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9 hours ago, likesToLick said:

Hi @Sophie .  You might find this video from Blondihacks interesting.   She has some useful thoughts about the design,  including making a reversible tip that has both convex and concave centres for large and small taps respectively.

I would also suggest making a concave centre in the back of the tap follower,  as you can then drive it with a standard tailstock centre as supplied with your lathe, instead of needing the elaborate holding device that is shown in your example picture.

That's great to hear that you are planning to get a mini lathe.  If I may make a suggestion about that,  I would recommend that you buy the biggest lathe that you can fit into the space you have available.  

The reason I suggest this is that the tooling you will eventually buy to go with the lathe will cost the same regardless of the lathe being small or large,   and the tooling will cost at least twice as much as the basic lathe did,  so there will be very little difference in cost over the long term,  but,  if you have a small lathe,   you will be constantly frustrated by its limitations.

I have a 10 inch (swing diameter) Chinese engine lathe which came fully loaded with accessories, and cost less than an equivalent 3 inch Sherline lathe,  while being much more versatile.

You can make small things on a large lathe,   but you can't make large things on a small lathe.

I also have a 90 year old Webster Whitcomb watchmaker's lathe for small work.   It still works well,  but accessories are very expensive and almost impossible to find. 

Please feel free to send me a PM if you want to chat about your lathe plans,  or hear about any of the issues (and mistakes) I have had with mine.

 

Thank you for the awesome reply!

I am very familiar with Quinn! I have watched so many of her videos. They are my often go-to while I am in bed before I sleep.  I do like the idea of a concave centre on one end and making it reversible but I don't actually know how I would machine that! I know drills don't produce flat bottomed holes but surely there's more to it than just drilling a small hole on one end?

I am not following (heh) what you mean by putting a concave centre in the back of the tap follower. So I would have the tailstock, then my follower supported by that centre, then my tap, then my work? I feel like it would be hard to get everything straight balanced like that. My idea is to just throw it into the jacobs chuck until I have the confidence and motivation to make a MT2 shaft to fit directly into the tailstock itself.

As for which size lathe to buy, I know I am going to be limited by my 7 X 14 I am planning on purchasing but that really is all the space I have. In fact, I don't even have that space which is why I currently don't own one. I've been talking to my husband about buying a new shed and putting it in there. I have literally nowhere else to put it. I would love a Colchester lathe and a Bridgeport mill etc but that's just not going to happen. Also, I do not think anything else will be in my budget at the moment. I have been putting off buying a lathe because I flick from hobby to hobby. I struggle sticking with one thing for a long period of time and it annoys me so much.

Thank you again for your response!

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12 hours ago, Sophie said:

I do like the idea of a concave centre on one end and making it reversible but I don't actually know how I would machine that! I know drills don't produce flat bottomed holes but surely there's more to it than just drilling a small hole on one end?

The tool for making one is called a centre drill.  A small set of those is one of the earliest "must have" accessories you will need.   The drill has a narrow pilot point,  followed by a tapered cutting edge that makes a cone-shaped hole that matches the taper on lathe centres.  (I think that's 60 degrees included angle.)  This ensures that you have a bearing surface with good concentricity.   See picture.

1119337009_centredrillsetharlingen.thumb.jpeg.200316443c3967e9334545285b6bfb59.jpeg

Small taps often have a tapered point,  rather than a concave centre,  so they would run in the concave end of your tap follower if you make one.  To cut the concave centre, you would just use one of these centre drills in your Jacobs chuck while rotating the tap follower tip in your headstock chuck.

12 hours ago, Sophie said:

I am not following (heh) what you mean by putting a concave centre in the back of the tap follower. So I would have the tailstock, then my follower supported by that centre, then my tap, then my work? I feel like it would be hard to get everything straight balanced like that. My idea is to just throw it into the jacobs chuck until I have the confidence and motivation to make a MT2 shaft to fit directly into the tailstock itself.

Your Jacobs chuck will work fine for the task.   The main advantage I can think of for using the tailstock centre instead is that it probably takes up less space along your lathe bed than the Jacobs will,  so maybe if one day you are wanting to tap a slightly larger part that you can't fit between your 4 jaw chuck and your Jacobs chuck,  using the MT2 dead centre instead might buy you another inch or two of clearance.  It's probably not important,   but very easy to add the centre "just in case" when you have the part already set up in the chuck while you are making it.

12 hours ago, Sophie said:

As for which size lathe to buy, I know I am going to be limited by my 7 X 14 I am planning on purchasing but that really is all the space I have. In fact, I don't even have that space which is why I currently don't own one. I've been talking to my husband about buying a new shed and putting it in there. I have literally nowhere else to put it.

A home machine shop can never be big enough 😄.    I have a 20x20' air conditioned workshop,  and there are still some machines that I want,  but have not bought,  because I can't fit them into the remaining floor space.  I'm amazed at how well "Clickspring" can work with his two lathes and a milling machine in the tiny room that he has.  I like to be able to walk around the sides and back of the mill and the lathe in order to work on them,  fit attachments and so on.

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On 11/19/2023 at 1:01 PM, Sophie said:

I believe this counts as a geeky nerdy project? Please honk at me @gldenwetgoose if it doesn't!

I am planning on buying a mini lathe in the near future, once I have somewhere suitable to put it really, but I have already started designing parts for it! The very first thing I have designed (and likely needs some tweaking) is a tap follower. For those who do not know, one end of this device goes into the back of the lathe and the pointy bit is spring loaded and goes into the little hole at the back of a tap. This allows me to keep the tap perfectly straight while cutting threads, and the spring means I don't have to constantly wind out the tailstock with every revolution. Super handy!

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Here is my design. It's basically a hollow tube with a plunger inside, a sharp tip to go into the tap, a spring at the other end and a cap to stop everything falling out. I might make the body out of aluminium with a brass cap for style points, and I will likely make the tip out of steel just for longevity. There is a small groove cut into the tip to indicate when I have ran out of travel as a reminder to wind in the tailstock a little more. This just fits into the drill chuck (which has the benefit of being able to be used in anything with a drill chuck) but once I get more experienced I might make another with a Morse Taper 2 that fits directly into the tailstock.

562814199_follower1.thumb.PNG.b9c29cd1016e6a476def903945e2f6a9.PNG

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If you have made it this far without falling asleep out of sheer boredom, I thank you!

I could make use of that!   It is so easy to go off line when tapping a thread.   I don't have anything fancy.  I just put the tap in the tailstock and rotate the headstock chuck but leave the clamp loose on the tailstock so it slides along as the tap pulls into the work piece.

 

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  • 4 weeks later...
4 minutes ago, gldenwetgoose said:

I don't think I've mentioned it here - so now's a good point.

Some 7+ years ago my son was learning guitar.  I'm not musical at all, but a large part of my friends and acquaintances circle were all playing in bands.  I decided on a little side project of my own to 'aid' his enthusiasm.

That geeky project was a valve guitar practice amp...  Only about 2 Watts of power or so, it doesn't need much.  Design has kept in line with classic amps of the '50s & '60s so components on a tag board rather than a modern PCB.

Last night we had some friends visit, and in an attempt to stop the young son being bored, we dug out son's cheap electric guitar and this amp.  It hasn't been used for a few years and one of the curious features of a valve amp - over an hour or so of use, was just sounding better and better.   Like it was waking from it's slumbers.

 

The basis of the amp is a kit from a German company which wasn't over cheap.  But like a lot of projects, that's not the point.   The only silicon in it is a compromise in the power supply board with four discrete diodes forming the bridge rectifier, all the actual amplification being valves.  Four controls are Drive (the preamplifier which can be low for clean tones, or turned up for overdriven distortion), Bass, Treble and Volume.

The rest of the product is too distictive to show here (sorry).   It's built onto an uncycled bedside table.  The lower portion houses an 8" Celestion guitar speaker (10" would have been preferred but wouldn't quite fit).  There's then a shelf with this chassis mounted on it.  And the top has a carry handle.   The rear has a black mesh grille and the whole item is covered in (son's choice) vibrant blue snakeskin leatherette fabric.  My cherry on the top though was getting a sheet of perspex engraved with the knob functions and edge lit with blue LEDs - so the light shows up their names.

Wish I could show it - but it is very unique and identifiable.   Instead, have some pictures of the work in progress.

A701D034-E974-4B67-A7A8-DA97A47D392A_1_105_c.thumb.jpeg.52da0f4647b70c8e209436fd8d1a1c46.jpeg  DBDB0C43-F5CA-40B3-A4C8-FA3C16128145_1_105_c.thumb.jpeg.a5379cb41268fb3ae538a5920aa5e634.jpeg 94AE8295-AF85-436F-802D-8871227640F0_1_105_c.thumb.jpeg.83cf0d99ddf3ee748ab28a5e90601d0d.jpeg AE1103AC-5114-4F36-B228-59D6811AD198_1_105_c.thumb.jpeg.2a7722413b358444c751cdb3478a5e52.jpeg 154DF7C9-A06A-4971-BB80-5EA7FB369081_1_105_c.thumb.jpeg.803a2816614e25edd203dad6ced7a953.jpeg

Awesome craftmanship! and I love that it is still getting some use. You should be really proud of it.

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  • 1 month later...

It's not a geeky, nerdy project, but it's a bit geeky / nerdy I guess. I am feeding the cold birds this winter, and filling the bird bath for them. And the Mpemba effect always pops into my head in this sort of weather. It's the counter-intuitive thing about warm water freezing faster than cold water in some conditions. Really weird: https://en.wikipedia.org/wiki/Mpemba_effect 

Edited by Kupar
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Not my project,  but I wish it was.  I've always wanted a pinball machine, but now I have modified that want, specifically to a 1970s mechanical pinball machine.  

I absolutely loved these two videos, that explain the relay logic of mechanical pinball in detail. 

I actually dabbled with relay logic myself once. In 1975, when I was in high school,  I designed and built a "who's first" answer buzzer system. It was intended to be used for training the school's TV quiz show team.   Unfortunately, it didn't work very well,  as my design didn't compensate for momentum in the relay solenoids,  so it would light up for two contestants if their button presses were very close together.

It was particularly fascinating to see how,  in the first of these youtube videos, the pinball engineers designed the circuit to compensate for some of the physical limitations of mechanical switches.

I want one!

 

 

A huge amount of engineering know-how went into making these machines robust and reliable enough that they could be left unattended in the local chip shop or milk bar,  and still work all day every day.  I am impressed!

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3 hours ago, likesToLick said:

Not my project,  but I wish it was.  I've always wanted a pinball machine, but now I have modified that want, specifically to a 1970s mechanical pinball machine.  

I absolutely loved these two videos, that explain the relay logic of mechanical pinball in detail. 

I actually dabbled with relay logic myself once. In 1975, when I was in high school,  I designed and built a "who's first" answer buzzer system. It was intended to be used for training the school's TV quiz show team.   Unfortunately, it didn't work very well,  as my design didn't compensate for momentum in the relay solenoids,  so it would light up for two contestants if their button presses were very close together.

It was particularly fascinating to see how,  in the first of these youtube videos, the pinball engineers designed the circuit to compensate for some of the physical limitations of mechanical switches.

I want one!

 

 

A huge amount of engineering know-how went into making these machines robust and reliable enough that they could be left unattended in the local chip shop or milk bar,  and still work all day every day.  I am impressed!

I have watched the first video and I agree - it is just wonderful. I love electromechanical systems on this scale - things you can see (I love the idea of MEMS too, but they are aren't so easily demonstrated, are invariably just a component within a bigger digital electronic system, and don't make such pleasing clunking sounds 🙂).  The presenter is clear and engaging so we'll forgive that the script is somewhat cheesy in places 🙂 

A lovely find - thank you for sharing.

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  • 2 weeks later...

I'm considering building an intercom to connect upstairs with downstairs in the house K and I are moving to shortly (fingers crossed). We will have neighbours whose house joins on to ours, and over the last 20+ years while living in a detached house we've become used to shouting loudly to each other when in different rooms - something we probably ought to not do in future.

I could install a front-door type unit 'off the shelf' but where's the fun in that? I found a neat circuit for a hands-free, always-on wired intercom that looks about right for my limited level of ability.

https://www.redcircuits.com/Page78.htm

But I don't want it always-on. And I don't want it battery powered either. Rather, I want the whole thing to be powered by a 9Vdc supply at one end, with the ability for either unit to switch the power on when communication is needed, and off when it's not. And a means of seeing when it's on or off.

So, friends with electrical / electronics expertise, will this refinement work? I know it looks like I'll end up running a screened wire for the audio and a separate 4-core cable for the power / switching, but I don't think that matters.

 

Power.png

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3 minutes ago, Kupar said:

I'm considering building an intercom to connect upstairs with downstairs in the house K and I are moving to shortly (fingers crossed). We will have neighbours whose house joins on to ours, and over the last 20+ years while living in a detached house we've become used to shouting loudly to each other when in different rooms - something we probably ought to not do in future.

I could install a front-door type unit 'off the shelf' but where's the fun in that? I found a neat circuit for a hands-free, always-on wired intercom that looks about right for my limited level of ability.

https://www.redcircuits.com/Page78.htm

But I don't want it always-on. And I don't want it battery powered either. Rather, I want the whole thing to be powered by a 9Vdc supply at one end, with the ability for either unit to switch the power on when communication is needed, and off when it's not. And a means of seeing when it's on or off.

So, friends with electrical / electronics expertise, will this refinement work? I know it looks like I'll end up running a screened wire for the audio and a separate 4-core cable for the power / switching, but I don't think that matters.

 

Power.png

Oh - and I won't bother with the muting switch in the main circuit.

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4 hours ago, Kupar said:

I'm considering building an intercom to connect upstairs with downstairs in the house K and I are moving to shortly (fingers crossed). We will have neighbours whose house joins on to ours, and over the last 20+ years while living in a detached house we've become used to shouting loudly to each other when in different rooms - something we probably ought to not do in future.

I could install a front-door type unit 'off the shelf' but where's the fun in that? I found a neat circuit for a hands-free, always-on wired intercom that looks about right for my limited level of ability.

https://www.redcircuits.com/Page78.htm

But I don't want it always-on. And I don't want it battery powered either. Rather, I want the whole thing to be powered by a 9Vdc supply at one end, with the ability for either unit to switch the power on when communication is needed, and off when it's not. And a means of seeing when it's on or off.

So, friends with electrical / electronics expertise, will this refinement work? I know it looks like I'll end up running a screened wire for the audio and a separate 4-core cable for the power / switching, but I don't think that matters.

 

Power.png

Just to check my understanding - the plan is that there'll be a switch on the upstairs unit, and a switch on the downstairs - so flicking a switch on either end unit will turn on (if off) or turn off (if on).   The LED on each end will show the status.

On that basis, it looks that power to Unit 1 (on the right) will be provided downstream of that switched arrangement - next to the unit 1 LED and resistor.   But Unit 2 is always going to be powered, since it's directly across the supply.  Instead if you powered Unit 2 from the supply after the switch - by the Unit 2 LED and resistor you'd save on having the unit powered continuously.

Other than that - do you want some sort of chime or call buzzer?  Or just switching on the unit and talking?  I'm guessing the circuit is aimed at the sort of door intercoms you get, where the microphone has fairly low sensitivity, so you talk directly into it and a small speaker.

 

Two other thoughts - depending on your love or loathing for Amazon Alexa, if you had two Echo devices, Echo Dot etc you can speak to Alexa to "Drop in on upstairs" or "Drop in on kitchen" etc to speak between two devices.  Depends how bothered you are about Google listening to every single word that takes place.

And unless you're moving to the flimsiest of cardboard box houses, you may find the walls more insulating than you think...

But then where's the fun in that when you could be on a geeky project!

 

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1 hour ago, gldenwetgoose said:

 But Unit 2 is always going to be powered, since it's directly across the supply.  Instead if you powered Unit 2 from the supply after the switch - by the Unit 2 LED and resistor you'd save on having the unit powered continuously.

Doh! Yes. Thanks for spotting my error and suggesting the correction 🙂 

1 hour ago, gldenwetgoose said:

depending on your love or loathing for Amazon Alexa,

Yes - I have seen that suggested, but I'm more in the loathe camp 🙂

1 hour ago, gldenwetgoose said:

Other than that - do you want some sort of chime or call buzzer?  Or just switching on the unit and talking?  I'm guessing the circuit is aimed at the sort of door intercoms you get, where the microphone has fairly low sensitivity, so you talk directly into it and a small speaker.

I had assumed we wouldn't need a separate buzzer. I hope to select mics and speakers that will give a reasonable volume at the listening end. The amplifier circuit can deliver 1 watt into an 8 ohm speaker. We'll see if that's enough at breadboard stage. If not, a buzzer refinement may be needed. 

Thank you 🙂

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