Precision Matthews PM-728VT CNC conversion

Koenbro,
Awesome drive setup for the encoder:) Made me chuckle. Nothing like coming up with a temporary solution using what you have. Great way to test components and wiring. Its also 1 to 1.

I never thought a router could be used on aluminum. What a great way to make brackets.
 
How can I use a tool probe on the PM-728? I mean if I put it into an R-8 collet, then swap it out for the mill, the x-y and height info are lost. Is it possible to adapt one holder per tool using BT40 or similar?
 
jlchapman said:
Koenbro,
Awesome drive setup for the encoder:) Made me chuckle. Nothing like coming up with a temporary solution using what you have. Great way to test components and wiring. Its also 1 to 1.

I never thought a router could be used on aluminum. What a great way to make brackets.
Click to expand...
Thank you -- others seem to disapprove of the the axial attachment for the encoder, but to me it seems logical and simple. And yes, a router is an awesome way to cut sheet aluminum. I do it all the time with 1/16" and 1/8" 6061; and have even cut 1/2 plate once, with shallow passes. I prefer a 1/8" one-flute Onsrud carbide mill from McMaster, run at 24,000 RPM and 75 ipm. Very clean edges.
 
koenbro said:
How can I use a tool probe on the PM-728? I mean if I put it into an R-8 collet, then swap it out for the mill, the x-y and height info are lost. Is it possible to adapt one holder per tool using BT40 or similar?
Click to expand...
Koenbro,

Take a look at the Tormach Tooling System (TTS). It uses a 3/4" master collet and exchangeable tool holders for repeatable Z height and quick clamping.

TTS - Mill Toolholding - Toolholding - Tooling

tormach.com tormach.com

I have had good success with them. The system is appropriate for spindles up to 10k rpm and not more than 3HP.

For tool holders, there are a wide variety of styles available but you will mostly use set screw holders for weldon shank endmills and ER collet chucks for drills and carbide endmills without weldon shanks.

I have a mix of Tormach genuine and import chucks. They run about $17 per genuine Tormach set screw holder or import collet chuck and $35 for a genuine Tormach collet chuck.

They do add cost to your tooling but are really the best for CNC. Pair it with a pneumatic drawbar and you can change tools in about 1 second with height repeatability to a tenth or so.

I started with 5 ER20 collect chucks (good up to 1/2" tools) maybe 6 years ago and now have almost 30 different holders, drill chuck, boring heads, slitting saws, and electronic edge finders.

Tormach sells a small granite surface plate (6x9") with a hole in the corner to preset your tools off the machine using a height gage. I have this as well and find it to be an excellent method.

I do not own a probe, but I have a 3D edge finder (one of the electronic ones with a ball tip) and use that as my master. Once a part is zeroed with that, all my tool lengths will be spot on.

The import chucks are good quality (once you reject any obviously bad ones) but I strongly suggest paying the extra bit for Teknics ER collets. Import collets are just no good for runout.

I show these a few times in the build log for my mill. Here is one post regarding them and the pneumatic drawbar.

www.hobby-machinist.com

G0704 CNC AC Servo Rebuild (Picture Heavy)

The machine is now as good or even better then when I started this upgrade. I am going to hold off on actual machining for a little bit, but if I need to use it, it is ready to go!
www.hobby-machinist.com www.hobby-machinist.com

-Mike
 
Last edited:
macardoso, I'm also converting a PM728(should be here this week) to cnc. I bought the Lyndex TTS collet adapter, bunch of ER20 collet chucks, superfly, drill chucks, granite plate and engraver from Tormach. Tormach has received alot of money from me. But one thing with machining is your going to spend alot on tooling. That part never stops.

I'm also a firm believer in the Teknics ER collets, I use those in my big mill. Pneumatic drawbar is definitely on my radar and will happen at some point.

I've bought some end mills. Mostly YG1 alu-power 3-flute 45 degree, 1/8", 1/4", and 1/2". I've bought all square end. What have you found you need for ball end mills? What size end mills do you mostly use? Any other end mills you recommend?

I skimmed through your build. Nice build. Enclosure is great. I would expect nothing less from somebody that works with Allen Bradley equipment. I have one of there Micro800 series PLC's in my extra parts.

Jerry
 
Check the runout on your Lyndex R8 Collet. I have 2 R8 collets for my TTS tools. One is Lyndex labeled and one is Tormach labeled, both of which I bought from Tormach. The Lyndex has so much runout it is basically unusable, whereas the Tormach is excellent, as good as my Hardindge collets.
 
Thanks Paul. I'll check that. I bought my Lyndex from Tormach.
 
jlchapman said:
macardoso, I'm also converting a PM728(should be here this week) to cnc. I bought the Lyndex TTS collet adapter, bunch of ER20 collet chucks, superfly, drill chucks, granite plate and engraver from Tormach. Tormach has received alot of money from me. But one thing with machining is your going to spend alot on tooling. That part never stops.

I'm also a firm believer in the Teknics ER collets, I use those in my big mill. Pneumatic drawbar is definitely on my radar and will happen at some point.

I've bought some end mills. Mostly YG1 alu-power 3-flute 45 degree, 1/8", 1/4", and 1/2". I've bought all square end. What have you found you need for ball end mills? What size end mills do you mostly use? Any other end mills you recommend?

I skimmed through your build. Nice build. Enclosure is great. I would expect nothing less from somebody that works with Allen Bradley equipment. I have one of there Micro800 series PLC's in my extra parts.

Jerry
Click to expand...

I've found the Tormach tooling to be quite nice. The Chinese knockoffs are hit and miss, but I've always had a good outcome of receiving the correct number of chucks in specification, even if I have to argue with the seller to make it right.

I've only ever used the Tormach branded TTS collet and it has been as good as the somewhat crappy spindle of my mill. The pneumatic drawbar was a bit of work to build but has performed perfectly with no adjustments since.

I have a G0704 and after LOTS of testing, I feel the mill is properly sized to utilize 3/8" cutters in aluminum and 1/4" cutters in steel. Nothing is stopping you from loading up a 3/4" endmill but you will suffer with the rigidity problems that come from the larger diameter. I rarely use a ball endmill for my work. I keep one 1/4" ball endmill in the tool rack. With ball endmills, you trade off with surface finish (larger is better) for feature definition (smaller is better).

I love the YG-1 ALU Power endmill. My main tool for aluminum is a 3/8" standard length cutter and I've gotten about 4 years of lifespan out of it. If you can use a roughing tool and then come back with a finisher, the serrated roughing endmills are great for reducing HP and side load on tools which helps these smaller machines.

Thanks for the compliments :) AB makes nice stuff.
 
I hate wedge anchors.

Not removable and you lift the machine to move it.

Drop in type works well.

Our shop was built with what looks like lag bolts for concrete, real easy, drill hole, blow out dust and insert screw.

Rated stronger than the wedge too.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
You can epoxy threaded sleeves into the floor. There are also female threaded anchor out there; I used some on my garage door hurricane braces.

Sent from my SM-G892A using Tapatalk
 
You must log in or register to reply here.
Back
Top