My first use of a lathe to make something useful :)

[Brendon M]

Hello Paul, considering that 6 pieces of tool steel cost me $20AUD, you got a bargain

[Brendon M]

Hello again,

I finally purchased myself a bench grinder, a Linishall BG8 model.


I also had my first "D'oh" moment on the lathe.

I was working on Metal Scriber Mk II using a piece of previously turned down 3/8th inch brass rod. All was going well; I just finished cutting the taper, but instead of backing out the cutter, I accidently turned the wrong way and plunged it in, carving out a wide ring in the scriber. 

I attempted to correct it by re-cutting the taper until the ring disappeared; unfortunately the length of the scriber was now too short, and the taper too long. 


Oh well, on the plus side it only took me 25 minutes this time to turn down the next bit of 1/2 inch brass rod stock down to 3/8th, so at least I am getting faster at starting from scratch 

[Admiral_dk]

Turning a dial the wrong way - We have all been there 

[crueby]

Yup, as they say, Practisse Makes Prefect!   

Been there. Done that. Will do it again, I'm sure...

[Brendon M]

Thank you both

Yes I can definitely appreciate the advice given to me when I made my intro post on this forum: "start small".

I am starting as small as possible and I'm still making errors 

[AOG]

For what it's worth, in my experience you will always make mistakes. In the beginning, you start with the make thrice use one method of machining (I know because I exited that phase not so long ago.) eventually you build a bag of tricks to fix your screw ups or work around them by adjusting the dimensions of the other parts. Keep at it and you will learn from your mistakes and start to build your own bag of tricks. One of the things this forum is great for, is that when you screw up and you don't know how to fix it ,people here will let you borrow some of their bag of tricks to help you through the rough spot.

Tony

[DTR]

"One who makes no mistakes makes nothing at all"

[10KPete]

Thank you both

Yes I can definitely appreciate the advice given to me when I made my intro post on this forum: "start small".

I am starting as small as possible and I'm still making errors 

And that's the important thing; they are small errors!!

Pete

[Wabeco D6000E]

Joining the Hackerspace or Makerspace is a great idea.  I did that locally because of the CNC equipment.  I learned how to draw models on Autodesk inventor and can bring the file in and run it on a CNC mill.  People are there to help to things.  And can see what other people are doing.  $20 per month and I can use a Haas CNC mill or lathe and all the other machinery there. 

[Brendon M]

Hello again

I finally managed to create a metal scriber, as described here.



I can finally tick this off, only needed three attempts At least from the failed attempts I had scrap brass stock to try machining operations on first to see what could possibly go wrong.

For my next project, I am going to attempt something more complex: a benchtop gyroscope

What I have not figured out yet is how I'm going to drill out the 6 holes in the flywheel accurately.

[Admiral_dk]

Congratulations - it looks great and you should be very happy with it 

Chris at the site you linked to showed it nicely - if you have a mill - if not .... I cheat. When I did my Viking 2.5cc diesel, I used the lathe to mark the centre diameter of the holes. Next I used a digital angle meter on the chuck, set it to zero, turn the knob for the cutting depth to make a small line across the diameter mark. Backed the tool a bit and rotated the chuck until the angle meter shoved 60 degrees, turned the knobs again to make the next small mark. If you repeat this another five times, you end up with a circle divided by 6. Another way of doing this with the divider, as the radius of a circle divides it into 6 or 60 degrees apart.

[steam guy willy]

Hello again,

I finally purchased myself a bench grinder, a Linishall BG8 model.


I also had my first "D'oh" moment on the lathe.

I was working on Metal Scriber Mk II using a piece of previously turned down 3/8th inch brass rod. All was going well; I just finished cutting the taper, but instead of backing out the cutter, I accidently turned the wrong way and plunged it in, carving out a wide ring in the scriber. 
I was demonstrating an old Drumond lathe to a friend recently and the top slide had a right handed thread installed!!. So every time i tried to take a cut it moved in the wrong direction !!! i think it was maybe a left handed persons lathe or something else..........
I attempted to correct it by re-cutting the taper until the ring disappeared; unfortunately the length of the scriber was now too short, and the taper too long. 


Oh well, on the plus side it only took me 25 minutes this time to turn down the next bit of 1/2 inch brass rod stock down to 3/8th, so at least I am getting faster at starting from scratch 

[Brendon M]

Congratulations - it looks great and you should be very happy with it 

Chris at the site you linked to showed it nicely - if you have a mill - if not .... I cheat. When I did my Viking 2.5cc diesel, I used the lathe to mark the centre diameter of the holes. Next I used a digital angle meter on the chuck, set it to zero, turn the knob for the cutting depth to make a small line across the diameter mark. Backed the tool a bit and rotated the chuck until the angle meter shoved 60 degrees, turned the knobs again to make the next small mark. If you repeat this another five times, you end up with a circle divided by 6. Another way of doing this with the divider, as the radius of a circle divides it into 6 or 60 degrees apart.

Thanks Admiral

The hackerspace has a CNC mill, which can be controlled in a manual fashion -- the main question is whether it is sturdy enough for drilling the required sized holes.

I am sure I could just mark the locations out and use a bench drill, but I do not know how accurate do the locations of the hole need to be to avoid the flywheel becoming unbalanced.

[Admiral_dk]

If it is a CNC mill it should be able to do the job, but if it is a CNC engraver router like the small Chinese one we have at work, you will be in trouble (it haven't got the power to do holes bigger than 1.65mm. ~ 1/16" in aluminium) - it might then be useful for marking the holes, using a very small drill bit as starters.

We use our router to insulate route printed circuit boards for prototyping and I use it for starter holes in the boxes - that way I get very precise starts to the drill bit in the big drill press.

Best wished

Per

[Brendon M]

Hello Admiral Per, I got a clarification about the CNC mill -- apparently it is rigid enough to mill steel; however they'd prefer if most people just stick to softer metals like brass, until they get the cutting fluid system working.

Back to my projects... I am getting considerably quicker. I managed to cut a new scriber from brass metal stock in 2 hours completely from scratch. This includes turning the diameter down from 1/2inch to 3/8ths. I did this to record footage as I was presenting my early machining experiments as part of a "bring your hobbies to work" day. The scriber itself isn't very exciting, but it was a great "attention grabber" to have videos of the machining process playing in the background.

OK, so I can definitely say I am done with making scribers!

I decided it was time to move on to something more complicated -- build a cartridge pen. So with every new project, the thread title becomes increasingly inaccurate... This new pen project involved a few new skills:

• Accurately turning down to a required diameter, instead of simply "close enough"!
  
• Cutting an external thread using a die
• Drilling a 2 inch deep hole without breaking off the drill bit inside! :facepalm:

Also, unlike with the previous projects, I simply could not wing it. I had to sit down with pen and paper and work through some dimensions, and plan the order of machining operations, mindful that I needed to carry out all machining that needed to be done on the workpiece in one go, since the three jaw chuck would introduce slight misalignment.

After a few trial experiments, I got this far:



One of the issues I came up against is that the tailstock can only drill 2 inches deep. The cartridge length overall is a bit over 4 inches, and I would prefer if the cartridge hole was 3 inches deep, so that I don't have to drill so deep with the 2mm drill for the pen outlet hole in the pen cap. Unfortunately, I had to finish up before I could get to the target 3 inch depth. This means I am going to have to rechuck the workpiece and do so accurately, so I will need to learn how to use a 4-jaw chuck.

Either way, "fun" awaits!