Author Topic: DRO Installation on a Mill/Drill  (Read 1012 times)

Offline MJM460

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DRO Installation on a Mill/Drill
« on: January 12, 2021, 11:20:32 AM »
I have been thinking for quite a while that my next machinery expenditure should be a DRO system for the mill.

At present, I have two cheap single axis scales on the lathe, one on the saddle long travel, and the other on the tail stock quill.  While I would like one on the cross slide travel, I canít see how to do it without loosing necessary length for collet operations, which require the tailstock almost hard against the saddle which in turn is almost hard against the head stock.  So that is a future problem to solve.  But cheap and simple has been really useful, and convinced me of the value of doing even better on the mill.

On the mill, I have a single scale DRO on the quill, but none on the table.  Sometimes I set up long travel dial gauges to help with more accurate lengths and positions.  They work, but are tedious to set up and so many things collide.  A DRO is definitely called for.

The local machinery house sell a three axis kit which looks like a good compromise between the low end cheapest ones and the top quality, though I suspect that I have never seen the real top quality that a manufacturer might require.  Just as lockdown eased enough that I could travel to the store, they held their twice yearly sale, and I was able to take a couple of hours between helping with domestic chores while my wifeís wrist healed.  The one I purchased is SINO brand.  The package includes the display head and three scales to suit my mill and the bracket kit.  The two shorter scales each came with a predrilled backing plate and a nice protective cover.  The long scale also had a protective cover but no backing plate. 

I spent an hour or two in the showroom seeing how they installed the scales on the mills that come with them pre installed.  I was a bit disappointed to note that they only install the two axis kit, and resort to an independent single scale on the quill, similar to what I already have.  But that is certainly a clue that installing that quill scale is not easy to do.  It will be a challenge to come up with something neat that allows the depth stop to continue to be used.

The costs are such that it is better to buy the three axis kit with the scale, even if the scale eventually goes on the lathe, as you canít add it later if you only buy the two axis display.  So fingers crossed, I bought the three axis system which comes with the three scales and a ďuniversalĒ bracket kit.  That of course means the supplied brackets do not fit any specific mill, and I cannot see how to use the brackets provided on my particular mill, but the selection of bolts and shims will be quite useful.   The mill I have was bought some years ago.  It is labelled with the house name and the model HM-46, but it looks suspiciously like it comes from the same factory as the Grizzly.  They now sell a new model, HM-46B, which is very like the Grizzly that Stewart recently equipped with a DRO in his shop thread, and only quite small differences from my earlier model.

After some time ďlooking and pattingĒ, I have come up with a scheme that feels like it will work.  I made brackets from 6 mm thick aluminium strips and some 62 x 62 x 6 angle that I had on my shelves.  The actual machining operations to shape the brackets, along with plenty of drilling and tapping is all very simple.  For me, the biggest difficulty is the necessary freehand drilling and tapping small holes (M4) into the base casting of the machine.  I was concerned about breaking, particularly in areas where the room to try again in a slightly different location is limited.  I was able to get help from my mentor, who has more experience and a steadier hand for such tasks.  However, the arrangement I came up with might help anyone else contemplating a similar project, even if just what not to do.

My plan for this thread is to concentrate on the arrangement, and my solution to the issues which arose.  Along with a few photos.

Next time, the y- axis.

I hope this project is of interest to someone.

MJM460

The more I learn, the more I find that I still have to learn!

Offline derekwarner

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Re: DRO Installation on a Mill/Drill
« Reply #1 on: January 12, 2021, 12:07:11 PM »
Following on with interest MJM  :happyreader: .. .....& learning.......

Derek
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Offline propforward

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Re: DRO Installation on a Mill/Drill
« Reply #2 on: January 12, 2021, 03:27:23 PM »
Very nice MJM, I shall be following along too!

I found that a relatively cheap right angle head for my hand drill was really useful to make holes on the backside of my mill table. It was about $25, so not silly expensive, and it has since been useful for other projects as well.

My DRO has made a huge difference - it turns out that my backlash was a lot more than I had realized, so I had inaccuracies of Ī0.02 and more in my parts.
« Last Edit: January 12, 2021, 03:31:06 PM by propforward »
Stuart

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #3 on: January 12, 2021, 11:21:45 PM »
This all feels quite familiar!

I love your dry observation that a 'universal' bracket doesn't actually fit on anything...  :)

In my case there was no obligation to buy 3 scales as they were sold individually. I bought my DRO kit with the mill and knowing that the mill has its own small inbuilt DRO on the quill I decided not to reinvent that particular wheel given how notoriously fiddly fixing a scale to the z axis can be. Not as good and not as nice as a proper 3 axis setup going through the display, but it works.

I too was trepidacious (is that a word?) about going into the main casting with a hand drill, but it was surprisingly easy. I find cast iron to be an extremely forgiving material. That said, I wasn't too worried about things going a little out of true due to squint holes as I had designed quite a bit of adjustability into my setup.

Following along...

 :popcorn:

Offline MJM460

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Re: DRO Installation on a Mill/Drill
« Reply #4 on: January 13, 2021, 02:33:16 AM »
Hi Derek, good to have you following along.  I hope you are getting some quality shop time with the current restrictions and staying away from those hot spots.

Hi Propforward, I do also have one of those right angle attachments.  Very useful in awkward places.  I have planned to try that if I have to drill the table where the column will obstruct the drill, but if I can locate the holes in the table further apart, it will just about be possible with a bit of contortion.  Weíll see when I get to the x - axis.  It will need a backing plate anyway,

Hi Gary, yes the basic catalogue shows the display and the scales as separate items with the two and three axis display both available.  But they also sell a package deal which includes which ever length scales you need at a reasonable discount compared with the separate items, less than the cost of the third scale.  Hence the economics of buying the three axis package and see what I can do.  It looks like some of the profiling and radius functions will work using the x - axis with one of the other two, so worth a try.  And the separate data memory function will definitely work with the third axis. I will get the other two going first.  If all else fails, I can just continue to use the stand alone quill scale that I already have, I can see that it is not simple to include, so I am forwarned.

I donít know if trepidatious is a word, but itís meaning is quite clear.  One of the interesting foibles of our language.  I donít know how it goes with google translate though.  I will definitely have a try at drilling some of the holes myself, but in locations where there is plenty of room to try again if it goes pear shaped.

I will try and post more progress this evening.

MJM460
« Last Edit: January 13, 2021, 08:47:42 AM by MJM460 »
The more I learn, the more I find that I still have to learn!

Offline MJM460

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Re: DRO Installation on a Mill/Drill
« Reply #5 on: January 13, 2021, 11:27:05 AM »
I decided to do the y -axis first.  I suspect it is more difficult in many ways than the x - axis, but it is a little more accessible.

The problem can be seen in the first two pictures.  First, looking at the table end on, you can see that the handwheel potentially intrudes into the space that is available for installation of the scale and reader.  Looking at the table and hand wheel side on, with the table at the end of its travel, you can see the extent of the problem.

My first thought was to make a mounting plate for the scale that had the outline of the handwheel cut out.  A bit of CAD work (cardboard aided design!) helped me find the centre of the wheel, but as you can see from the photo of my work, it takes a big bite out of the plate and I felt it might not be very easy to keep it straight.  After three tries, I realised that the handwheel was only a problem for the last 15 mm of table travel, 15 mm that so far I have not had the occasion to use, but in principal, not a good idea.  Then I realised that the handwheel is held in place with a simple set screw, and it was easily removed if I needed that 15 mm.  I could still operate the x travel from the other end.  If it becomes a problem, I can work on a shaft extension, so the wheel can stay in place.

With the handwheel removed I was much happier with the bracket shape and you can see the template fits quite nicely.  The remaining photos show machining the required shape.  The only wrinkle was chewing out a little extra to clear the gib strip adjustment screw.  I donít want to have to remove the whole scale and reader to adjust the gib strip.

Continuing the y - scale installation tomorrow.

Thanks for looking in,

MJM460

The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #6 on: January 13, 2021, 11:33:05 AM »

 ...they also sell a package deal which includes which ever length scales you need at a reasonable discount compared with the separate items, less than the cost of the third scale.  Hence the economics of buying the three axis package and see what I can do.  It looks like some of the profiling and radius functions will work using the x - axis with one of the other two, so worth a try.  And the separate data memory function will definitely work with the third axis. I will get the other two going first.  If all else fails, I can just continue to use the stand alone quill scale that I already have, I can see that it is not simple to include, so I am forwarned.

Yes, three for (more or less) the price of two makes sense.

I'll admit that I have only scratched the surface of my DRO so have not yet encountered any operations which require three-axis functions. If and when I do, that would be the time to bite the bullet and install a scale on the z. But even the few basic ways in which I have used the DRO have made its benefits really clear.

Yeah, these right-angle attachments for hand drills. I also have one. I hate using them - they're a nightmare to keep straight. But sometimes they will reach a spot that nothing else can get to! Give it a go, I say, and do not succumb to trepidationalism!

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #7 on: January 13, 2021, 11:43:11 AM »
MJM - I assume there was a reason why you couldn't install your y axis scale at the other side of the saddle?

That said, I installed mine at the opposite side from the handwheel but still had to mill down the end bracket to make space.

What we need are universal mounting brackets really  ;)

For what it's worth, I'll stick my youtube videos on my DRO install in your thread shortly. I have been justly criticised for the camera work (I'm working on it!), and I make no assumption that you will see anything of use in the approach I took, but at the very least it will do no harm.

'Cardboard Aided Design'. Love it!  :lolb:


Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #8 on: January 13, 2021, 11:49:37 AM »
t=575s

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #9 on: January 13, 2021, 11:50:27 AM »
t=767s

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #10 on: January 13, 2021, 11:55:14 AM »
Couldn't get the video embed function to work for some reason. I seem to recall there is a problem with this/fix for it. I just posted the links instead, for now.

Offline propforward

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Re: DRO Installation on a Mill/Drill
« Reply #11 on: January 13, 2021, 01:17:34 PM »
Neat work MJM - I like your approach.

Gary - there is a lot of vocabularization going on in this thread.  ;D
Stuart

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #12 on: January 13, 2021, 05:34:54 PM »
Clearly in that case we need to start a political party.

Of no particular leaning, though, this being a neutral forum.

Offline propforward

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Re: DRO Installation on a Mill/Drill
« Reply #13 on: January 13, 2021, 07:03:40 PM »
If thereís tea and biscuits involved, count me in.
Stuart

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #14 on: January 13, 2021, 07:13:02 PM »
Tea but no biscuits.

Cuts.

Sorry.

Offline propforward

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Re: DRO Installation on a Mill/Drill
« Reply #15 on: January 13, 2021, 07:14:58 PM »
Blast.

Well - back to our regularly scheduled DRO install.............(sorry for going off topic..........  :embarassed:   :popcorn: :popcorn: :popcorn: :popcorn:)
Stuart

Online Kim

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Re: DRO Installation on a Mill/Drill
« Reply #16 on: January 14, 2021, 05:35:22 AM »
Gary,
I fixed your previous posts so they link directly to the video now.

If you just paste the YouTube URL directly in the post it works.  Don't use the [ youtube][ /youtube] tags anymore.

Kim

Offline MJM460

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Re: DRO Installation on a Mill/Drill
« Reply #17 on: January 14, 2021, 07:53:11 AM »
Hi Gary, I donít know if there are any functions that use all three axis at the same time, though I think that separate data memory allows three coordinates per point.  Have to learn to use that later.  But there are functions that use x & z or y & z that might help profile edges of a baseplate or something.  So worth exploring, but in the end, x and y are the key ones, and the little separate scale on z certainly will do most of what I want.  But why pay for 90% of what is possible when the rest is perhaps within reach.

The other end of the table is basically identical to the end I selected for this scale, with a small advantage in cable runs, and it would also need the hand wheel removed for the last 15 mm.  More importantly, it has the y - axis lock screws, and I donít want to loose that function.

I saw your videos when you put them in Stewartís thread, thank you.  I think they are nicely done, so no criticism from here.  Your artistic talent shows through.  Thanks Kim for fixing the links.

Stewart, I think we had better get up a petition.  Biscuits and coffee should definitely be part of the platform with the tea.

Well, with all the excitement of getting those holes drilled by my very capable helper, I didnít take the number of photos I should have, though drilling and tapping holes to woodworking tolerances is hardly novel on this forum.

You might ask why I did not use a wider plate to accomodate the full handwheel cut out.  You can see the reason in the first photo below.  The machine base would interfere with the lower edge of the plate.  I first thought I just needed to lap join two plates.  It would have given the required clearance, but created a swarf trap between the back of the plate and the base casting.  A 6 mm thick strip separating the two should allow swarf to fall clear through.

You can also see in this photo the end view of the bracket I made for the reader.  It is basically the same idea as the supplied bracket, but the slots for mounting the reader are the right distance apart for the scale I purchased.  I also rearranged the location of the jacking screws which hold the vertical face properly vertical.  And to help line it all up, I added two small plates on the bottom of the bracket for jacking screws to help level the bracket.  One of these has been removed now it has fulfilled its function, and the tapped hole used to mount a cable clamp.

The final critical step is to check that the alignment of the scales is within the specified tolerance.  I checked with a dial gauge horizontal first, and used a couple of shims at the scale mounting bolts to make a minor correction.  Then with the dial gauge set up vertical I was able to check the vertical alignment over the full length of travel.  Slots at the scale mounting points allowed this vertical adjustment.  Perhaps I should have installed jacking screws under the scale, but it turned out not to be necessary.

With the first scale installed, I needed to install the display unit so I could power up and check that it works. 

The bracket for the reader was quite usable.  The supplied screws were only M4, but the slots in the bracket were generous, and would take M6.  I am sure that M4 would be strong enough, but in that category where it is too small for ease of installation, and all in, unnecessarily small.  I used M6 bolts that I had.  It uses easily replaced 5.0 mm drill for tapping, the taps are stronger, and there is plenty of room to have another go if I break a drill or tap, so I tried drilling and tapping the necessary holes myself.  I managed that without any problem, so now have a little experience under my belt for another time.

I mounted the display, and rearranged the cords I have for some lighting to accomodate the display, plugged it in and switched on.  It all lit up and displayed a reading for the y - axis as expected.  When I move the table, the display changes in increments of 5 micron as advertised.  Mind you, accuracy and repeatability may be different, but I am sure that I now know the table position more accurately than I did when I had only the scales on the handwheel collars.

  I call that success for the first step. 

MJM460

The first photo seems less than clear, so I have repeated it at the bottom at a higher resolution.
« Last Edit: January 14, 2021, 08:03:23 AM by MJM460 »
The more I learn, the more I find that I still have to learn!

Offline propforward

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Re: DRO Installation on a Mill/Drill
« Reply #18 on: January 14, 2021, 01:26:50 PM »
Nice install MJM - looks great. It's dealing with all the angles of the castings that's the biggest difficulty with these things. I like your solution a lot.
Stuart

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #19 on: January 14, 2021, 01:36:03 PM »

Stewart, I think we had better get up a petition.  Biscuits and coffee should definitely be part of the platform with the tea.


Please, not at a time like this! A backbench rebellion will split the party in two!

Very tidy installation so far, MJM. The plate you machined looks the business.

The y-axis locking screw - yes indeed! That would remove all doubt as to which side to install the scale on (if there had been any doubt in the first place)!

While my two videos are pretty much redundant here in your thread, thanks all the same to Kim for his intervention. However, I did try posting the links without using the button/tags when I was putting the videos up yesterday and it doesn't in fact work for me. I still can't see them - all I'm getting is a little bit of code: 't=575s' and something similar for the other video. Just for the sake of future attempts to embed videos - can you see them? I have a feeling this issue has been discussed on the forum before, but I can't remember where...

Offline propforward

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Re: DRO Installation on a Mill/Drill
« Reply #20 on: January 14, 2021, 02:16:16 PM »
The videos look good to me Gary - properly embedded now. Is it possible you have an adblocker or something? My various firefox guards sometimes play havoc with embedded pics and links on some forums.
Stuart

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #21 on: January 14, 2021, 03:02:08 PM »
Thanks Stewart.
Yes, it did occur to me it could be a browser setting. I use firefox too. Will have a look later.
gary

Online Kim

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Re: DRO Installation on a Mill/Drill
« Reply #22 on: January 15, 2021, 05:17:41 AM »
Gary,
if you're not seeing the videos when other people can, you might be using a secure link to MEM - if you see https:\\ at the front (or the little lock symbol) then you've used https and you need to re-enter the URL as http without the 's'.  For some reason, YouTube won't play from the secure version of the forum pages.

See if that fixes your problem.
Kim

Offline pieterb

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Re: DRO Installation on a Mill/Drill
« Reply #23 on: January 15, 2021, 06:17:36 AM »
Looks really nice, I installed a dro on my machines a few months ago.

After you made 2 parts on this machine you will be so mad at yourself for not doing this installation years ago.

You can check the accuracy with the longest gage block you have and a dial indicator. When I did this, I found that there was a difference of 0.01mm over 100mm. In the settings you can adjust this error, now it works perfect.

Anyway: well done and enjoy it.

Offline MJM460

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Re: DRO Installation on a Mill/Drill
« Reply #24 on: January 15, 2021, 10:10:19 AM »
Hi Pieterb, thank you for the nice comment.  I have realised for a while that this installation should be the next major tooling project, it just had to fit into time and budget.  I was even lined up to buy it when COVID hit, and I decided on caution until things became clearer.  I am quite happy with that first axis.  I have even had some use from it already, making the brackets for the x - axis, and it is fulfilling the expectations even at this early stage.  Unfortunately I donít have any gauge blocks, so that check will have to come later.

Now, for the x -axis.  I have already mentioned that I want to put the scales on the back of the table, as the front has the x travel end stops and also the x  - axis locking screws, and I donít want to loose those.

The first photo is a view of the location.  In principal, it is quite flat, and the scales could be mounted directly on the table and saddle.  However, that would require hand drilling holes in accurate locations , some of them with restricted axis due to the column.  Also, the table is only 40 mm in the vertical direction, while the scale plus its guard requires 50 mm for installation.  To finish off, I have to come up with a way of reinstating the swarf guard for the rear slides.  The space required by original heavy rubber strip as it folds up when the table moves towards the column will now be taken by the scale.  Provision to mount an alternative guard and avoid crashing into the relatively light weight scale guard into the column or guard.

In order to solve the issues, I decided to incorporate a backing plate to mount the scale on, so the required accurately located holes for the scale could be drilled using the machine, allowing much more tolerance on the backing mounting plate hole locations, and still allowing them to be drilled in locations where the column did not obstruct access.   Tho backing plate mounting holes are behind the scale.  Ideally I should have used low head screws with counterbore so for the heads, however I was able to obtain some counter sunk screws much more easily, and was able to countersink the holes in the plate enough to get the heads flush.  I donít believe countersunk screws are ideal for accurate locations, but with the final alignment adjustments made at the scale mounting screws, I am hoping it will be satisfactory.

I also decided to include a similar backing plate to mount the bracket for the reader, as this facilitated machine drilling the holes for the bracket mounting and the extra M8 tapped holes for the mounting studs for the swarf guard.

I bought some 50 mm wide aluminium bar for the two mounting plates.  Because the top one, screwed to the table will overlap the saddle by 10 mm and the two surfaces should be in one plane, I machined about 0.5 mm of the back face of the mounting plate 10 mm wide to make sure there was clearance.

Unfortunately, the mounting plate will cover the oil hole for the slide way.  I do not want to just cover that, knowing that I am unlikely to remove the whole scale to put a couple of drops in the hole.  I carefully marked the location of the hole on the scale mounting plate.  I drilled 2.0 mm from the edge of the plate down to the location of the hole and 4 mm in from the back face to meet it.  I opened up the hole in the top edge of the plate to 3.3 mm about 8 mm deep and tapped for a short grub screw.  Finally I removed the little fitting from the hole.  The hope is that I can put a few drops of oil in the hole, and that it will find its way down to the passage in the table.  I donít know if the plate will be flat enough to ensure the oil finds its way to where it is required.  Or perhaps I have to work out an arrangement with a little sealant between the plate and the table to help guide the oil.  Will see how much mess it makes when I try it.

The lower mounting plate for the reader required a little more machining to clear the slides, but nothing to difficult, as the mill is still useable for operations before the part is screwed in place.  I also tapped holed for the guard mounting studs.  When screwing the plates in place, I used business cards as shims to make sure there was clearance between parts where required.

Tomorrow the bracket for the reader and getting it installed.

Thanks for looking in,

MJM460
The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: DRO Installation on a Mill/Drill
« Reply #25 on: January 15, 2021, 06:11:23 PM »
Yes, you can't beat aluminium bar. Nice to work with, looks smart, and in this kind of application you can use it to relatively easily make the mounting surface that you want rather than struggle to work directly on the machine itself. Looks like a good setup for your scale. Good solution on the oil hole - will be interesting to see what you finally settle on to make sure the oil gets to where it should.

@ Kim - Yes, that was it. Interestingly, the videos were visible when I visited the page this morning and the little padlock icon had a red diagonal line through it. Seems to have sorted itself out with no help from me. I had actually remembered about removing the 's' from https but had tried taking it off the youtube URLs, not the MEM one - which of course didn't work! Thanks.