A few PM-833TV questions

[ycroosh]

Hi folks,
I finally decided to bite a bullet and get a new mill, and just placed and order for a PM-833TV.
Have a few questions:

1) I can't find the dimensions for the base footprint and mounting hole spacing. I'm going to weld a stand for it (didn't get the PM base, since I want to have drawers under the machine (shop space is very limited). I'd like to have the base ready by the time the machine comes, so I'd appreciate if someone could either point me to the official drawing, or measure the hole spacing and base width/depth.

2) Is the end of Z lead screw accessible from the top accessible from the top of the machine? I will be adding a power feed of some sorts to it, and ideally I'd want to use a servo motor driving the lead screw, rather than dealing with the bevel gears and have it stick out on the side (I have a stepper motor on my current SIEG SX4, and much prefer that arrangement than the standard PM way of dealing with Z power feed).

3) What DRO scales do you use on your PM-833? By the looks of it, it doesn't look like there is enough space on the Y axis for a glass scale, but PM has an option for a glass scale DRO. I'm curious how it's mounted. The other option are magnetic scales (they look like rebranded EMS/Electronica scales, and $1000 is actually not a bad price for that set). If someone has that option, could you please post some photos? If the installation looks reasonable, I might just order that and replace the EMS display with TouchDRO (for obvious reasons ). Also, what is the reference mark scheme on those scales? I.e. does the magnetic tape have standard EMS "mark every 50mm"?

4. Finally, what are the mods that people do to these machines? PM-833T looks to be very similar to the mil that Stefan Gotteswinter used to have, so I have some ideas for the mods, but curious to see what current owners ended up doing.

Also, as a bonus question: how well were the gibs fitted to the machine when you got it? I haven't owned any PM machines yet (both of my larger mills were Grizzly, and they needed a LOT of scraping on the gibs, so just trying to get my expectations calibrated for a PM mill).

Thank you in advance to any info
Regards
Yuriy

 

[AllenV]

The base foot print dimensions are on the PM web site for the 833-TV. Scroll down to "manuals and documents" . It is in there as "measured 833 hole pattern.

PM-833TV Ultra Precision Milling Machine – Precision Matthews Machinery Co.

www.precisionmatthews.com

Now... My recent experience building a base was that the outside dimensions were pretty good. The locations of the holes were off by 1/4 inch or so. I built the stand without holes, leaving what I thought was plenty of wiggle room for the holes. When the mill arrived I measured hole locations. My wiggle room was barely enough. But it worked. I'll measure my holes if you want, but who know how consistent they are machine to machine.

 

[AllenV]

Here is the DRO installed on my 833-TV. These are the PM glass scales, installed by PM

 

[parshal]

AllenV, that's what I have on mine and installed by PM, too. They work well.

 

[AllenV]

and the top of the column.

 

[ycroosh]

and the top of the column.

Thank you for the info. This is exactly what I was looking for.

 

[joeblow65]

I'm out and about right now but I also built my own base. I waited until it came in because the mount holes arent usually where the specs say they are. ill snap some pics of mine when I get home

 

[borges1]

Just built my own base for the same reasons. There is a picture of it here. Under the 3/16 steel top i put 6x2" C-Channel (or something similar they had at the steel yard) running side to side so that i had +/-5" to both hit the holes in the pm833 base and be able to adjust the machine front to back for where i decided to put it. I drilled the holes for the base after putting the machine on the stand and checking the location -worked great. If i had the space i would definitely have made the base 4' or even wider, two bays of drawers. Never enough storage in a shop.

 

[ycroosh]

So to close to loop on this:
I ended up cancelling the order for PM-833TV and went for PM-935TV. Over the weekend a local customer (bough my DRO a few years ago) let me play with his PM833 and while it's a VERY nicely made machine, it's actually a bit smaller and more "delicate" machine than my Grizzly G0720 (SIEG SX4). Mainly, though, the Z axis arrangement and low-speed motor torque were the two things that pushed me over.

PM-935 is a baby knee mill, and takes up a LOT more space, but I figured that I will be moving to a larger shop/garage in a few years, and it would make sense to "buy once - cry once". It is 2x more expensive, but seems to be more than 2x the machine.

I'll post some pics once the machine comes in (should ship early next week).

Thank you for your input, folks.

Regards
Yuriy