AL320G and HXX GCS900-3D - Lathe DRO Setup

[joco-nz]

This series of posts will show setting up a Hafco AL320G with a 3 axis DRO. The linear scales are Dalco low profile scales and an HXX GCS900-3D display unit.

The linear glass scales just "do the business" where as the challenge is in the display unit. The GCS900-3D is not an expensive unit and from what I have seen it seems to be a reasonable option for the hobby user. My unit cost NZD135 delivered to my door.

Hopefully these videos will give some ideas and save anyone using these units some time.

[ame]https://www.youtube.com/watch?v=PIfvKATDJag[/ame]
EDIT: I have been in some conversation with HXX and they have told me to use DISP 7 not DISP 8.

[ame]https://www.youtube.com/watch?v=ZkgP44dbsQw[/ame]
[ame]https://www.youtube.com/watch?v=ca8dJNJRWK8[/ame]

Next up will be some installation notes and pics.

Cheers,
James.

 

[joco-nz]

One of the insights from my investigations so far is that if you want to use the Taper Measurement function you need to consider the following in your setup.

While a little mind bending (for me at least) the lathe's long axis (that which the saddle travels on) is considered Z or more correctly Z1 and the cross slide is X. Cool.

The Top Slide (Compound) is normally considered Z2. 3 axis lathe DROs usually have a feature to combine the measurements of Z1 and Z2 into a single Z measurement. Clearly the assumes you have the Top Slide facing in the same direction of travel as the Saddle.

SO, how does that relate to a multi function DRO? The DRO has X, Y and Z axis. X is mapped to the Cross Slide. And on first blush you would map
Z to the Saddle (Lathe Z1) and
Y to the Top Slide (Lathe Z2).

HOWEVER the Taper measurement function takes is measurements off X and Y. This means you will have very limited travel along lathe Z2 for your taper measurement. Not necessarily the end of the world but something to consider when thinking about how you map your DRO axis to the Lathe's logical axis.

Edit on the edit: If you link Y and Z so that they act as combined Z then having the lathe Z on DRO Y should all work out correctly as it will be combined to the Topslides value which is on DRO Z resulting in a combined Z reading, which is what you normally want and you have the easy to move Lathe Z on the DRO Y for the taper function to work ok.

Cheers,
James.

 

[V22]

For the benefit of anyone that comes across this thread hunting for GCS900 troubleshooting, if you get "DROERR" or the like (random characters etc..) and really unreliable display then you should check the power supply. These units have a mains transformer circuit under the cover. Mine was putting out a high 4v. The unit needs more than that to run. Some Chinese power supplies like the one within the DRO have a pot to allow you to tune the output. Unfortunately the one in my GCS900 did not. I had to replace the power board with a cheap 5v PSU with pot. Since tuning to 5.2v the DRO has been perfectly stable for months now. Incidentally I replaced the main board prior to hunting the voltage and that made no difference. Definitely a dodgy power supply. Fortunately a super easy fix. What's more the aliexpress seller paid for the parts without any argument.

Another thing to note is that I have another Chinese DRO from 5+ years ago. It was purchased from the dro pros. It looks rather diffferent package wise but the software is exactly the same. The menus are all the same. The aliexpress one was about half the price of the one I purchased earlier. That said, the one that was twice the price worked flawlessly out of the box for the last 5 years..

 

[joco-nz]

Making progress on the Z1 axis.

Template to make out the interference area for the lathes back shield.

I needed to make a quick tool to act as a drilling and tapping guide. However got a little carried away and instead of just doing it for the M5 I needed I ended up making this little guide for M2.5, 3, 4, 5, 6 and 8.

The drilling tapping begins

I needed to make some spacers to hold the scale ~3mm off the lathe casting. So some 3mm Ali flat bar to rescue

Scale mounted and DTI setup to test for alignment. I finally managed to get the scale aligned in the vertical and horizontal to within 0.05mm over its length of slightly over 700mm.

Cheers.

 

[joco-nz]

Finalising the Z1 axis.

I needed to create a wide bracket with slotted holes to link the saddle to the aliuminium angle that bolted to the scale reader. I wanted something 5-6mm thick but only had 3mm Ali sheet. So having an ACDC welder I cut two sheets and plug welded ito all togther. Then surfaced things a bit. In hindsight I should have just left things alone. But in a burst of enthusiasim I was trying to make things better, instead I just created work for myself.

The plate in place linking saddle to scale reader.

You can see the linkage and how the nuts stick out. This created an interference problem with the protetctive guard. A cunning suggestions from a friend (Bruce) had me creating a countersink for the nuts.

Here is said countersink. This means no need to get a spanner to tighten the nuts.

And the finished install of Z1. Pretty happy with it so far.

Cheers,
James.

 

[joco-nz]

Starting the X axis and trying to figure out how best to mount it.

Showing the mounting back plate that came with the scales. Its temporarily secured here.

A couple of views of the mounting position.

Here is where I think I will place the mounting holes. They can go into lots of "meat" in the cross slide.

Cheers,
J.

 

[rodw]

Ah, takes me back. My DRO has not skipped a beat since I did it to my AL320G 2.5 years ago.

I would revisit the proposed mounting points. I seem to remember that in amongst playing with 3D printers, you also have a mill at your disposal. Here's the backing plate I made to mount the scale.

This let me attach it much further back and still retain access to the gibs adjustments where its cut away.
Sorry, I did not take many photos, I just got in and got it done. With hindsight it was pretty simple really.

Read head mount.

And with the cover on. The backing plate is 6mm thick ally. The cover is held on with 2 M3 screws and I have to remove it to get to the oilers.

Sorry I don't have a pic of mounting the backing plate and I can't see the screws which must be hiding behind the scales but I've not touched this since the day it went in....

If I told you how much paying work I've smashed out with this lathe in the last week or so, you would not believe me. I think the tally is over 20 metres of plastic rod down to 50mm long parts. While mine looks well used, it is still very accurate and delivers a real nice finish.

 

[joco-nz]

This is the mounting plate that is also part of the cover assembly that came with the scales. It's mounted so that with the cover in place said cover will be just slightly under the top of the slide casting.

From this photo it should be visible that there is still good access to the gib adjustment screws.

Cheers,
J

 

[rodw]

Joel, My concern is the large overhang unsupported. Could you make a mounting block or bracket that you could bolt the scale to at the rear end? My thought that it would be attached to the top surface of the top slide and allow the scale mount to be bolted onto the side of it.

 

[joco-nz]

The bar in the picture is the support. It’s a 7mm by 25mm strip of 6061 ali. Plan is to secure it in 3 places with M4 cap screws. Then I mount the scale to this bar.

Cheers,
James.

 

[joco-nz]

Working on the cross slide tonight and got the 3 holes drilled 6mm deep and tapped M4.

Test fits with the mounting bracket and cover before moving on to next stage which is drilling the required holes in the mounting bracket.

 

[XD351]

While you have the cross slide of you may want to drill and fit 2 button oilers so you can oil the top of the dovetails and check the cross slide feed nut as mine was not flat where it makes contact with the cross slide and began to rock as the slide was wound in or out , this eventually wore the thread out .

 

[joco-nz]

While you have the cross slide of you may want to drill and fit 2 button oilers so you can oil the top of the dovetails and check the cross slide feed nut as mine was not flat where it makes contact with the cross slide and began to rock as the slide was wound in or out , this eventually wore the thread out .

The nut looks ok and i have adjusted it to pretty much eliminate any perceptible backlash.

On the oilers, I’m probably being thick, do you mean oil ports that will drop into where the gibb and its opposite side “squeeze” the dovetail? As distinct to the existing ports that oil where the slide runs on?

Cheers,
James.

 

[XD351]

Yes so the gib and opposite side dovetail get some oil , i have just done this to my 320 along with a new cross slide nut as my one was the older style and not adjustable .
I' m currently rebuilding it and making modifications as i go but for now it is still in a million pieces getting the paint stripped back .

 

[joco-nz]

Some more progress shots from the last week and this weekend.

Cross slide post drilling with the mounting plate drilled and mounted.

The scale in place.

Testing with the cover on. Nicely just below the surface of where the topslide will mount.

Been working on a bracket for the scale reader to be mounted to. Here is the result test mounted on the top-slide scale.

Finally a test mount on the real deal. since I have all four holes on the reader drilled into the bracker I can use two on the left side and reach up through the casting to tighten them once I have the head aligned with the mounted bracket. Then carefully take off the slide to allow the last screws to be put in place and remount it all. Should work and allow for repeatable positioning within acceptable tolerances.

Cheers,
J.

 

[joco-nz]

A small update to show the finished X axis scale.

Slide all mounted, on the backing plate, aligned to within 0.01mm on its travel, custom aluiminium block fitted to the reader and mounted to the saddle with M5 bolts. I'm still on the fence about how best to put a stop in place for the tail stock. Maybe just drill/tap for and install an M8 cap screw into the ali block bolted to the saddle. That would allow an adjustable stop and will be pretty solid.

Cheers,
James.

 

[bruedney]

I'm still on the fence about how best to put a stop in place for the tail stock. Maybe just drill/tap for and install an M8 cap screw into the ali block bolted to the saddle. That would allow an adjustable slot and will be pretty solid.
Cheers,
James.

M8??? Are you going to drive that tail stock in with a sledge hammer - M5 Bro

 

[joco-nz]

M8??? Are you going to drive that tail stock in with a sledge hammer - M5 Bro

Was thinking more about the nice large surface area the M8 cap screw has on the head. Not because it needed strength of the M8. scratch.gif

 

[joco-nz]

Started on the compound scale this weekend with most of the progress being made today.

Initial test fits of the scale to get an idea of where the best placement will be and where the reader will sit in relation to the compound.

Having figured out the placement I measured the backing plate for where I would need to make holes in the both it and into the compound. Here is the result post drilling etc with an initial fit with no standoffs.

Cover in place and starting to feel reasonably confident this is going to work out. Now remember I still need to make some standoffs as my lathe does not use tapered gibs.

The stand-offs being created. One is tapped M4 so the mounting/backing plate can be secured using the existing mounting holes in said plate. The other hole is a through hole to the tapped hole in compund.

The result with stand-offs mounted onto the back plate.

Trial fit on the compound. Everthing lined up perfectly.

These last two are the scale mounted on the compound with only the mounting block for the reader to be solved.

Cheers,
James.

 

[joco-nz]

For anyone who might be interested the scales I got are:
Z1-Axis: 600mm travel https://www.aliexpress.com/item/New...32830594556.html?spm=a2g0s.9042311.0.0.7BzZOZ

Z2-Axis: 70mm travel Using the same slim slide as the X axis from the same supplier but cut to a custom length by asking said supplier.

X-Axis: 200mm travel https://www.aliexpress.com/item/Sli...32812469530.html?spm=a2g0s.9042311.0.0.7BzZOZ