Bought the Precession Matthews DRO, Now the fun really begins

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
 
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!!!
 
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
 
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.
 
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.
 
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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