# Radius/diameter turning mode



## Scorn64 (Jan 27, 2021)

I’m a novice machinists that just ordered a new lathe. I’m starting out by adding a DRO to the lathe. (TouchDRO)

What is everyone’s opinion on using radius vs. diameter mode? Because I’m just starting out I have the opportunity to get accustomed to either. 

Is it better to view numbers as a finished amount or to just remember that the value is doubled? I know it’s six of half a dozen of another, but I just wanted the opinions of people who have used both.


----------



## Jim F (Jan 27, 2021)

Learn to use the dials first.


----------



## KevinM (Jan 27, 2021)

I would set it the same as the handwheel increments.  I have learned to love the diameter mode, which my new lathe came with.


----------



## Larry$ (Jan 27, 2021)

I use diameter because that's how the drawings & my brain both work.  I normally turn until a clean round, mic, then set the DRO so when I get to final it reads zero. Just before final I'll mic again just to be sure. If there are several diameters on one part I'll just set to diameter and put a cheat sheet where I can easily see it. Works better than my memory.


----------



## darkzero (Jan 27, 2021)

I use both. I have a lathe specific DRO display so it has a button to toggle back & forth. Some universal DRO displays do not have the radius/diameter mode button. I'm not familiar with the TouchDRO, if it doesn't have the toggle button, perhaps it's feature that may be hidden somewhere or could possibly be programmed in?

If I didn't have the toggle button, I personally would set it to radius mode. Higher resolution & it would be just like when I used my lathes before having a DRO. My current lathe has indirect dials & I prefer it that way.


----------



## Ken226 (Jan 27, 2021)

I love diameter mode.   Set so the cross slide movement toward center is the negative direction.

Take a cut, mic the diameter, the plug the measured diameter into the DRO for X.    Then, the x value on the DRO is the diameter of your part.     As you get close, you can still take measurements and light cuts to hit tighter tolerances.

If the tolerances aren't tight, just take cuts until the DRO displays the diameter you want to hit.


----------



## Scorn64 (Jan 27, 2021)

I’m getting a LMS 5100 so the dials will be off a little in imperial. The thought was it wouldn’t matter that the pitch of the lead screws was metric when using a DRO. The DRO does have a button to turn from one mode to the other.


----------



## Masterjuggler (Jan 27, 2021)

It's entirely about what makes more sense to you. Personally I also suggest you turn it off for now and learn to use the dials. It gives me a much better feel for what's going on when I can see the dials smoothly turning rather than some abstract number on a display. It will also teach you to sneak up on a measurement instead of relying on the readout. 

A lot of manual lathes have dials that read the diameter, and a lot have dials that read the radius. Mine reads the diameter, so it's what I'm used to.


----------



## Ken226 (Jan 27, 2021)

I agree with regard to learning the dials first.  I just got my first DRO a year ago.  Used dials for a decade and a half.   It's like stickshift vs Auto.  Learn stickshift first and you'll be able to drive nearly anything.

My first lathe was all metric.  .05mm handwheels.  I spent my first 5 years converting everything inch into mm before taking cuts.  Is your LMS5100 dials graduated in mm, inch or both?


----------



## RJSakowski (Jan 27, 2021)

I have a lathe with metric lead screws on the cross feed, the compound and the tailstock and (approximate) inch dials. I installed the TouchDRO which I use in inch mode and diameter readout.  To set the x DRO, I turn a diameter and measure it with my mike and set the x axis to the measured value.  Since I work to drawings or other specifications where diameters are called out, I am set to go as long as I am using the same tool.  I will reset the DRO with each tool change.   

I did most of my machining without the benefit of a DRO so machining consists of making a cut or several cuts and measuring to verify my cut(s).  I still do this in spite of having a DRO when dimensions are critical.


----------



## Scorn64 (Jan 27, 2021)

Both, but the each mark is off by .0002 in imperial because of the lead screw pitch. I’m a software engineer for a Japanese company so I’m well versed in metric measurements, but my assumption is most of the tooling I can get here will be imperial and it is what I can visualize more easily. I’ve considered just going to all metric and be done with it though. Lol


----------



## Jim F (Jan 27, 2021)

Scorn64 said:


> Both, but the each mark is off by .0002 in imperial because of the lead screw pitch. I’m a software engineer for a Japanese company so I’m well versed in metric measurements, but my assumption is most of the tooling I can get here will be imperial and it is what I can visualize more easily. I’ve considered just going to all metric and be done with it though. Lol


you will never notice the 2% variance, and the dials are marked with 40 increments which is 1 mm per rev.


----------



## Masterjuggler (Jan 27, 2021)

Yeah, my lathe also has metric lead screws and inch dials, and I never even notice. On a 7x16 lathe, you won't be taking cuts anywhere near deep enough to lose track of your position, nor will you be taking cuts precise enough for two tenths to matter at all.


----------



## Boswell (Jan 28, 2021)

I see that a number of people suggest that you do not use the DRO initially until you have practice using the handwheels. I respectfully disagree with them. My lathe did not come with a DRO and so I did use the hand wheels first. However the DRO is such a game changer on the lathe for a part time user that I would never consider a lathe without one. Perhaps if you plan to have multiple lathes or make a profession out out of lathework learning the handwheels first is a good idea, but if you are like me and this is a part time hobby, Use the DRO from the start and don't look back.  BTW, I use Diameter mode almost all the time. This matches my drawings and my thinking but has gotten me into trouble a couple of times.


----------



## macardoso (Jan 28, 2021)

I use diameter mode 90% of the time and radius when I have a print that calls out a groove depth.


----------



## Scorn64 (Jan 28, 2021)

I’m nearing retirement, so I’m not looking to do anything except enjoy the experience. In my job I automate large mining equipment so I’m very use to a digitized experience. I don’t want CNC (that’s too close to just being my work) but I’ll use the DRO. More than the discussion here I like that it ignores the slop in the carriage and makes rounding errors from measurement systems much smaller. With that said I understand you have to know the physical equipment (limits, quirks) in order to be able to use it effectively/safely. The main thing for me was; is it a mistake to deal with diameter instead radius. It seems most like dealing with diameter. I don’t have my lathe yet, but I think it’s dials are radius.


----------



## Scorn64 (Jan 28, 2021)

I hadn’t thought about needing to turn diameter mode off on a non diameter. Hopefully I can apply diameter mode to a single axis and not others in TouchDRO. I would think so if it’s use on lathes much. Needing to remember to turn it off would probably make me not want to use the mode.


----------



## macardoso (Jan 28, 2021)

Scorn64 said:


> I hadn’t thought about needing to turn diameter mode off on a non diameter. Hopefully I can apply diameter mode to a single axis and not others in TouchDRO. I would think so if it’s use on lathes much. Needing to remember to turn it off would probably make me not want to use the mode.


You should be able to apply it axis by axis. You set it up once and leave it there.


----------



## Masterjuggler (Jan 28, 2021)

I'd bet your lathe will come with diameter dials. Really it doesn't matter, as long as you get used to it. 

That the DRO ignores backlash is definitely something you need to keep in mind. There is no way you'll ever get rid of the backlash in the leadscrews, not being high quality ballscrews or anything. If you back off the cross slide, the DRO won't show you the backlash unlike the dial, so you need to remember to turn the dial the right way before taking a cut.


----------



## Scorn64 (Jan 28, 2021)

The old Sherline that I’m coming from doesn’t allow you to zero out the dial. It can be a pain moving in and out and dealing with backlash and where you need to be. I’m looking forward to being able to see fairly exact values based on actual movement.


----------



## Masterjuggler (Jan 28, 2021)

More thoughts from my previous post: Even if you decide to go with the DRO straight off the bat, just don't fully trust it and stick with sneaking up on a measurement in the beginning. The thing about the lathe you bought is there are many spots for it to move during a cut. It's not very stiff so the cutter will flex backward slightly (happens on any lathe but more pronounced on a small 7x16). It doesn't come with the best chuck to put it lightly, so the work piece moving is possible. I guarantee you the headstock won't be perfectly aligned and the bed will be slightly twisted, I just fixed that on mine. The screws it uses to hold everything together may be stripped out from the factory.

Basically, things are likely to move around until you get it all sorted out and can trust it to hold the position the DRO is telling you.

Also, the dials on that lathe have an internal friction spring to keep them in place until you want to zero them, then you can just turn them manually while holding the handle in place. It's pretty easy if you ever felt like using them.

To be clear, no one who recommends dials first is bashing DROs. They're damn useful.


----------



## Jim F (Jan 28, 2021)

Boswell said:


> I see that a number of people suggest that you do not use the DRO initially until you have practice using the handwheels. I respectfully disagree with them. My lathe did not come with a DRO and so I did use the hand wheels first. However the DRO is such a game changer on the lathe for a part time user that I would never consider a lathe without one. Perhaps if you plan to have multiple lathes or make a profession out out of lathework learning the handwheels first is a good idea, but if you are like me and this is a part time hobby, Use the DRO from the start and don't look back.  BTW, I use Diameter mode almost all the time. This matches my drawings and my thinking but has gotten me into trouble a couple of times.


I will never put DRO on my current lathe, I use the dials and dial indicators and it works fine for me.


----------



## Scorn64 (Jan 28, 2021)

Masterjuggler said:


> More thoughts from my previous post: Even if you decide to go with the DRO straight off the bat, just don't fully trust it and stick with sneaking up on a measurement in the beginning. The thing about the lathe you bought is there are many spots for it to move during a cut. It's not very stiff so the cutter will flex backward slightly (happens on any lathe but more pronounced on a small 7x16). It doesn't come with the best chuck to put it lightly, so the work piece moving is possible. I guarantee you the headstock won't be perfectly aligned and the bed will be slightly twisted, I just fixed that on mine. The screws it uses to hold everything together may be stripped out from the factory.
> 
> Basically, things are likely to move around until you get it all sorted out and can trust it to hold the position the DRO is telling you.
> 
> ...


Not to get off the discussion, but do you have a recommended design for a carriage stop on this lathe? This not being there bothers me most on this machine. I don’t like the idea of engaging the feed lever to hold it. It seems like that wouldn’t be very solid and at least would cause unneeded wear.


----------



## Jim F (Jan 28, 2021)

Scorn64 said:


> Not to get off the discussion, but do you have a recommended design for a carriage stop on this lathe? This not being there bothers me most on this machine. I don’t like the idea of engaging the feed lever to hold it. It seems like that wouldn’t be very solid and at least would cause unneeded wear.


Carriage stop or carriage lock ?
Both are available from LMS.





__





						Search For... - LittleMachineShop.com
					

The premier source of tooling, parts, and accessories for bench top machinists.




					littlemachineshop.com


----------



## Masterjuggler (Jan 28, 2021)

Here are a few blogs with things to get you started: https://www.gadgetbuilder.com/index.html http://www.mini-lathe.com/

Personally for a carriage stop I 3d printed this one: https://www.thingiverse.com/thing:1860212
It works quite well, though I normally use a dial indicator on the carriage when turning to a shoulder and just manually stop it at zero. For facing operations you don't want a stop anyway, but a carriage lock. There's info for carriage locks in both blogs. I usually keep my lock semi-tight because it makes the whole thing less likely to chatter.

For reference, I have the horrible freight 7x14 mini lathe, so a step down from yours. One thing you may not find in those blogs is a heavy base for it, which I made here: https://www.hobby-machinist.com/threads/cast-concrete-lathe-base.85600/ This helps tremendously with reducing bed twist and adding mass to reduce chatter.

There are many, many things you can do to upgrade this lathe without having to buy more parts. You should be under no illusion, if you want to get the full potential of this lathe, you WILL be modifying it, quite a lot. I totally gutted the electronic system and put in a 3ph motor with VFD, 3d printed a herringbone gearbox for the head, scraped in the bed and carriage, got a 4-jaw chuck, and a bunch more. It's all part of being a hobbyist.

EDIT: There was a third blog I was looking for, but it seems to have gone down recently. Here it is on the waybackmachine: https://web.archive.org/web/20200212043904/http://www.toolsandmods.com/lathe


----------



## Scorn64 (Jan 28, 2021)

Jim F said:


> Carriage stop or carriage lock ?
> Both are available from LMS.
> 
> 
> ...


Sorry, carriage lock. 
They are currently out and I tend to want to make items like that myself unless they are dirt cheap.
The design needed for it may require a mill so I may not have a choice though.


----------



## Scorn64 (Jan 28, 2021)

Masterjuggler said:


> Here are a few blogs with things to get you started: https://www.gadgetbuilder.com/index.html http://www.mini-lathe.com/
> 
> Personally for a carriage stop I 3d printed this one: https://www.thingiverse.com/thing:1860212
> It works quite well, though I normally use a dial indicator on the carriage when turning to a shoulder and just manually stop it at zero. For facing operations you don't want a stop anyway, but a carriage lock. There's info for carriage locks in both blogs. I usually keep my lock semi-tight because it makes the whole thing less likely to chatter.
> ...


Thank you. I hadn't seem this site before.
I mainly bought this lathe in order to be able to upgrade it. I considered a PM lathe. My fear was I buy an expensive (to me anyway) lathe and then it sets because I can't think of anything to make. With a cheaper one I can at least tinker with the tool itself. (I enjoy this also)

I hadn't though about a 3D print being strong enough for a stop? I have a printer (Sapphier S, another cheap tool that I brought up to good). I'll have to try this.


----------



## Masterjuggler (Jan 28, 2021)

Scorn64 said:


> I hadn't though about a 3D print being strong enough for a stop? I have a printer (Sapphier S, another cheap tool that I brought up to good). I'll have to try this.


Well I wouldn't 3d print an entire lathe, but it's certainly useful if used properly lol. The carriage stop is such a short and stubby thing, there's nowhere for it flex. I printed a rack for my tool holders, drill chucks, chuck keys, etc. The headstock gears I printed solid out of nylon, the tool holders out of standard PLA. It's another tool in my shop, used when appropriate.


----------



## Scorn64 (Jan 28, 2021)

Masterjuggler said:


> Well I wouldn't 3d print an entire lathe, but it's certainly useful if used properly lol. The carriage stop is such a short and stubby thing, there's nowhere for it flex. I printed a rack for my tool holders, drill chucks, chuck keys, etc. The headstock gears I printed solid out of nylon, the tool holders out of standard PLA. It's another tool in my shop, used when appropriate.


I've seen on YouTube where people 3D printed change gears. I may try it to see if it works, but I don't know that I would trust the gears? Have your headstock gears held up?


----------



## Masterjuggler (Jan 28, 2021)

Scorn64 said:


> I've seen on YouTube where people 3D printed change gears. I may try it to see if it works, but I don't know that I would trust the gears? Have your headstock gears held up?


Yeah, I made a post about it here: https://www.hobby-machinist.com/threads/mini-lathe-headstock-herringbone-gears.85854/

Much stronger than the stock plastic gears, and much quieter because they aren't spur gears. Honestly my main reason was the noise, I couldn't stand the whine the spur gears made. I've stuck them in low gear and tapped 1/2-13 and taken 50 thou cuts (25 radius) in 2" diameter 12L14 steel with those printed gears.


----------



## RJSakowski (Jan 28, 2021)

Scorn64 said:


> I hadn’t thought about needing to turn diameter mode off on a non diameter. Hopefully I can apply diameter mode to a single axis and not others in TouchDRO. I would think so if it’s use on lathes much. Needing to remember to turn it off would probably make me not want to use the mode.


The DIA/RAD function can be toggled at any time.  If your zero is set at the spindle axis, the displayed values will reflect the actual diameter or radius.  On my TouchDRO, the function only applies to the x axis although it may be possible to enable it for other axes in the Settings menu.  My TouchDRO is several years old and the functions may be different on newer versions.  The answer man is Yuriy (@ycroosh) as he is the designer/of the TouchDRO.


----------

