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PM932 CNC Build

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ncf250sd

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Excellent! I will be envious of your extra Y travel!

I'm happy to share but you will have to confirm they will work for your mill. PM me your email and I will send what I have.

What type of motors will you be using? My Z is driven by a 42 size stepper with a 2005 ball screw and nut so parts were made accordingly.
I appreciate you sending the dimensions it will certainly help seeing a design that works and I will most definitely confirm dimensions on my machine. I'm pretty sure I will be using a 2005 screw and I am concidring a Nema 34 / 1700 oz-in servo but I am open to any suggestions. I will send you a PM.
 

jbolt

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I would recommend the the 2005 on the Z as a minimum. It could easily take a 2505.

I would check out this thread. http://www.cnczone.com/forums/benchtop-machines/122462-cnc-cad.html

He did a servo system. It is a long thread but worth the read.

I pull together what drawings I have and send along tonight. I also have most of my machine parts in 3D models. If you have a 3D CAD program that can open Parasolid files I can send those too.
 

ncf250sd

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I look forward to seeing your drawings, thank you. I read that thread, very jealous of the machine he ended up with.

I will put the largest liniear bearing I can without going excessive. Not yet fully decided on the axis motor but leaning toward the servo. It's all new to me, other then lots of reading, so please if anyone has recommendations let me know.
Are you happy with your z axis performance? I'm starting with the z conversion first as a learning experience and because if it doesn't perform well I will keep the machine manual and just use the z conversion as a power down feed.
 

jbolt

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The Z has worked very well. I'm still chasing a few thou of backlash but that is due to I went with 2 single ball nuts on each screw vs a double ball nut. It gives me more control over the preload but takes some time to get adjusted. The way my mill is placed it is not easy to get to so I have not done done any tweaking in a while. The 4200 oz-in stepper moves the head like it is not there. I have some plans in the future to correct the typical head nod on a dovetail column mill.

I went with a stepper system based on cost and ease of setup. I figure I can't turn a $2400 Chinese bench mill into a high end VMC so steppers were good enough.

What are you looking at for controls?
 

ncf250sd

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The Z has worked very well. I'm still chasing a few thou of backlash but that is due to I went with 2 single ball nuts on each screw vs a double ball nut. It gives me more control over the preload but takes some time to get adjusted. The way my mill is placed it is not easy to get to so I have not done done any tweaking in a while. The 4200 oz-in stepper moves the head like it is not there. I have some plans in the future to correct the typical head nod on a dovetail column mill.

I went with a stepper system based on cost and ease of setup. I figure I can't turn a $2400 Chinese bench mill into a high end VMC so steppers were good enough.

What are you looking at for controls?
The Z has worked very well. I'm still chasing a few thou of backlash but that is due to I went with 2 single ball nuts on each screw vs a double ball nut. It gives me more control over the preload but takes some time to get adjusted. The way my mill is placed it is not easy to get to so I have not done done any tweaking in a while. The 4200 oz-in stepper moves the head like it is not there. I have some plans in the future to correct the typical head nod on a dovetail column mill.

I went with a stepper system based on cost and ease of setup. I figure I can't turn a $2400 Chinese bench mill into a high end VMC so steppers were good enough.

What are you looking at for controls?
 

ncf250sd

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Jbolt,
I received the drawings, thank you. I haven't really decided on a controller, in fact I am reconsidering steppers or servo. I will do my research this weekend and hopefully have made up my mind.
 

jbolt

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Jbolt,
I received the drawings, thank you. I haven't really decided on a controller, in fact I am reconsidering steppers or servo. I will do my research this weekend and hopefully have made up my mind.
Yes there is lots to think about. For the stepper system with Mach3 I have been very pleased with the PMDX products. I use a PMDX-126 BB with a 107 spindle controller and an eithernet smooth stepper otion controller. Very robust combo tho Mach3 has a few quirks. I'm still waiting to see more feedback on Mach4 before I make the leap. If your a Linux person LinuxCNC is widely used and free. Mesa makes some really nice interface boards. We are using those on a servo based CNC router/mill I helped build for the high school. I'm not a Linux person so I don't run that machine.
 

Boswell

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I also am using the PMDX products with the Ethernet smoothstepper on stepper based machine. I loaded up Mach4 the other day but I was not happy with the user interface. I was surprised that I could not find hardly any user generated UI's given the focus on Mach4 (and Mach3) on supporting user developed interfaces. Anyway the result is that I am still very happy with Mach3 using the MachMotion screen set.
 

jbolt

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I also am using the PMDX products with the Ethernet smoothstepper on stepper based machine. I loaded up Mach4 the other day but I was not happy with the user interface. I was surprised that I could not find hardly any user generated UI's given the focus on Mach4 (and Mach3) on supporting user developed interfaces. Anyway the result is that I am still very happy with Mach3 using the MachMotion screen set.
Have you actually run Mach4? I'm curious if the M4 plugin for ESS is working? My only real issue with M3 is it does not always turn the spindle on. I should try reverting to a previous version, just need to do it.
 

Boswell

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I loaded Mach4 but I can't remember now if I actually loaded the Smoothstepper driver. I think so but I know I have not cut any parts using March4. I have never had any issues with the spindle not turning on using Mach3
 

jbolt

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I check in on the Mach forums from time to time at it seems like people have continued to have issues with the ESS plugin for M4.

Something is wonky with my version of M3. It worked fine for over a year and out of the blue started having the issue. I'm not the only one who has this problem and I'm told it is a bug in the software. I have a screen-set for my router that I really like I might try since is has it's own spindle macro.

From the Artsoft web site it looks like Mach4 hobby can only be on one PC at a time. If that is the case it's kind of a deal breaker since I have the mill and router plus I keep a copy on my CAD computer for testing g-code.

From your signature I see you have the DRO Pros magnetic DRO. How do you like it? I have one sitting in my shop waiting for my lathe to arrive.
 

Boswell

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The Dro Pro's magnetic DRO has changed my life as it pertains to the Lathe. I always struggled to make accurate parts or it took me so long to set things up and assure myself that I had it figured out correct that the "Hobby" turned into a "Job". With the DRO that all changed. I have never used another Lathe DRO so I can't really compare it to others but the installation video that they made was fantastic and I felt 110% confident in installing the DRO on my lathe and in fact the installation when without a hitch. I do wish I could figure out how to effectively store tool offsets so I did not have to "Zero" each tool but that has not been too big of a deal. I just make a light cut, Measure and input the actual into the control and it is "zero'd". I called them and they said that should upgrade to the new "Absolute" magnetic scales but I don't have any plans to do that anytime soon.
 

jbolt

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In a previous life when I worked as a machinist we didn't have digital readouts. Count turns, use indicators for critical work, know your backlash, mark the dials with grease pencils. About 15 years ago I got back into machining at the hobby level and the first thing I did was install a DRO. The one I had was The Shooting Star CBX which uses a rack & pinion w/encoder system. Made the machine a joy to use. I have used a few and setup a few machines for others with glass scales and they all have had some issues with the scales over time. I know a lot of people use them with great success but I'm leery. That's why I decided to go with the magnetic for the new lathe. I have never used pre-sets with tool holders. Is there a way to re-zero the tool library if you move the compound? I would assume so.
 

Boswell

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it is supposed to allow you to set a tool and then all other tools are relative to that one. This is pretty standard for tool presetting and on my Mill where the work piece can be in un-predictable places from job to job I think this make sense. But on a Lathe, the Center of rotation is exactly the same no mater what part I am making (X axis). I am sure I just need to spend more time with it but I am so happy with it that I have not taken the time to learn more about it.
 

taryngar

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Joined this forum just so I can pick your brain on converting my own PM-932 into a CNC machine. I'm ready to get started on it, so the first thing I'll need are the new screws. I'd like to find out your measurements to make my life a little bit easier. I think I'm going to go with double nuts to help eliminate any problems, unless I can be convinced that two single nuts is the better approach. One thing I wonder is, if you had to do it over again, would you move to a 2505 on the Z, or do you think the 2005 is good enough?

Thanks in advance. I'm sure I'll have a couple more questions once I have everything scattered across my garage. :)
 

dave2176

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I have the double nut screws. It is two separate nuts with a shim between them to tighten them up. One of the nuts doesn't have the mounting flange.
Dave
 

jbolt

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Joined this forum just so I can pick your brain on converting my own PM-932 into a CNC machine. I'm ready to get started on it, so the first thing I'll need are the new screws. I'd like to find out your measurements to make my life a little bit easier. I think I'm going to go with double nuts to help eliminate any problems, unless I can be convinced that two single nuts is the better approach. One thing I wonder is, if you had to do it over again, would you move to a 2505 on the Z, or do you think the 2005 is good enough?

Thanks in advance. I'm sure I'll have a couple more questions once I have everything scattered across my garage. :)
Welcome to the forums. You will find this a helpful and friendly place.

I would probably go with the double ball nuts vs. the two single nuts. We have been using them on the large CNC router/mill we built for the high school and they have worked well. Mine are due for adjustment which is a bit of a pain to do.

As for the Z the 2005 ball screw has worked fine with no issues. In the next couple of weeks I plan on updating my coolant enclosure so when that gets installed I will have a chance to inspect to see how it is performing. The full gear head is heavy. I have supported the lower end of the Z screw with a thrust bearing so I think the 2005 is fine. If I were to not support the bottom and just hang the screw I would go with the 2505 to have a larger shaft, nut & bearing up top.

Attached is the order form I sent to the supplier. The dimensions are based on my mill and how I chose to mount the motors. You will need to take your own measurements based on your mill and motor mounting system.
 

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taryngar

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Nice, thank you for that order form and info. Sounds like it's probably safe enough to stick with 2005 all around.

Any chance I could get your drawings for the new mounts and such? I understand that I would have to check my mill for match and adjust, but I'm sure it would still save a bunch of time. I like your design, so I'm probably going to copy a great deal of it. If it ain't broke and all that.
 

jbolt

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I have some drawings. I did make some in-progress tweaks to some of the parts but I'm not sure I updated those. I will have to see all of what I have.

I do have all the parts in Solidworks 2015 or in parasolid format if you have a 3D CAD program.

PM me your email and I will forward along what I have.
 

jbolt

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After two years of running with a pvc pipe and shower curtain enclosure I decided to update the enclosure to something a little easier to maintain.

The frame is 1x1 & 1x2 8020 extrusions. The back and sides are 1/16" aluminum and the doors are 1/8" polycarbonate. The door panels are 12" wide by 24" tall. The door hangers overlap so each side opens and closes together. The outer panels are fixed to the enclosure frame. The sides of the enclosure are two pieces with the rear piece being fixed. The forward panel can slide back for easier access for cleaning or for parts longer than the width of the enclosure.

Enclosure01.png Enclosure02.png Enclosure03.png Enclosure04.png Enclosure05.png Enclosure06.png Enclosure07.png
 

TomS

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After two years of running with a pvc pipe and shower curtain enclosure I decided to update the enclosure to something a little easier to maintain.

The frame is 1x1 & 1x2 8020 extrusions. The back and sides are 1/16" aluminum and the doors are 1/8" polycarbonate. The door panels are 12" wide by 24" tall. The door hangers overlap so each side opens and closes together. The outer panels are fixed to the enclosure frame. The sides of the enclosure are two pieces with the rear piece being fixed. The forward panel can slide back for easier access for cleaning or for parts longer than the width of the enclosure.

View attachment 138369 View attachment 138370 View attachment 138371 View attachment 138372 View attachment 138373 View attachment 138374 View attachment 138375
Nice!! Best thing I ever did was build an enclosure for my mill. Keeps the chips and coolant contained and easy to clean up. Are you going to plumb it for a wash down system? Makes cleanup much easier.

Tom S.
 

jbolt

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The shower curtains work great when they are new but after a while they get hard from the coolant and become difficult to deal with plus they only last about a year. I'm also planning on putting in some splash shields on the head for more splash control with the open top enclosure.

A revamp of the coolant pump system is in the works so I may think about adding a wash down system.

I'm also looking for a different coolant the the Rustlick 50/50. I really like it because it does not get rancid and does not affect my skin but if I'm not using the mill daily I still get rusting issues even with the higher concentrations. I'm hoping to find something that I can let sit for extended periods without having to pull my fixtures and wash the coolant off the machine.
 

TomS

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The shower curtains work great when they are new but after a while they get hard from the coolant and become difficult to deal with plus they only last about a year. I'm also planning on putting in some splash shields on the head for more splash control with the open top enclosure.

A revamp of the coolant pump system is in the works so I may think about adding a wash down system.

I'm also looking for a different coolant the the Rustlick 50/50. I really like it because it does not get rancid and does not affect my skin but if I'm not using the mill daily I still get rusting issues even with the higher concentrations. I'm hoping to find something that I can let sit for extended periods without having to pull my fixtures and wash the coolant off the machine.
I ran my mill for about 4 hours today and at the end of the run I had chips everywhere including stuck to the interior walls of the enclosure. Took me a total of 10 minutes to wash everything into the drain tray. I'll let it "drip dry" over night and vacuum the chips in the morning. I'm using a 50 psi Harbor Freight clear water pump on my system (about $50). It gives me plenty of pressure and volume. I plumbed in a recirc line so I don't deadhead the pump.

Interesting comment about Rustlick 50/50. I'm using it too and mixing it at 35/1. No rust problems at all. After washdown I don't wipe any surfaces, just leave the excess coolant where it lies. Sometimes it's a couple of weeks before I get back to the mill but no rust.

Tom S.
 

jbolt

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I'm mixing at 10:1 and I still find rust under the way cover and under fixtures if I leave it for more that a few weeks. Maybe it's my proximity to the SF bay.

Thanks for the heads up on the HF pump. I will check it out.
 

jbolt

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Tom. Did you document your coolant system? I don't see it in your build thread.
 

TomS

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I'm mixing at 10:1 and I still find rust under the way cover and under fixtures if I leave it for more that a few weeks. Maybe it's my proximity to the SF bay.

Thanks for the heads up on the HF pump. I will check it out.
It's been raining in Nor Cal for the last three weeks and I have no rust issues. My shop isn't heated either.

The HF pump part number is 62508. On sale for $47.97.

Tom S.
 
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