# AL-320 Lathe DRO Upgrade



## simister (Jul 5, 2015)

I am looking to install a DRO on my 320X600 AL-320 lathe (http://www.machineryhouse.com.au/L141). 

However, I am not sure if I should get a 3 axis or 2 axis as I am mainly doing small work. I have fitted up 3 axis DRO on my milling machine and now would like to update the lathe.

Any advice please.

john


----------



## Cogsy (Jul 5, 2015)

I got an email from them just this morning with discount codes valid for the next two weeks only - code DV20 gives $20 off if you spend $100 or code DV50 gives $50 off if you spend over $300. I think they're only good for the online site though.


----------



## XD351 (Jul 6, 2015)

Depends on what type of 3 axis dro you're looking at , i have the same machine with the 3 axis set up but never bothered to fit the scale to the compound slide as it was going to be a pain in the neck to do so .
The display has only two readouts as you switch between compound slide and saddle X1/X2 axis on the display .
Remember that if you use a milling type readout it wont read diameter or radius like a lathe type dro it will only give you tool travel .
Mine is an Mtech unit from the dro store .
I also have the same unit on my AL50G and wasn't that an adventure fitting that !

Ian


----------



## simister (Jul 6, 2015)

Thanks Ian,

I was going to purchase the same unit from the DRO store.  Did you only fit the two axis up on both machines or 3 axis on the AL50G.  Did you have any trouble doing the two axis on the AL320?


I am not sure if it is an over kill going for the 3 axis? What is your opinion?

John


----------



## rodw (Jul 7, 2015)

I've fitted a 2 axis DRO to my AL320G. I went with Ditron and am very happy with the quality. The price was pretty ridiculous.

The cross slide was a bit fiddly but worked out nice.






















The long feed was easy, made mounting blocks with a slight angle on them and included a setscrew to level the mounts in case I got the angle wrong. I did not use any of the included mounting hardware.


----------



## XD351 (Jul 7, 2015)

simister said:


> Thanks Ian,
> 
> I was going to purchase the same unit from the DRO store.  Did you only fit the two axis up on both machines or 3 axis on the AL50G.  Did you have any trouble doing the two axis on the AL320?
> 
> ...




The  AL320 has the 3 axis display ( really only a two axis unit that lets you switch between 2 scales ) but i never bothered fitting the scale to the compound slide as it is not something i think i will use and not worth the hassle but you may like it and for what the extra cost is may well be worth ordering the the 3 axis unit .
I usually use the carriage to machine close to the length i need then use the dial on the compound slide to nibble away the last bit and if you are having trouble with the type of dials on the machine (metric v imperial etc ) just set up a dial indicator and use that to tell you how far you have moved the compound slide .
Fitting a 3 axis system to the AL50G would be problematic with glass scales as i don't think you can get small enough ones for the compound .
With this lathe i ended up fitting the carriage scale along the front under the apron as the motor makes fitting it behind the bed difficult and i had to make some custom mounts to hang the cross slide scale off the end of the cross slide 

Ian .


----------



## XD351 (Jul 7, 2015)

Wow a triple post ! Damned ipad!
Appreciated if a kind moderator can fix please .


----------



## canadianhorsepower (Jul 7, 2015)

XD351 said:


> Wow a triple post ! Damned ipad!
> Appreciated if a kind moderator can fix please .



you can delete it yourself 
go to edit and delete 
cheers


----------



## XD351 (Jul 8, 2015)

Thanks  !
I'm used to another forum that only gives you a  limited time to edit anything .
I couldn't do this on my Ipad but once i logged in via the website it all became clear  .

Ian.


----------



## michael-au (Jul 8, 2015)

simister said:


> I am looking to install a DRO on my 320X600 AL-320 lathe (http://www.machineryhouse.com.au/L141).
> 
> However, I am not sure if I should get a 3 axis or 2 axis as I am mainly doing small work. I have fitted up 3 axis DRO on my milling machine and now would like to update the lathe.
> 
> ...



Hi
I have almost the same lathe as you,
I fitted the two axis DRO to mine, best thing i did

Brand EASON


----------



## simister (Jul 8, 2015)

Thank you all for your input and photos. I was looking at the unit from the dro store, however, I will have a look at the Ditron dro.  I think I will go for the 2 axis unit. John


----------



## simister (Jul 8, 2015)

Rod, where did you purchase your dro from?


----------



## rodw (Jul 9, 2015)

simister said:


> Rod, where did you purchase your dro from?



John, initially I saw a compact scale in a glass cabinet at Hare & Forbes and noted the brand as it was a lot more compact than  the so called compact scales at DRO store etc. 

I found Ditron on Alibaba and dealt direct. Search for Ditron DRO there. Cost was USD 370 landed back in January 2014 when the rate was good. $119 of that was DHL freight. 

I went with 150mm DC11F slimline and 600mm DC11 1 micron scales which were both under USD $70. 

The DC60-2V readout was USD $100 and they added Paypal fees of USD $15. The 150mm scale limits travel slightly. I knew that but it fitted nicely as you can see.

Much better quality than the stuff I paid $800 for for the incomplete SX3 milling kit which has a plastic readout case when Ditron is metal. Also Ditron Scale covers are superior.

When I mounted the long feed scale, I used a Ditron supplied angle bracket and a flat piece of 6mm aluminium for the read head.


----------



## simister (Jul 9, 2015)

Thanks Rod,

That is really cheap. It will be more now because of the dollar but still should be a good price. I will have a look at Alibaba and check it out. I purchased a DRO for my mill from the Drostore and I am very happy with that unit. However, they are certainly more expensive that the prices you paid.

John


----------



## rodw (Jul 10, 2015)

simister said:


> Thanks Rod,
> 
> That is really cheap. It will be more now because of the dollar but still should be a good price. I will have a look at Alibaba and check it out. I purchased a DRO for my mill from the Drostore and I am very happy with that unit. However, they are certainly more expensive that the prices you paid.
> 
> John



Thats what I thought. I figured if H&F bought Ditron scales they would be pretty good quality as they don't buy at the bottom of the Chinese market but for me, the attraction was really the extra compact scale so I figured I might as well use all their gear.


----------



## petertha (Jul 10, 2015)

XD351 said:


> i never bothered fitting the scale to the compound slide as it is not something i think i will use and not worth the hassle but you may like it and for what the extra cost is may well be worth ordering the the 3 axis unit .Ian .


 
I have a different DRO system (Newall) but I find having compound readout is very useful for much the same reasons as having it on X&Y. Yes, it is a bit more cramped & maybe doesn't lend itself to certain scales & encoder blocks offered. Newall is quite compact, but I've also seen compound installs using the typically larger offshore gear. 

Anyway, just for reference ideas, you can see my compound installation here. 
http://www.homemodelenginemachinist.com/showthread.php?t=19361


----------



## Blogwitch (Jul 10, 2015)

You might think it a bit of an overkill, but I have fitted my lathe out with 2 x 2axis units and have found the topslide and tailstock ones are indispensible if doing any high precision work.
I was lucky and my machine could take the two extra ones using medium sized scales, but for a lathe of your size, you could always use the small pattern read heads, or even high res magnetic ones.

The tailstock was a bit fiddly to do as you have to cancel out the rotation (even though only tiny) of the quill. If you don't, you can easily bend the read heads out of adjustment. It is the same when using cheapo scales on the tailstock, you must find a way of cancelling out the quill rotation.

This is how to fit one correctly to the tailstock.

http://chestermachinetools.forumchi...ilstock-7282746?pid=1286071543#post1286071543


John


----------



## petertha (Jul 10, 2015)

Timely post John. I'm doing a tailstock readout setup myself, but the el-cheapo electronic vernier style. Your detailed write up gave me some good ideas on mounting brackets & such. 

I was going down the path of making my mount plate removable to get at the spindle oiler points. I noticed you had them to, but at different locations. Maybe I missed the detail, but did you re-drill them or have some alternative lube strategy as it looks like the DRO assembly covers them up?


----------



## Blogwitch (Jul 11, 2015)

Peter,
That is the only downfall of my system, and I had to do some deep soul searching on that one.
I came to the conclusion that a quick strip down yearly, which I do as a matter of course on other parts of the machine to remove swarf/gunge etc will be good enough lube for the tailstock operating screw. The quill and home made bearing support gets a drop of ISO 32 whenever I squirt a bit into/onto other parts.
I was going to redrill new lube holes, but thought better of it.

For your type of scale mount, I would suggest you go down to the local model shop and get some linkage ball end fittings to connect the quill to the scale, they will get you over the quill rotation problem.

http://www.aliexpress.com/item/1-ki...-for-climbing-simulation-car/32376253110.html

Just a bit of threaded rod or sawn off thread from a tiny bolt between two of them makes a good linkage.

BTW, once you have done this mod, you will be amazed at just how accurately you can drill to exact depth using the tailstock.

Hope this helps


John


----------



## ICEpeter (Jul 11, 2015)

Hello John and Peter (Petertha),
I put a tailstock readout on my Myford S7 a few years ago with the goal to retain full travel of the tailstock quill. To achieve that it required a bit of surgery to the tailstock body on the mill and some epoxy to smooth out the contour but it turned out well and works great.

I include some pictures to show the modifications and hope they are self explanatory. Feel free to ask if more clarification is required.

When I modified the tailstock, I also installed Newall Micron 10 two and three axis DRO's on the Myford S7 and the Myford VME mill. Will post pictures of that later.

Peter J.


----------



## petertha (Jul 18, 2015)

Blogwitch said:


> Peter,...For your type of scale mount, I would suggest you go down to the local model shop and get some linkage ball end fittings to connect the quill to the scale, they will get you over the quill rotation problem.John


 
Finally got around to mocking up my bracket. My tailstock casting has kind of a slight tapered crown. But when I make the side ears like so, the DRO/scale is nice & square & visible, doesn't hit the turn wheel etc. The backside vertical plate has 3 threaded holes for bolts to secure it in position set-screw mode for now. I'm not keen on drilling holes quite yet.

Now the issue I think John is referring to. The barrel has a very slight amount of rotational play, I suspect from the keyway gap. Not a lot but enough that I worry if I mount the DRO assembly firm & to the barrel plate, it will probably impart torque to the extended scale & that cant be good. So yes, I see the need for some sort of 'universal joint'. 

I'm totally aware of RC ball links & all their variations. But I'm not quite clear how to mount it. The problem I see is the (ever so slightly)  rotating barrel wants to translate this into an extended arc at the mounting bracket. So for example a vertical mount bolt with a ball joint isn't really accommodating this motion? Any clarification or suggestions welcome.


----------



## petertha (Jul 18, 2015)

..the (exaggerated) motion sketch


----------



## Cogsy (Jul 18, 2015)

How about a nice fitting pin from the wood into the mounting slot? If the slot is truly perpendicular to the barrel the pin would be able to rotate slightly in either direction without putting any force on the scale. Of course the pin needs to be a nice fit to eliminate any 'backlash' in the scale though. Plus the scale would not be able to rest on the wood so would be unsupported on that end, but I can't see any way around that anyway that wouldn't put force onto the scale.


----------



## rodw (Jul 19, 2015)

Just went and had a look at my tailstock. Why don't you cut the corner off near the tip of your arrow and place a flexible piece of metal between the scale end and the front mount so it can flex to take up the rotational movement? That way there won't be any backlash. A bit of tin plate or 1.2mm aluminium would do the job. I'm envisaging this plate would be screwed to the mount on the side and the scale stays where it is.


----------



## DJP (Jul 19, 2015)

Whatever rotational motion due to sloppy keyway will only happen when the drill bit or reamer is under load. If you zero the calliper when there is load you don't have to worry about any accuracy change. You should be able to twist the chuck with one hand and zero the calliper with the other hand as a procedure to take away any error. 

I think that the calliper beam can take some twist without ill effect as long as it is well extended.

Just some thoughts to add to the mix. I am still 'old school' and don't have DRO on my machines. For the operations that I do the scales on the machine are accurate enough. Press fit, slip fit and Loctite fit are all part of my play book but not always intentional. 

These discussions on adding DRO I find interesting.


----------



## bobwho (Oct 17, 2016)

Old Post but thought I should add my AL320 mods...
My version of a Digital Caliper install, TIG welded a m5 bolt shank onto the front face of the tailstock quill so it can retract fully and eject non-tang tapers.  Made an angle shelf and bolted each jaw solid, works brilliant.  Did this before I got DRO





Like Rodw I researched first and found Ditron on Aliexpress, cannot fault them, excellent product and service.  Grabbed a 3 axis because if there was ever a problem I can interchange it with my mill drill DRO, never bothered with compound slide, just went for the 1 micron precision, giving 0.002mm reading on diameter (not that the lathe can do that sort of precision)

Cross slide attachment for DRO 160mm, I added the large cap screw to carriage mount so the tailstock wont hit it





Fitted with small scale, blocks the gib screws but at least its safe from the chuck.  I never bothered with the covers...





Simple mounting of long scale





I am currently putting it back together after changing all the bearings for SKF brand and repainting... Here I am matching the carriage to the apron on the shaper... I hated the edges not being flush... 
	

	
	
		
		

		
		
	


	




Looks much better in Charcoal Hammertone... probably wont look good for long





Where I am at now...


----------



## rodw (Oct 18, 2016)

Thanks bob, i was very interested in the tailstock setup. I always figured this was a better way to go than to try and use a 3 axis DRO and fit a huge scale on the tailstock. I have this style on my SX3 mill and I only use it for hole drilling and it is brilliant. Great to see it in action.


----------



## Blogwitch (Oct 18, 2016)

DJP,

It isn't about zeroing the scale or losing readings at all, it is about the twist imparted to a rigidly mounted scale on the scale's internal runners. They fail badly because of much lesser reasons.

That was why (and I have seen many mods done using this method) I suggested the ball joint solution, it allows the quill to rotate slightly without giving any twist force to the scale. OK you may lose a thou in measurement either way because of the swing of the swivel joint, but at least you won't be doing any damage to the scale.

I went to great lengths to get around that problem when I fitted a proper DRO to my tailstock, and didn't feel satisfied until it had been completely solved, and the way I did it kept my readings spot on.

When you do any modifications like this to a machine, you have to look for any problems that MIGHT occur because of that modification, and being blinkered into thinking it SHOULD be OK as nothing has happened yet is no way to look at it.

It might seem insignificant to yourself as it is only a few bucks worth of scale, but it isn't!!

When you are half way down drilling a critical depth hole, and the scale gives up, that is when the problems usually occur, and that is when it becomes significant.

John


----------



## joco-nz (Oct 18, 2016)

I'm finding this discussion very interesting as eventually a DRO on the lathe would be desirable. In the mean time I'll use dial indicators and digital callipers.
Keep the pictures and ideas coming!   :thumbup:


----------



## bobwho (Oct 19, 2016)

Thanks rodw 



DJP said:


> I think that the calliper beam can take some twist without ill effect as long as it is well extended.


I have found my method to handle rotation twist very well, as it is only pivoting between one bolt per jaw, and to be honest I only notice it when the quill retracts just beyond flush as the jaws close and there is still 0.1/0.2mm more to retract, you see the whole caliper shift, otherwise it has been flawless






			
				Blogwitch said:
			
		

> DJP, It isn't about zeroing the scale or losing readings at all, it is about the twist imparted to a rigidly mounted scale on the scale's internal runners. They fail badly because of much lesser reasons.


I see DJP mentioning caliper as opposed to scale, calipers are tough... and I never thought much about a scale on the tailstock, just too bulky.
As I have my HM46 quill using a glass scale, and it has rotational twist (passive tho, not load reactive as the quill isn't the spindle) I thought carefully about how to combat it (My first alignment of the lathe cross slide was off and I had very slight read counting errors so I learnt that correct angles also matter), hence some unused mounting holes on the read head bracket.




Instead of hard mounting the scale and making an arm for the read head, I hard mounted the read head to the side of the mill and have the scale move up and down, this has helped, it still has significant rotational twist, but it is not giving me read errors, I may find it failing in the future, but I'll take the risk.  Bracketry is minimal and I get to keep my depth stop (which will be upgraded later)


----------



## Blogwitch (Oct 19, 2016)

J,

In my opinion, fitting DRO's to a model engineering machine has been one of the main steps forwards in home machining in a long time, just like fitting 3phase motors and VFD's to give infinite speed control.

Unlike what a lot of old timers think, it isn't cheating, as all it is doing is superceding earlier mechanical methods of measurement.

I have been using DRO's since the mid 80's when I was working in a model shop making prototype hard disk drives, and without them at that time, it would have been almost impossible to make to the tolerances required by just jigging and fixture holding, you would have to have made a jig or fixture for each machining operation. 
You could now do it with just a couple or three datum points from the bolted down piece part. 
I just couldn't wait for the model engineering fraternity to catch up.

When I upgraded my mill system to 3 axis, I had a spare 2 axis display head, so it was only logical to fit it onto my lathe, which already had 2 axis on there. This was at a time I was using my shop as a precision machining area, and those two extra displays made all the difference to what could be achieved.
Try to make a hundred of these steam control valves with some internal tolerances of 2 tenths. This was easily done with my lathe DRO's.








I suppose eventually four axis will become readily available for mills and lathes, until then, we have to take whatever is available. There are already 4 axis display heads out there. Maybe we can do away with scales on our handwheels eventually, I haven't had to use mine for years.

Four axis on my mill, the small one on top is a display head for the scale type I use on the quill and it doesn't require batteries as it runs from a specially designed PSU that a friend made for me.






Display heads on my lathe






The two extra bits that aren't normally fitted

Topslide






Tailstock






Please excuse the junk in the background, that is my spraymist system that had to be got out of the way while I did the DRO mods.


John


----------



## Blogwitch (Oct 19, 2016)

Bobwho,

"I see DJP mentioning caliper as opposed to scale, calipers are tough...  and I never thought much about a scale on the tailstock, just too bulky."

I wasn't referring to a glass scale, I was referring to the cheapo SCALES some people fit, which are the same as the digital scales you use for measuring.

When they are put into a stressed situation, like being twisted, they can have a dramatic failure rate. I know this because I spent a small fortune trying to keep them running on my old mill, I had to have a couple of new or repaired scales sitting in my cupboard all the while they were fitted. It was a godsend when I started using glass scales on my then new machines.

Glass scales are no more tolerant, if you can't mount them totally stress free over their whole range of movement, it is not worth bothering trying to fit them. 
I have 7 glass scales (soon to be 9) and one cheapo scale fitted to my equipment and I have yet to have one even flicker with discontent purely because I took the time to mount them correctly with absolutely no twist or deviation over their whole length of operation. It takes lots of time and effort to do it like so, but it is time well spent rather the "throw it on there and if it works, it's done" brigade. 
As far as I am concerned, it might not be a few months or even a couple of years, but it will show up bad workmanship in the end.

I might be a bit paranoid over things like this, but I do know that of all the machinery in my place since it was upgraded to mainly all new some years ago, none have never failed me, except when it was a manufacturing fault, one bearing failure (10 minute replace job) and one motor failure (new motor sent out for next day).

BTW, on your glass scale fitment, that is where you should have used a slip joint on you bottom fitting as I did on my tailstock fit, it is the only way to rid yourself of the twisting motion while still retaining your measurement accuracy.

John


----------



## Kpar (Dec 19, 2016)

rodw said:


> I've fitted a 2 axis DRO to my AL320G. I went with Ditron and am very happy with the quality. The price was pretty ridiculous.
> 
> The cross slide was a bit fiddly but worked out nice.
> 
> ...


Rod, new chap here. I also have an Al-320 G- L141 and would like to fit a2 axis DRO. It's like buying milk "too many choices". Anyway after looking at your installation my lathe maybe a bit different as there is oiling points and adjusters on the tailstock side of the cross feed. Was this an issue with your installation ?
Kpar


----------



## Kpar (Dec 19, 2016)

rodw said:


> I've fitted a 2 axis DRO to my AL320G. I went with Ditron and am very happy with the quality. The price was pretty ridiculous.
> 
> The cross slide was a bit fiddly but worked out nice.
> 
> ...


Not sure what I done before but unable to get my message so will try again.

Rodw, new chap here. I also have an Al-320 G- L141 and would like to fit  a2 axis DRO. It's like buying milk "too many choices". Anyway after  looking at your installation my lathe maybe a bit different as there is  oiling points and adjusters on the tailstock side of the cross feed. Was  this an issue with your installation ?
Kpar


----------



## Blogwitch (Dec 20, 2016)

Kpar,

You raise a very good point about items being under the read head.

When my lathe was new, it was supplied with the read head already fitted and it covered up the gib locking screw, which is definitely required if taking heavy cuts.
Luckily, my lathe has tapered gibs so those didn't come into equation, just the locking screw.

This post shows how I got around the problem, and can be used anywhere a locking device is required on a dovetail slide.

http://chestermachinetools.forumchitchat.com/post/locking-up-my-cross-slide-7284193?pid=1286083315

John


----------



## rodw (Dec 20, 2016)

Kpar said:


> Not sure what I done before but unable to get my message so will try again.
> 
> Rodw, new chap here. I also have an Al-320 G- L141 and would like to fit  a2 axis DRO. It's like buying milk "too many choices". Anyway after  looking at your installation my lathe maybe a bit different as there is  oiling points and adjusters on the tailstock side of the cross feed. Was  this an issue with your installation ?
> Kpar



Sorry for ignoring you Kpar, some of us work for a living. Yes I need to remove the cover to get to the oiling points but I watched the placement of everything so i could get to them. Every time I tke the cover off, I think of leaving it off, but its only 2 scews so I pop them back in.


----------

