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Bought the Precession Matthews DRO, Now the fun really begins

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chiroone

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#1
Well, I bit the bullet and purchased the PM DRO for my 835s. At about $500, I could not resist price. It has glass scales and universal mounting brackets. I’ve never mounted one of these before, hopefully it won’t be too much of an ordeal. My understanding, I’m going to have to drill some holes in the cast-iron base and table of the 835 and then possibly have to construct some custom brackets. However, I hear it’s not so much of an ordeal that it’s not possible.

And pointers would be very appreciated
 

dfsmoto

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#2
I am interested to see your results. I would like to put one on mine too.
I have used my 835 almost everyday since I got it in the shop!
 

Balor

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#3
Add me to the list on seeing this done.

rngr1
 

chiroone

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#4
I’m planning on doing a photographic journal of the attempt. Hopefully, some others can learn from either my success or pitfalls
 

wvnitroman

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#6
Well, I bit the bullet and purchased the PM DRO for my 835s. At about $500, I could not resist price. It has glass scales and universal mounting brackets. I’ve never mounted one of these before, hopefully it won’t be too much of an ordeal. My understanding, I’m going to have to drill some holes in the cast-iron base and table of the 835 and then possibly have to construct some custom brackets. However, I hear it’s not so much of an ordeal that it’s not possible.

And pointers would be very appreciated
I don't want to hijack your post but I am seriously considering the PM 835S and was wondering what you think about this machine? Thanks, Kevin
 

chiroone

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#7
The PM835 is a solid machine, weighs in at like 1,400 pounds. More solid than a dovetail type machine and so far, although my use has been limted, it will chew through most everything.

It is an interesting machine, the top half is from Taiwan, the bottom from China. Everything is tight as can be and according to my dial indicator, it seems to hold .001 during the entire travel of the X axis.

Tell you this one thing, it was a real PITA getting off the pallet. If you get one, let me know, I will tell you how I got it off w/o killing myself very much
 

chiroone

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#8
BTW, ordered the DRO last week, will post the unboxing ceremony when it gets here.
 

Kiwi Canuck

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#9
I just started installing my DRO this weekend.

Drilling the cast iron table was pretty easy but hard on the nerves, but then tapping the holes raises the stress level a bit more.

I don't have a full set of letter drill bits yet so used my fractional set, not ideal when tapping metric threads but it worked for this application.

I did get the X Axis Installed yesterday and was hoping to get started on the Y Axis today but awoke to the news that we had a flood in one of the mechanical rooms, so no work on the machines today.

I watched a decent video on You Tube yesterday that helped a bit for the X Axis install, even though this video covers a magnetic scale the principle is the same.


Here's mine with the display installed and the X Axis live.



David
 

ddickey

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#10
How's that DRO install coming? I've got the X & Y done. Working on the Zed axis and there is quite a bit of taper on the base casting. Any ideas on mounting the base plate?
 

Kiwi Canuck

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#11
I have installed my scale, but I am waiting on a new batch of aluminum angle to complete the read head mount and don't have any pictures to post just yet.

I did a similar install to Tim Marks (explodee) install, but will install the bracket between the scale and the mill so that I can install a chip guard. (hope he doesn't mind reposting one of his pictures)

 
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ddickey

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#12
How did you compensate for the taper? What type of shim did you use?
 

Kiwi Canuck

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#13
I used the same brackets as shown in the photo above which have slots so they allow the scale to be installed in the vertical postion.

The angle brackets are flush against the column, (not shimmed) so slightly angled upwards but hardly noticeable and doesn't affect the install.

The scale is about 1 1/4" away from the column at the top and maybe 3/4" away at the bottom.

There are so many different ways to install the Z axis, but this was the easiest and neatest that I could find.

I started out copying this install but then realized if I wanted to use a chip guard I needed to move the read head bracket to the inside of the scale.

If it doesn't work I can easily revert back to the way I first installed it.

Use painters masking tape to do the layout and If you have double sided tape use it to mock-up the install before drilling.

Take your time and don't stress if the screw pack supplied is mostly useless, I have a good selection of stainless fasteners so just used those.

I even had to redrill a few of the scale mounting holes as the holes were different sizes

David
 
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ddickey

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#14
Angle brackets, okay I'll have to look for some of those.
 

Kiwi Canuck

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#15
The bracket kit that came with mine (which is the Easson Brand) are rather basic but I was able to use some of them.

I'll probably make my own once I get a new stock of aluminum as I can make them a bit nicer and they should fit better as well.

I'll certainly be making my own chip guards for the Z & X axis as the one supplied for the Z axis is not deep enough and the one on the X axis is deeper than needed and a bit flimsy so when I crank the table all the way to the back it's the first thing that hits.

David.
 

ddickey

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#16
I figured I wouldn't have to buy or make more brackets I thought mine was specific to my mill but I guess not. I still may just shim as I already have the hole drilled and tapped. The slope of the casting is ~ 16°.
 

umahunter

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#17
Is this the house brand I've been looking at one of those once back on my feet
 

ddickey

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#18
Yes it is.
 

Kiwi Canuck

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#19
I believe the bracket kit supplied with the DRO's from QMT (Matt) and the Aliexpress units are better than the Easson kit, based on the pictures of them online.

I don't mind making my own as it's kind of therapeutic for me to tinker on stuff like this and I can modify the ones supplied as well to get them to fit better.

I've seen a few installs on mills where the supplied brackets have been fine, on my lathe (PM 1340GT) I know I'll need make a custom bracket for the read head on the cross slide as the stock brackets will not be suitable.

Hey that's why we have these machines after all so we can make stuff.

David.
 

MarkM

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#20
Chiroone I have been following you for some time now. Still more toys to play with before you get to the nitty gritty and get some chips on that machine. Sorry but it s mill purchase time for me and patiently waiting for someone to review this machine. Good on you for getting the DRO. It really does do alot for a mill. Take the time to learn about all it can do. It will be well worth your time.
 

chiroone

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#21
Mark,
I should mention, that I recently moved, I also had four pods delivered to my house and filled my garage with their contents. Now there’s hardly any room to move much less use my 835. But I have to say, thus far it is a superb unit. You will not be sorry if you purchase the 835. All of the axes function to their full length with very smooth travel there is very minimal backlash and I was able to tram the mill to .001 for the entire length of the X ,Y and Z axis.

One thing I should mention, it has a funky process when you move from the high to the low gear. It’s not really a big deal, but you need to grab the spindle and turn it just a little bit to make sure that the clutch engages. Otherwise it makes a God awful clacking noise that is very disturbing to the ears and probably potentially damaging to the machine. I made that mistake a few times, but did not notice any damage to the machine.

I find I do have to stand on a stepstool though when tightening and loosening the drawbar. I’m about 5’8, I need to get on my tiptoes otherwise and, it makes for a little too much stretching without it.

The machine definitely has some have weight to it , much more so than even the heaviest dovetail type machine.

I have to say, it is fairly quiet and I can engage in normal conversation when the machine is running even at full speed.

when you buy the machine, I would definitely suggest getting the high precision vice, I got the 5 inch one. Also suggest getting the collet set And the Precision drill chuck. Do not even waste your time with the endmills that quality machine sells, they are pure Chinese junk and not worth even soiling the machine with them. Otherwise, everything that I got from Matt was excellent quality and I’m very pleased with it especially the vice
 

MarkM

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#22
Thanks Chiroone! Appreciate the feed back but I was kinda joking. Probably tired of seeing me post. No synchro gears so to be expected for engagement from low to high to low. The machine ticks all the boxes. Hopefully You get some more machine time! Thanks again!!!
 

kd4gij

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#23
Every BP type mill I have used. You have to rotate the chuck by hand while changing from hi to lo. Well you do get lucky once in a while
 

Kiwi Canuck

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#24
One thing I should mention, it has a funky process when you move from the high to the low gear. It’s not really a big deal, but you need to grab the spindle and turn it just a little bit to make sure that the clutch engages. Otherwise it makes a God awful clacking noise that is very disturbing to the ears and probably potentially damaging to the machine. I made that mistake a few times, but did not notice any damage to the machine.
The PM935TS has different procedure going from high to low versus going from low to high, the PM835S is the same.

http://www.precisionmatthews.com/wp-content/uploads/2017/02/PM-935-Series-Web-6-24-2017.pdf Page 10 describes the process.

BTW I read the manual cover to cover before I got my machine up and running but still did a few things wrong, I have since re-read the manual and now it's making a lot more sense, including wondering why I got that loud clacking when changing from low to high.

David.
 

chiroone

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#25
I did try that pushing on the pulley and belt procedure, but it did absolutely nothing. It was Matt that told me that turning the spindle will be a much easier And in my opinion a much safer procedure.procedure.
 

mksj

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#26
I think the connection to the back gear/high speed drive is typically a notched to notched engagement (like a spline but coarser) so most of the time the notches will not align to lock unless you turn the spindle after you have disengaged the back gear lever. There is also a back gear drive gear that moves the power through a smaller gear via a fork movement to the larger back gear. Not meshing the drive connections it can damage these teeth, so I always engage/disengage the back gear and turn the spindle by hand until the you here it snap apart/together and I feel the engagement. In back gear the spindle direction is reversed, some of the spindle direction switches (or separate switch) have a back gear setting which reverses the motor leads. On my mill with a digital (VFD driven) head, I use an electronic back gear sensor which will switch the FOR/REV VFD inputs, so the spindle rotation is always the same as the direction switch. I use momentary run stop switches for the VFD operation and also use sensors for auto reverse and auto stop/start based on the spindle location.

The DRO Pros also has a lof of posted pictures and information on DRO installs, a lot of great ideas. The X and Y tend to be a bit straight forward, the Z knee can be a bit more challenging and also adding chip covers. I ended up with a 4 axis magnetic scale setup which is a bit more forgiving as to setup then glass scales, but the glass scales work great once dialed in.

Back gear drive.jpg

Back gear proximity sensor activated.
Back Gear Sensor.jpg
 
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