just finished a project where I had to cut a lot of tapers (for cone shaped items which can inexplicably no longer be discussed here) and the compound is how I got them done. Also, I think my 13" lathe, while not the epitome of rigid, may be bigger/heavier than what you're working with. I'm jealous of your DRO though. I have one for my lathe, but I'm too lazy and scared to start drilling into the lathe to mount it...
 
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extradrygin2001 said:
All you at home machinists should start making the parts for the TX200 the AGH no longer makes. Everyone with a TX200 wants a Maccari stainless steel shoe.

As the standard one has issues with crumbling, and Maccari refuses to make more, it might be something to consider
Click to expand...
If I had a mill I would make them. I intend on getting one at some point. I've thought about this as well.
 
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techna said:
I can't imagine getting rid of my compound. But then again, I just finished a project where I had to cut a lot of tapers (for cone shaped items which can inexplicably no longer be discussed here) and the compound is how I got them done. Also, I think my 13" lathe, while not the epitome of rigid, may be bigger/heavier than what you're working with. I'm jealous of your DRO though. I have one for my lathe, but I'm too lazy and scared to start drilling into the lathe to mount it...
Click to expand...
Who's DRO are you referring to?
 
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bustachip said:
Definitely an improvement for parting off and heavier turning. I made mine from scrap flat stock and cut it to size in my 4 jaw, that can be sketchy though.
I'm going to make a better compound clamp at some point, because I still use it. Here's my rendition...
The aluminum block on the tool post is for holding a coolant line when needed. ✌🏻
Click to expand...
Have you considered using the Clough42 electronic lead screw to get rid of the change gears? I did and could never go back. He will have more in stock soon.

I used the largest nema 34 hybrid stepper motor with a 1 to 1 drive on 70vdc.

www.ebay.com


STEPPERONLINE Nema 34 12Nm Closed Loop Stepper Motor Hybrid Servo Driver CNC Kit | eBay ​


Holding Torque 12Nm. 1 xClosed Loop Stepper Driver 0-8.2A 24-80VDC for Nema 34 Stepper Motor. 1 x Nema 34 Closed Loop Stepper Motor 12.0Nm(1699.68oz.in) Encoder 1000CPR. Closed Loop Stepper Motor + Driver Kit included.

www.ebay.com
With this power supply https://www.amazon.com/gp/product/B01IORDDYU/
and this encoder https://www.amazon.com/gp/product/B08NV91RPS/
I 3d printed the encoder drive gear and mount. It just sticks to the end of the lathe with a 125 lb pull cup magnet.
I used two 60 tooth timing pulleys for a 15mm wide belt 3mm pitch. X2 just for the large pulleys https://www.amazon.com/gp/product/B014A86FME/ because I couldn't find just the large pulleys at the time.

I just built a new open frame stand for my lathe with the stepper motor mounted directly underneath the transmission. I did this to make it easier to keep my lathe clean. With no coolant tray chips can fall down a chute into a trash can. The stand is on 5 inch total lock castors like everything else in my shop for easy cleaning.
 
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heavy-impact said:
Have you considered using the Clough42 electronic lead screw to get rid of the change gears? I did and could never go back. He will have more in stock soon.

I used the largest nema 34 hybrid stepper motor with a 1 to 1 drive on 70vdc.

www.ebay.com


STEPPERONLINE Nema 34 12Nm Closed Loop Stepper Motor Hybrid Servo Driver CNC Kit | eBay ​


Holding Torque 12Nm. 1 xClosed Loop Stepper Driver 0-8.2A 24-80VDC for Nema 34 Stepper Motor. 1 x Nema 34 Closed Loop Stepper Motor 12.0Nm(1699.68oz.in) Encoder 1000CPR. Closed Loop Stepper Motor + Driver Kit included.

www.ebay.com
With this power supply https://www.amazon.com/gp/product/B01IORDDYU/
and this encoder https://www.amazon.com/gp/product/B08NV91RPS/
I 3d printed the encoder drive gear and mount. It just sticks to the end of the lathe with a 125 lb pull cup magnet.
I used two 60 tooth timing pulleys for a 15mm wide belt 3mm pitch. X2 just for the large pulleys https://www.amazon.com/gp/product/B014A86FME/ because I couldn't find just the large pulleys at the time.

I just built a new open frame stand for my lathe with the stepper motor mounted directly underneath the transmission. I did this to make it easier to keep my lathe clean. With no coolant tray chips can fall down a chute into a trash can. The stand is on 5 inch total lock castors like everything else in my shop for easy cleaning.
Click to expand...
Yes I've thought about it, but I don't do that much threading. Was it hard to get it set up and working properly?
 
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bustachip said:
Yes I've thought about it, but I don't do that much threading. Was it hard to get it set up and working properly?
Click to expand...
It was very easy. I had a problem with dirty power to the control board but ended up powering the board from a li-ion battery pack and have had zero problems since. The battery pack can run it for months before needing a recharge but I'm sure I'm the only person that had this problem. It seems to be bullet proof and couldn't be any more simple to use. You can change feed speeds on the fly. I rate it 10 out of 10 and recommend it to anyone with change gears.
 
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The dro is part of the package and was already installed, it is handy but I tend to use the dials for most of my jobs.

With reference to the Clough42 stepper, I did look seriously into one of these but as far as I understand you need to have a basic background knowledge of electronic…..unfortunately that rules me out, I have only just found out how to record on our vcr that my wife bought in 1980☹️

Bb
 
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