PM-932M-PDF experience

[Ratz]

It was a long time coming, but finally I made a choice to purchase PM-932M-PDF Gear head milling machine end of last year.
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Time was mostly spent on acquiring tools and accessories to be able to do some work. Being a perfectionist installing Easson ES 12 DRO was quite a undertaking. Also found a nice LED powerful lamp.
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Not new to PM products as I purchased PM1236 lathe from Matt at <st1ersonname w:st="on">Quality Machine Tools</st1ersonname> around 2 years ago. Few modifications there as well. I will likely do a little post as well.
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Like with any Asian built machine a lot of time was spent taking things apart making sure they were clean and lubricated. If you would ask my opinion about the mill couple month ago I would likely give it a thumbs down. At one point I believed the purchase was a mistake. On the bright side most of the shortcomings were resolved and I am able to perform most of the work to my satisfaction. I would like to remind everyone that I am extremely fussy about my machinery and my tools.
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Lets not forget who the market is for this type of machinery. No production shop would even consider them. I on the other hand am grateful, as were there not machinery in this price range I would not own one at all. Especially in here <st1Western Canada where used worn out machinery goes fot top dollar. </st1
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Enough of the philosophy and to the point.
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I think PM-932M-PDF is a good piece of gear powerful enough for my type of work. Just the other day I was turning 4” face mill with 6 inserts on a steel block and was very happy with the result. Yesterday I was milling 1” aluminum with extra length end mill with precision that I was not able to accomplish when I first got the machine.
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Here is a partial list of shortcomings which I observed, got used to and or coirrected.
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Tilting the gear head is a pain and tramming it back to acceptable level is even worse. It would so much nicer to have a bolt in the casting to slowly and precisely move the gear head into alignment. (I am working on that one).
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What I know today, I would not attempt to run a mill without taking the feed box completely apart right down to pinion shaft as the feedbox didn’t feel very smooth in operation. I ended up removing the whole feedbox as the girt and sand I found in it made me feel sick. I left the pinion shaft in as the bearings were sealed and appeared good. There were some small springs and tiny parts to keep things interesting.
I made some improvements by fabricating shims of different size. After I cleaned, lubricated and assembled the feedbox I ended up with a very different machine. This was the turning point for me.
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This cleaning however; did not correct what I thought to be excessive backlash in manual feed handle. I found pocket milling just about impossible. The included quill DRO was indicating random numbers on different part of the scale (I found out since that few people experience that) it was a joke. Manual scale was another surprise one full turn is 0.110”. One can get used to that but the gearing was likely converted from metric to imperial and it has a 5% error (in my machine anyway). The good thing if you want to call it that is that the 5% error is constant and is negative, so you can mill some more material without spoiling your work.
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This part was easy. Quill DRO went to the rubbish bin and new 3” travel gauge with 3” diameter large face was installed. Finally I knew where the quill was.
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What followed was worse. The backlash in the manual feed turned out to be a backlash between the pinion shaft and the spindle. I believe in the end it turned out to be 0.070”. This can be found by moving feed operation handle outwards and lower the spindle little distance. Now without locking the spindle grab it with your hand and push it up. It weights 18 lbs. My mill went up 0.030 “ by hand but under load it reached 0.070”. This did not have any ill effect if surface milling as once the work was cleared, one could lower the spindle, lock it in place and carry on. Now in pocket milling of harder material the spindle was floating around within the backlash limits causing unpredictable results. Not good in machining.
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I know you will say, lock the spindle and move the gear head down, That is a proper way to do it. Well not exactly as new issues arise. Knee end mill anyone? Bring the work up to the spindle, would be nice. No chance we have a gear head mill.
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Using the power feed is unthinkable, as moves are uncontrolled and jumpy. Using the crank to lower the gear head is not precise enough for me. Jumpy moves are too large, gearing is just not right.
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Thinking about the knee end mill got me motivated that all I have to do is overcome the gravity and make the mill work on the other side of the backlash.
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Thinking about the poor gearing on gear head crank got me motivated to pursue another idea.
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So now I had to come up with two solutions. Improve the gearing for the gear head crank and/or modify spindle to work on the other side of the backlash.
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To overcome the gravity I dreamed up a new return spring. Let the pictures speak. The spring is 5/8OD with0.082 wire. The pulleys are small ball bearings with pressed on bronze with concave shape to accept diameter of the spring.
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To overcome the clumsy crank location with different gearing I used 1 to 2 chain sprockets and 40 chain. The sprockets ratio can be change in the future should I find the ratio unsatisfactory. The chain is then controlled by US made Andantex R3350 Anglgear with ¾” shaft. Since it takes 71 inch pounds to move the shaft I chose the R3350. The little gear is driven by 5/8” diameter W-1 drill rod (no particular reason just had it around the shop) Coupled by US made Lovejoy universal joint. Shaft is fixed in a bearing on the outer end and rotated by 9.5” hand wheel located beside present Y axis hand wheel. Let the picture speak again. This modification just happened so I can expand on it later.
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Should there be someone (eccentric and anal like me) interested in this project, I will be happy to provide more information and I still have couple of “U” joints left.
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As far as I am concerned, the spring modification was well worth it as without it I would likely got rid of the machine.
<ohew:>
Here is the link to my website for closer look at some interesting clean up process. http://www3.telus.net/oceanready/PM-932M-PDF.pdf

Cheers to all.


<o></o</o</o</o</o</o</o</o</o</o</o</o</o</o</o</o</o</o</o</o</o</o</o

 

[darkzero]

Nice work, very interesting mods. That's the first time I have ever seen a dial indicator used for the quill, the thought never even crossed my mind. I'm set with my quill DRO though.

 

[zmotorsports]

Nice work and upgrades but that is not exactly what I wanted to hear about the quality.

I too and very fussy and particular about my equipment, tools, shop, vehicles, home and everything else. The main two reasons I did not purchase older American machinery was, 1, I live in a machinery desert and the smaller home shop sized equipment simply doesn't exist and 2, I need the equipment to make parts and money. I didn't want to purchase a worn out piece of machinery and then spend several more thousand dollars and several months getting the equipment to my standards.

Thanks for the report but this is actually the first negative I have heard or read about pertaining to this machine or the 45M.

Again, not exactly what I wanted to hear.

Mike.

 

[Ray C]

Nice customizations....

A few things... The machine has an ACME screw to drive the head up/down and it's not recommended to do plunge Z-cuts by digging-in that way. The recommended procedure is to get the head close to the material and use the spindle to cut into the material. You're indeed correct, the machine wasn't designed for head plunge cutting. The PM 45 CNC can do this because it has ball screws in the column.

It is unfortunate that the factory doesn't do a good job of keeping things glean. Matt has tried for years to get them to address this but the outcome is hit-or-miss. The assembly lines do a reasonable job in the critical areas (inside the gearbox) but, I think they smooth-out the casting with grinding wheels after the unit is assembled and that exposes all the greased parts to grit. If Matt and crew cleaned each and every of the thousands of machines that are sold every year, the cost would go up a good 15-20%... Most folks ask for a 15% discount during the sales process so, it's unlikely such a price increase would be tolerated.

In any event, I'm glad the machine is functioning well for you and serving your purpose. That style of mill has been around for well over 20 years and it's passing the test of time. Matt has been selling them for over 10 years (and more than half go to machine shops) averaging several hundred machines per year and has never had a serious problem with one that couldn't be resolved.

Ray

 

[chuckorlando]

That spring mod is pretty slick.

It is possible you got one that fell through the cracks. I have no experience but it seems most are pretty happy with them.

 

[Ratz]

Nice work and upgrades but that is not exactly what I wanted to hear about the quality.

I too and very fussy and particular about my equipment, tools, shop, vehicles, home and everything else. The main two reasons I did not purchase older American machinery was, 1, I live in a machinery desert and the smaller home shop sized equipment simply doesn't exist and 2, I need the equipment to make parts and money. I didn't want to purchase a worn out piece of machinery and then spend several more thousand dollars and several months getting the equipment to my standards.

Thanks for the report but this is actually the first negative I have heard or read about pertaining to this machine or the 45M.

Again, not exactly what I wanted to hear.

Mike.

I was/am in the same kind of situation. I did not want to purchase worn out machine for my small shop. I know the bulky machines are more stable but I simply have no room. My friend purchased old machine and spent considerable amount of time rebuilding it, which is nice if you want a project for retirement. Like you, I have no time, as I run my own business and I use the machine to make parts.</SPAN>

One of the reasons I purchased the machine was on spec and two days on the internet. I do not have the links anymore , but I remember someone said the manual feed handle (the dial wheel in the front was practically useless. I found thee posts about the quill DRO with randomly jumped around. (for me they were also too small to watch as you have to keep an eye on the work). I dismissed all this. and went ahead.</SPAN>

Having said that I am now enjoying the mill and am familiar with the inner workings which enables me to better judgment of what the mill is capable. I expect a machine (and the operator) to make a part to 0.0005” tolerance and I have no issues to achieve that. It is unfortunate it took so long to get there.</SPAN>

I did not feel good about all the shortcomings in the beginning, and wished someone had gone through this before. Instead I had to dream up all the fixes.</SPAN>

That is the main reason I wrote about my experience. Maybe my mill was a reject and it is a isolated case. I do not know. I just hope it helps someone like me.</SPAN>

The good news is that there is a light at the end of the tunnel and I would not give up my mill at this time.


Sorry if I made you feel bad, however do not think there is a better machine for the money. They are all the same.

Radek

 

[Ray C]

I was/am in the same kind of situation. I did not want to purchase worn out machine for my small shop. I know the bulky machines are more stable but I simply have no room. My friend purchased old machine and spent considerable amount of time rebuilding it, which is nice if you want a project for retirement. Like you, I have no time, as I run my own business and I use the machine to make parts.

One of the reasons I purchased the machine was on spec and two days on the internet. I do not have the links anymore , but I remember someone said the manual feed handle (the dial wheel in the front was practically useless. I found thee posts about the quill DRO with randomly jumped around. (for me they were also too small to watch as you have to keep an eye on the work). I dismissed all this. and went ahead.

Having said that I am now enjoying the mill and am familiar with the inner workings which enables me to better judgment of what the mill is capable. I expect a machine (and the operator) to make a part to 0.0005” tolerance and I have no issues to achieve that. It is unfortunate it took so long to get there.

I did not feel good about all the shortcomings in the beginning, and wished someone had gone through this before. Instead I had to dream up all the fixes.

That is the main reason I wrote about my experience. Maybe my mill was a reject and it is a isolated case. I do not know. I just hope it helps someone like me.

The good news is that there is a light at the end of the tunnel and I would not give up my mill at this time.


Sorry if I made you feel bad, however do not think there is a better machine for the money. They are all the same.

Radek

I too feel badly when a machine comes gunked-up. It should not be that way. But in any event, all the machines are not the same. The PM units come with hardened internal gears which is an extra option at the factory. Also, the motors are outfitted differently with a much higher efficiency unit. We used to sell the standard motor (on the earliest models of the PM 45) but, found a much better motor in the 80% efficiency range instead of the low 70% range. The old motors got pretty hot whereas these take hours of use and are only warm to the touch.

As for all the other mods you've done... that's a personal choice -entirely up to you. There are tens of thousands of those machines in past production and if the basic design were unacceptable they would have gone the way of dinosaurs...

Unfortunately, yes, yours ended-up with grit in the PDF side gears but as mentioned, if each machine were checked to that level, the base price would be far out of line with what people expect to spend. In days gone by, equipment was sold with a service contract whereby those things could be addressed. Such a service contract now, would exceed the cost of the machine. When buying a $75,000 Morie, Mazak or Hass, the situation improves -but I also know plenty of people who've had their fair share of issues with the high end stuff...

The good news here, is that you're machine is working the way you want it to and you've essentially done "After market mods" much the same way folks will buy a Mustang or Corvette and before they drive it around the block, send it off to a custom shop... It's a free world to do those things and all the aforementioned are good platforms to take as a starting point.

Ray

 

[Ratz]

I too feel badly when a machine comes gunked-up. It should not be that way. But in any event, all the machines are not the same. The PM units come with hardened internal gears which is an extra option at the factory. Also, the motors are outfitted differently with a much higher efficiency unit. We used to sell the standard motor (on the earliest models of the PM 45) but, found a much better motor in the 80% efficiency range instead of the low 70% range. The old motors got pretty hot whereas these take hours of use and are only warm to the touch.

“All the machines are not the same”. You are correct, there are some differences. The motor with aluminum heat sink and cooling fan on top is a nice motor. Hardened gears, certainly.
<o</o
Maybe a clarification of my expression - all the machines are the same - deserves to be expanded on. “All the same” is in reference to very high percentage of Chinese products. This phrase evolved from experience of purchasing a lot of Chinese equipment and tooling. Every piece I acquire, I end up stripping down and reassembling with TLC. They are “not the same” as in variation of process making them acceptable to one’s standard. Some need just oiling, some need to shake the sand out, some need to be machined to get rid of the rust. Some even end up in rubbish bin. Yes, they are not the same there is a variation in type of repair. Yes, they are all same, as they all seem to need something.

As for all the other mods you've done... that's a personal choice -entirely up to you. There are tens of thousands of those machines in past production and if the basic design were unacceptable they would have gone the way of dinosaurs...

Nowhere did I blame the machine, I simply outlined the experience of shortcomings based on my experience and my requirements. Yes, my mods are a personal choice. However they are out of necessity to manufacture parts with reasonable accuracy. I am simply passing on information to help someone who may have similar needs as myself. I know I would have appreciated any help at the time when I was scratching my head for ideas.

Unfortunately, yes, yours ended-up with grit in the PDF side gears but as mentioned, if each machine were checked to that level, the base price would be far out of line with what people expect to spend. In days gone by, equipment was sold with a service contract whereby those things could be addressed. Such a service contract now, would exceed the cost of the machine. When buying a $75,000 Morie, Mazak or Hass, the situation improves -but I also know plenty of people who've had their fair share of issues with the high end stuff...

Unfortunately yes, my PM-932 ended up with the grit. Statement of “If machine were checked to that level the price would be out of line” rings the bell with my statement in the original article. Starting with “Lets not forget who the market is for this type of machinery”. You only get what you pay for, the sand is free.
<o</o
I also indicated that it is a partial list of observed shortcomings. So let me expand.

The feedbox mating surface was machined 0.030” under putting a pressure on the worm gear in power down feed of the quill. Someone’s solution was to cut piece of aluminum from an old scale and shim the feed box away from the gear head to avoid binding.

This quick fix caused other issues of misalignment like worm shaft to manual feed where I thought the problem was in the fist place. Misalignment of all the <o</oconnecting parts between feed operation handle and pinion shaft.<o</o
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I measured required dimension and fabricated a shim all around the feedbox which took care of the misalignment.

Is this how a precision machinery is assembled? I do not think so. Let the attached picture speak for itself.
<o</o<o



The good news here, is that you're machine is working the way you want it to and you've essentially done "After market mods" much the same way folks will buy a Mustang or Corvette and before they drive it around the block, send it off to a custom shop... It's a free world to do those things and all the aforementioned are good platforms to take as a starting point.

Ray

I did get a bit of chuckle over your aftermarket modifications statement. I think the owners of the Corvette or Mustang would take their new cars back to the dealership to get them running in the first place before any aftermarket modifications.

Cheers to all

Radek</o</o

 

[Ray C]

We would probably love it if more folks here were talking about Mori's, Haas and Mazak -I sure would love to know more about them -and even the problems they have...

But nonetheless, in lieu of the replacement machine that was offered (with return shipping) the replacement side-box assembly should be in our hands by now. It was express shipped from the factory and Matt indicates the tracking number shows delivery at/around today -or sometime extremely soon.

When people have legitimate warranty issues, things get taken care of rather quickly (unlike my last experience with a new car purchased from a new car dealer).


Ray

I did get a bit of chuckle over your aftermarket modifications statement. I think the owners of the Corvette or Mustang would take their new cars back to the dealership to get them running in the first place before any aftermarket modifications.
<o</o
Thank you for expressing your kind pleasure that my mill is operating to my satisfaction.

Cheers to all

Radek

 

[Ratz]

We would probably love it if more folks here were talking about Mori's, Haas and Mazak -I sure would love to know more about them -and even the problems they have...

If someone has a problem with one of the top end machines you are speaking of he/she is in the wrong trade.<o</o


But nonetheless, in lieu of the replacement machine that was offered (with return shipping) the replacement side-box assembly should be in our hands by now. It was express shipped from the factory and Matt indicates the tracking number shows delivery at/around today -or sometime extremely soon.

When people have legitimate warranty issues, things get taken care of rather quickly (unlike my last experience with a new car purchased from a new car dealer).


Ray

Now after your comment of replacement machine, I realize, that I am discussing an issue with Precision Matthews Sales/Support.<o</o
<o</o
Let me make something clear. I like Matt of Quality Machine Tools, being in business myself I am fully aware what is he dealing with. Matt was courteous, generous and anything he does is done with integrity.<o</o
<o</o
Quality Machine Tools was contacted on February 2[SUP]nd[/SUP] with some of the issues discussed in my posting. Matt did acknowledge and took full responsibility of the difficulty. Various options were discussed and one of them was an upgrade to a more expensive mill. I repeat “upgrade to a more expensive mill” including free shipping.<o</o
<o</o
Now, please remember as I have stated, I live in <st1:country-region w:st="on">Canada</st1:country-region> which complicates the matter. I had to pay brokerage fees and taxes when I imported the mill. Be aware that I paid all shipping costs within the <st1:country-region w:st="on"><st1US</st1</st1:country-region> to my forwarding agent on the west coast. Also, returning the original mill to get an upgraded mill would have been at my cost.
<o</o
At no time was a replacement machine ever discussed as I had one PM-932M and at the time did not think much of this machine. Matt did offer to replace the feed box to see if it will fix the issue. Matt also offered to replace the spindle DRO.
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When I asked for complete gear head under warranty there was not much response.<o</o
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