Installing a DRO on a PM-940 Milling Machine - Part 4 - 4-Axis EL400

This is part fourof installing an Electronica EL400 4-Axis DRO on my new Precision Mattnews PM-940M milling machine. Today we're finishing up the parts and installing the Z axis.
Tools used in this video:
*This site contains affiliate links for which I may be compensated
Dewalt Bifocal Safety Glasses (Amazon*): amzn.to/35eCYhl
Kurt DX6 6" Mill Vise (Amazon*): amzn.to/3nntHuh
Noga Deburring Set (Amazon*): amzn.to/2xMfiPz
YG-1 1/4" Alu-Power end mill (eBay*): ebay.to/2TRY4tM
YG-1 1/4" 120 degree spotting drill (eBay*): ebay.to/2MayWfj
Starrett 827A Edge Finder (Amazon*): amzn.to/38DGNPp
Drill America M4x.7 HSS Tap Set (Amazon*): amzn.to/2JMCqrq
Drill America M6x1 HSS Tap Set (Amazon*): amzn.to/392Dj7X
Allen Metric Metric Hex Key Set (*Amazon): amzn.to/2BVUYNw
General Tools Tap Wrench Set (Amazon*): amzn.to/2znrcOW
Baldor 332B 3/4HP Buffer (Amazon*): amzn.to/2GqOCMZ
Shars .0005" dial test indicator (Amazon*): amzn.to/3lo3Stq
NogaFlex Indicator Holder with Fine Adjust (Amazon*): amzn.to/33FwerY
Aventor 8" DPS IP54 Caliper (Amazon*): ebay.to/37y1Tg3
3Dconnexion SpaceMouse Compact 3D Mouse (Amazon*): amzn.to/2TSJ2q9
Focusrite Scarlett 2i2 Audio Interface (Amazon*): amzn.to/3jDamDD
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DRO Pros 4-axis Mill Kit: www.dropros.co...
Raw Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0 License
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[@Clough42]

I've had a couple of comments about the time I spent dialing in the scales with an indicator. It's not just about cosine error, as some have suggested. The manual has a tolerance specification: "Scale should be aligned with in [sic] 0.1mm/m from front side and top side. This alignment should be closer to zero for better results."

[@coreyobrien5932]

Though I'm a college student who has never touched a mill in my life, I always watch these videos the moment they come out. Great video and keep it up!

[@swe-fragels7722]

I did the same thing before I got any machines. When I bought my first lathe I had learned enought to have at least some Idea of how to run it the right way and to be able to achieve what I wanted.

[@Dieselfitter01]

Please do not stop. Everything from your insight, perspective and the comments generated are always a wealth of knowledge to keep inspiring everyone that follows.

[@azyfloof]

That a new Blondihacks t-shirt, or am I just now noticing it? Excellent work as always, James :)

[@stephenjohnson6841]

It's looking great James! Once again I wanted to thank you for great quality of your content.

[@KevinBox-xt4ei]

James I am enjoying your posts and in particular I like your attention to detail and accuracy. Well done

[@andrzej3511]

If I saw your DRO fully completed without knowing it was your creation, I would be convinced it was a factory optional equipment. :))) Excellent work, the diligence and accuracy of workmanship deserve special emphasis. You put in a lot of work but saved a lot of money. Most importantly: your own satisfaction as a bonus is PRICELESS! A masterpiece of precision mechanics - thought out down to the last detail.

[@newengineerontheblock]

Nice video as always! 8:45 Reminds me of a trick an old (read: wise) toolmaker taught me. Before running a tap drill, use a clearance drill (something like .030" larger than the nominal size) and drill down about .020-.040 shoulder depth. This results in a clean-looking hole with a small edge-break, and it prevents an uneven surface from top-thread-pullout when power tapping. Plus, you don't need to go thru later and de-burr the tops of all the holes. Great work, can't wait to see the quill functionality added to the DRO!

[@Clough42]

I know this is often used on parts to be hardened and ground to avoid leaving a feather edge on the thread that pulls up later.

[@UncleKennysPlace]

Fired up the electronics on my Clough42 ELS today ... nearly works. But not quite. I'll troubleshoot, which is half the fun. When I move I'm gonna upgrade on mill and lathe (have a tiny mill, a mini-lathe, and a combo mill/lathe, which is getting the ELS.)

[@bobuk5722]

Hi. This may help. I had a problem with the display. It was caused by the 5volt wall wart not putting out enough voltage. I replaced it with a better stabilised unit and it worked fine. BobUK

[@Clough42]

Cool. Many people have struggled, only to eventually discover a loose connection somewhere. It do be like that sometimes.

[@mkegadgets4380]

Thanks for sharing I look forward to the rest of the parts. I think when this is finished I could build my own, just by watching you build yours.

[@capt.kennethabney8789]

Great video, man what details. I watched the whole series from busting the crates to the last dro, felt like I was there. I’m shopping for a mill also and after watching this, I have decided I want a new one. These are very affordable, thanks James.

[@joewhitney4097]

Great work on the installation. I really enjoy your step by step process with the video and narrative. Thanks again.

[@DXT61]

You may have the cleanest shop i have seen.

[@vpcnc]

Nice work!

[@joell439]

Gettin’ there and having a blast doing it. Thanks for sharing.... 👍😎👍

[@PhilWhitten]

Hi James.....what a perfectly timed series of videos...I have just bought myself a mill similar to yours and will be setting up a 3 axis DRO very soon...as always great to watch your step by step with explanation videos. Keep up the good work...(Brisbane, Australia)

[@Theladorn]

I love this series and this channel in general. Always my first KZbin click come Saturday. Keep up the great content! Edit: I guess I should check the video description before asking questions. Thanks for being so thorough, James.

[@richardtww]

I have so enjoyed your videos I have been back to the start and watched all the ones I was interested in (and that was most of them) Helped me pass the time as I am shielding

[@jasonsirois3591]

I stumbled on your channel and love the content. I'm baffled there aren't 4x more subscribers. Keep it up man!

[@Clough42]

Tell all your friends!

[@jasonsirois3591]

@@Clough42 any way you could sneak in some coverage of your feeds and speeds in F360m ( or share your tool library) on the next project?

[@Clough42]

@@jasonsirois3591Next time I do a CNC project, I'll try to include that. Honestly, at this point, I'm still dialing in the high speed spindle.

[@jonshank9572]

Really enjoying the videos James. Great detail and talking through that detail with some insight into why you're doing it the way you are.

[@Ale_Lab]

Man I wait your videos the whole week. No doubt my favourite channel...Nice t-shirt BTW :-)

[@qivarebil2149]

@ 12.10 Nice wordplay - "no point in snapping a tap off"...LOL

[@gregloubser4744]

Nice one James. I must look at a DRO for my mini-mill.

[@MrPatdeeee]

Awesome James. But that is you kind Sir. Love it!

[@howesinc]

Good stuff, as always! Looking forward to some good working being done with this machine.

[@Dwarfracer88]

Good on 'ya reppin' the Blondie Hacks shirt.

[@bobuk5722]

Hi James, I like your use of worksheets - so much cheaper to make the mistakes on paper - or in the CAD. BobUK.

[@lucianobellebono9748]

Grande lavoro come sempre James. Ciao

[@rpavlik1]

Blondihacks shirt? I just came from there! Those oiling cups are so tiny and fiddly... Cool stuff. My brain always goes "won't it be a big deal to try to avoid cosine error on the scales?" Then I remember this is machining and so dialing in something with an indicator is pretty par for the course. 😄

[@Clough42]

I don't think it's just about cosine error, which would be negligible. The scale documentation has a tolerance spec. It says, "Scale should be aligned with in [sic] 0.1mm/m from front side and top side. This alignment should be closer to zero for better results."

[@rpavlik1]

That makes sense, I imagine the signal it's sensing isn't very strong or you'd be pulling chips up under the shield (for other scales, not z of course)

[@kevinwassellsr.5646]

That little guy sounds pretty nice for a hobby class machine

[@TheKnacklersWorkshop]

Nice work James...

[@ParsMaker]

nice work, enjoy the set-up

[@AmateurRedneckWorkshop]

Great install. Nothing says accurate like measuring with a DRO. Amateurs like me need all the help we can get.

[@brandontscheschlog]

Very interested to hear what you want to do with the quill lock. I was thinking of making improvements to my PM-932 quill lock as well. I thought aluminum or brass would be a better material for the lock.

[@Clough42]

I plan to use brass. The stock one is aluminum, but it doesn't have proper flats to bear on the quilll.

[@TomChame]

Nice job, thanks.

[@TheGOMES37]

Great video, as always. I understand you change the gear ratio on your mill head to help you tighten your draw bar by hand. However, would you not have more braking toque (which is applied to the tool holder) putting the milling head in a higher gear ratio? Putting it in a low ratio would increase the torque applied by the tool holder, which you are trying to brake with your hand, on the drawbar.

[@ericsandberg3167]

James, I was watching you work on this PM940 and I found it interesting that when you put the collet in the spindle, it looked like you held the nose of the spindle with your one hand and tightened the draw bar with your other hand.....does this 940 have a spindle brake or lock for the rotation of the spindle, or does it rely on the holding power of the gear train in the head to give rotational resistance so you can torque the collet.

[@Clough42]

There is no brake. I usually just shift it into low gear. There is no way I could hold the spindle nose by hand. I'm probably just holding the tool so nothing falls out until it's firmly in place. You can get a spline wrench to hold the top for tightening.

[@ronwilken5219]

Hi James, nice build and video. I have one observation to make. The machine's too short for your height. My back hurts everytime I see you address the table controls. Maybe a couple inches of riser either below the stand or between the stand and base would help. I realize it's a hobby machine and not an industrial setting but you may find it tiring in the long run. Keep well and keep the videos coming. RonW in Canada.

[@Clough42]

Yup. The wood for a 3.5" platform is sitting on the floor behind the mill, waiting for me to bolt it together.

[@thisnicklldo]

We need to tap M6, so of course we use a No. 20 drill. Hmm. A bit Franglais, maybe. No metric drills available at Le weekend, je guess.

[@ericcoffman820]

Always think outside the box..DRO's can work in a pinch as a cmm for measuring difficult features or dimensions that you don't have a proper measuring tool..Shop grade accuracy..

[@imajeenyus42]

Magnetic scales are so much easier to use than glass scales, mainly the totally separate read head!

[@m3chanist]

Nicely done, the 1950 rpm seems to be just fine for ally huh, I was concerned it would be too slow and gumming on my machine, so far it's not an issue, may not bother with a spindle speed upgrade, seems pointless.

[@melgross]

It is too slow. They have the same model with a 5,000 maximum speed. I’m surprised he didn’t go for that version. It’s not that much more, considering everything he buys. I hate the idea of using an 1/8” mill bit below 2,000. You really have to crawl.

[@drakonzebra]

Looking thick, James.

[@greybeard3759]

Does all the custom mount construction represent a typical installation or is this unique to your desires and your machine? Extremely tidy I must add!

[@Clough42]

The DRO came with a pile of standard brackets and hardware. X would have worked if I removed the way cover. Y would have worked except the angled surface for mounting the scale. Z would probably have worked, but would have been bulkier.

[@HolosSolar]

I know this was a long time ago, but did you have any idea about fixing the way the x axis scale covers the ball oiler ?

[@CORZER0]

Roger Roger. Do we have clearance Clarence? What's out vector Victor?

[@dough6393]

Good video sir thanks you. I am wondering if it would make more sense to have the Z axis display derived from the quill movement rather than the column? i will likely be putting a DRO on my mill soon.

[@Clough42]

I have a scale for the quill, too. The plan is to have the DRO sum them.

[@dough6393]

@@Clough42 Good day; that will be interesting to see in action, thank you for the reply.

[@hectorniebla4742]

James first enjoy your videos. Curious did you figure out how to combine the Z movement on the DRO?

[@Clough42]

It's just a setting. It's described in the manual, but I haven't done it yet.

[@arminth]

Blondihacks shirt! I had to subscribe now!

[@fasousa4798]

14:55 A M4 screw? That's sacrilege on Uncle Sam's turf... :o)

[@dougcox835]

I know this is the correct term but whenever I see DRO the first thing that comes to my mind is dielectric resonator oscillator.

[@horiap77]

I like your T-shirt :)

[@robertpowellj]

Dont you mean Z'ed axis?

[@frigzy3748]

just a random question: why not to use 3 jack screws instead of 4? One less screw to adjust and it should be sufficient to define a plane.

[@Clough42]

If the part is rigid enough, that would work. 4 allow you to twist it if it doesn't stay flat on its own.

[@concealed4carry]

I noticed you are not using any type of lock tight on the jacking screws. Is there any chance of vibration loosening them up?

[@Clough42]

Possible. Time will tell

[@bexpi7100]

Do you have any plans of adding a power drawbar similar to the NYC CNC power drawbar that uses an impact driver?

[@SGS_Engineering]

Great idea!

[@Clough42]

Possible. I haven't decided yet.

[@bexpi7100]

@@Clough42 if I understand correctly, using an impact driver the drawbar can be tightened without a spindle lock or putting it into a low gear, so that should bypass the need to fix the spindle lock. It also seems like the device isn't very complicated to make, though I could be wrong there.

[@SGS_Engineering]

@@bexpi7100 @Clough42 I have just made one! Check out my IG instagram.com/sgsengineering/

[@chevyfahrer]

very confusing for me as a german when you talk about C-Axis,and you are by far not the only one doing it.But i might get used to it.Nice shirt btw

[@rpavlik1]

Not C axis, Z axis. (Zee is what the Americans call Zed)

[@jimhunt5259]

I always say a miss is as good as a mile.

[@prototype3a]

How many thought he was going to hit the parallel around 3:40 ?

[@Clough42]

I did. It was close enough to leave thread-shaped cutting oil marks on it. But, as they say, clearance is clearance.

[@markhartings2255]

Be careful using leveling screws on cheap Chinese cast iron. With time and vibration, they’ll move on you. I found out the hard way.

[@melgross]

I usually put thread locker on them when I put them in. It takes hours for it to dry, so there’s plenty of time to adjust. I use a level 1 locker so I can break it loose just with just the hex wrench.

[@SunsetWingman]

Why do you drill 2 holes and then end mill between them? Why not just run the end mill between the 2 points?

[@jf713jf]

Probably wanted to use the holes as locators and to go full depth from one of them

[@Paul-pl4vy]

From England that’s zed

[@paul.newland]

James, how do you make your 3D view movements so smooth in F360?

[@Clough42]

3Dconnexion SpaceMouse Compact 3D Mouse: amzn.to/2TSJ2q9

[@paul.newland]

Wow, thanks for that - looks crazy so I’ve ordered one!

[@gretarsverrirsson9084]

👍👍

[@xenonram]

Your profile pic looks like Andy from Photonicinduction.

[@Clough42]

Fun fact: it's a photo that my sister took of me at my wedding in 2004.

[@Spoteddy]

Im very curious about your day job. I mean if this is your hobby? It seems very expensive hobby :D

[@bobweiram6321]

Why don't you manufacture these brackets as kits and sell them on eBay or Amazon as a kit? You might even get Precision Mathews or Grizzly to sell them as well.

[@pravado81]

Am I missing something here? Title says 4 Axis and the display shows 3 Axis.

[@matspatpc]

I've finally pulled the pin on getting a DRO - cheap Chinese one - don't want to pay more than half of the cost of my mill for a "better" one.

[@chevyfahrer]

get a LCD-Type.helps a lot with circle and grid drilling

[@matspatpc]

@@chevyfahrer Thanks, I went for a regularly LED version. They can still do circles and such, you just have to press a button for "next hole", and you don't get a nice graphical display.

[@chevyfahrer]

@@matspatpc yes,does the job also.i bought it because the regular was not available and i am glad now :)

[@matspatpc]

@@chevyfahrer I don't think it's a poor or bad choice. In my case, it was more or less the other way around - the ones available (within reasonable budget) were not LCD variants. I believe these systems are fairly interchangeable - standard pinout and functionality on the scales - so should I really find I need it, I can probably change over the head itself.

[@chevyfahrer]

@@matspatpc yes,the scales are the same,my dro actually was cheaper than the LED type.Prices changed between 85€ and 130€ for both styles displays just before christmas.For me as an absolut Mill-beginner it is just easier cause it kind of talks you through the steps by the graphic.

[@andersdoverud9046]

How do you do the tapping? It looks like you do the same as with the drill...

[@Clough42]

I use a spiral point tap, also called a gun tap, and just drive it through with the chuck. The trick is to apply light pressure on the quill and let it float so the tap pulls itself in and pushes itself back out when you reverse. I run it much slower than the drill so I have time to stop and reverse.

[@andersdoverud9046]

@@Clough42 Thanks, it looked like ridget taping, but I couldn't see. In sweden we call that a floating chuck.

[@rodneyavery3537]

Why not order the machine with the DRO from the factory?

[@Clough42]

It wasn't available, and they advised me that it wouldn't be available anytime soon.

[@rodneyavery3537]

@@Clough42 that's to bad. I've been looking at these machines not sure if I'll pull the trigger. I'm a retired machinist. My experience was mostly Automatic Screw Machines and CNC Lathes along with some CNC Mills. I processed and programmed all the work. Didn't have Cad used the P&P method. Lol

[@Clough42]

@@rodneyavery3537 A dovetail column mill like this has limitations vs a knee mill, like a Bridgeport. Specifically, the nod is not adjustable, and there will always be some challenges with so much weight on the Z dovetails. The benefit is that it it's smaller, and can (just barely) be handled with an engine hoist.

[@rodneyavery3537]

@@Clough42 I've been looking at the Knee Mill and a Gun Smithing Lathe from them. I don't do gun stuff but the long bar capability would be nice. I was looking at the mill you have because of ceiling clearance. I subd you so I'll keep watching to see how you like yours.

[@jonatanrullman]

Every time we get a full shot where your legs are visible I can't help but think of Monty Python when they sing dressed as waiters or something with aprons and then they turn around and have no pants on. And then I try to forget about it rather hurriedly.

[@Clough42]

I usually try to wear pants when operating machinery.

[@kimber1958]

Once again I say you should be on commission for selling these mills. Do you have help me make the decision Between a used Bridgeport Tide Mill or a brand new p.m. 9:40 AM /;~}

[@markloving11]

Is it just me or does the whole mill wobble side to side when drilling, tapping and cleaning the holes?

[@Clough42]

It's probably the camera moving.

[@markloving11]

@@Clough42 fair enough, great video as always

[@kennethnilsson6976]

Proper drill size for a M6 thread with pitch 1mm (coarse) should be 5mm. A drill no 20 is just over 4mm and too tight.

[@Clough42]

I used a #8 drill. Did I say #20 somewhere?

[@kennethnilsson6976]

@@Clough42 I saw someone mention that in a comment so I thought I would set things straight :-) but maybe I misunderstood.

[@Clough42]

Yeah...I saw that, too. #8 yields 73% thread depth vs 77% for 5mm. My tool supply house was out of 5mm cobalt drills.

[@twobob]

YAY \o/

[@twobob]

🤸‍♂️

[@bobearl7859]

Sure enough mounted it on the front then you wouldn't lose any of your x-axis

[@handdancin]

poor surface plate, it probably didn't expect to become a storage area when you hired it

[@rpavlik1]

But that's what horizontal surfaces are for 😉

[@ronwilken5219]

My dear departed wife, rest her soul, always maintained that horizontal surfaces needed to be covered or hold something. Read vase, candle stick, photo etc., Never could break her of the habit but I do understand the desire sometimes. If the work bench is full and the surface plate is open and you need to put some thing down then the SP is where it lands.

[@x8rsrule]

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