Capabilities: Is a 1 hp PM mill enough for 18-8 stainless steel? Or 2 hp?

[Gladiataar]

Hi Everyone!

I'm new to the forum and this is my first post. I'm in the market for a PM bench mill and it would be great to get some feedback from the experienced machinists out there. I've been primarily working with wood for the last 15 years, but find myself greatly limited (using existing equipment), when it comes to making a few basic metal parts. It's time to throw a truly dedicated metal fabricating machine into the mix.

I'm a HOBBYIST ONLY, needing to fit the machine in an already crowded (woodworking machines) two car garage, for small hobby projects. Typical usage/needs would be the following:

1) Parts/Month: 2 or 3 on average
2) Material Used: 80% aluminum, 20% stainless steel (all my parts have to be corrosion resistant)
3) Dimensions: 95% of parts fall within a 10 x 10 x 1 inch footprint
4) Operations: Edge milling (1/2” dia tool max), Face milling (0.080”/pass depth, 2” dia/pass width would be fine), Pocketing (1” deep in alum, 1/4” deep in SS), Drilling (thru 2” alum, 1/2” SS), Slot Grooving (0-90 deg in X&Y is a must).
5) Accuracy: +/- 0.005” (Stop laughing … I'm a woodworker!)

Side note: Icing on the cake, but don't necessarily need, boring and tapping.

I've done quite a bit of research now and keep coming back to the same conclusion. Everyone and their brother says don't mess around – get a knee mill. Although I can clearly see that pricing of a used Bridgeport is similar or less than a new Precision Matthews bench mill, I really don't think I need that big of a machine for what I want to do and where I want to put it. I don't have a lot of young male buddies around either, making me dread the thought of having to get (and stuff) a 1000+ lb machine into my garage and assemble it. Although I want to purchase a machine that allows me to grow a little bit, I definitely don't see myself cranking out the volume or complexity of parts that a knee mill is capable of. I have no intention of going CNC either. I'm in my 50's and prefer the old fashion manual methods of doing things. I also have no problem going slow in getting a job done, I just don't want to prematurely wear/degrade the machine or tooling due to pushing either of them beyond designed capabilities.

My gut feeling is that a nice Taiwanese made PM bench mill is the way to go. (If there were a quality, American-made machine in this size, I'd jump on it!) At first, I thought a PM-728VT would be a fine choice, but then realized that a PM-833TV significantly improves on it in almost every category for only $1k more. So that's where I've landed. Is this a good choice for my needs, especially given the occasional SS part and space/weight limitations? I figured I'd start out with the base model, plus Z power feed, bringing me to a grand total of $6k including tax and shipping. Again, from what I've been reading, this is where most simply scoff and point out that for this kind of money, I could easily get a nice used American made Bridgeport – which is absolutely true – but I don't want anything that BIG and HEAVY! Your words of wisdom in helping me choose a best fit PM mill (1Hp? 2Hp?) would be greatly appreciated.


Thank you!

 

[skcncx]

I hope you can land on your decision easier than the waffling I went through.

Same story, getting into metal working, hobby stuff. Went PM because of their support and customer service. I ordered the 1340GT lathe (not ready until June this year) and the 833TV... ready for pick up now. I have no experience to offer other than, from the specs, there are certainly key features/benefits of the 833TV over the 728VT that makes it a better option... as you have already noted.

Though, when you talk about the weight of a machine... seems like once you pass 500lbs it's not like you can just get a couple people to muscle them around.... I'd think moving a bridge port vs PM 833TV is similar'ish. Both need a crane, lift, pallet jacks... whatever. Though, for the benchtop mills, as I'm doing, making my own custom stand on levelling casters... so I the event I need to move it in the future, it's easily ready for it. And for space, I'll have a sizeable drawer system right in the stand/under the mill. Need to use all the space I've got efficiently.

It would seem a huge benefit on a Bridgeport style machine is the ability to adjust the nod... if my 833TV comes out of whack (as in, the "ultra precision" label is a bit exaggerated. I'm likely in for a lot more work than just dialing in the head/nod on a knee mill.

For us, the uninitiated, having little to know experience to know what we really need makes for tough decisions. Wisdom of the crowds says get the biggest best you can afford... certainly true, but I think of it as the right tool for my use/needs/expectations. Right sized is better, not just bigger, more features or expensive. I have expectations I haven't even discovered yet . Maybe my problem was, I really don't have a "these are the parts I need to make" scenario. All my uses cases and wants, expectations are speculative.

Part of what makes this tough, call PM, ask them, they are very helpful.... but they'll tell you both machines are very capable (728 and 833 Taiwan mills). The space, travel, z height, quill travel is what put me over the edge to go up to the 833... even though I preferred the manageability of the 728. Maybe the 728 will do everything you need.... just takes longer as the say.

If I speculate correctly on my 1340GT and 833TV purchases... I'll be happy... but only experience and usage will tell me, they're just right or, I could have gone smaller or oops, I really didn't know what I was/wasn't buying .

Sorry for the bloviating... I feel your dilemma, just went through it.

Welcome aboard, there are a lot of people on here to help you! My best resources so far has been the members on this site and PM's support.

 

[MrWhoopee]

When ordering an engine for my VW years ago, Bernie Bergmann was encouraging me to select a larger engine than I had in mind. He asked me "Did you ever look out the window of an airplane and say 'Gee, I wish this plane had a smaller engine'?"

You may regret getting the smaller motor, you will never regret getting the larger one.

 

[Chewy]

You might want to look at the Y capability. The 10" in X is a no brainier. There are a whole lot of machines that can't handle 10" in the Y without repositioning it and that could be a head ache. The depth of .080 on stainless may not be achievable without some serious HP. My PM30MV has 2 HP and I don't try for .080 in the Aluminum, let alone stainless. The extra weight will help dampen the vibrations, but the motor struggles.

 

[mmcmdl]

Once a BP or clone is on the cement in a garage , 2 people can move it without breaking a sweat . If space is an issue as you say , maybe the new smaller machines would be the choice . When it comes to $$$$ investing and work envelope , a used BP or clone will never lose money . The new machine as you say would most likely lose 40-50% the day you bought it .

 

[Larry$]

I traded for a used Jet knee mill quite a few years ago. Been happy with it. What I've found about limitations etc. : 3 hp I've never needed that much but don't really hog a lot. Far more time is spent optimizing setups and tooling changes than removing metal. Tooling and accessories will end up costing at least as much as the mill. Seems there is always something I'd like to have to make it easier. Any sort of variable speeding system is better than changing belt positions. Work envelope: I am far more likely to run out of Z-axis than anything else. Not in the size of the work but in the space used for work holding, boring head etc. A 3 axis DRO is so much easier to use than the dials. On a knee mill having a power feed on the knee has been worth it to me. I don't know about raising the head on a bench top.

Basic items you will want: decent vice, accurate drill chuck, caliper, micrometers just two to get started, boring head & bars, 115 pc. set of good drills, (I also really like my screw machine drills) a set of assorted HSS end mills, good edge finder, deburring tool, good files, set of HSS taps, a tap follower, set of parallels, chip & flux brushes, set of strap clamps, set of collets. Safety glasses always used! Way oil, cutting fluid/oil, gallon of WD-40 or =. Metal to machine. A metal lathe. A tooling cabinet. Note book. Charts for drill sizing, tapping, metric conversion. And you haven't even started down the rabbit hole.... Above all be safe, have fun.

 

[Gladiataar]

I hope you can land on your decision easier than the waffling I went through.

Same story, getting into metal working, hobby stuff. Went PM because of their support and customer service. I ordered the 1340GT lathe (not ready until June this year) and the 833TV... ready for pick up now. I have no experience to offer other than, from the specs, there are certainly key features/benefits of the 833TV over the 728VT that makes it a better option... as you have already noted.

Though, when you talk about the weight of a machine... seems like once you pass 500lbs it's not like you can just get a couple people to muscle them around.... I'd think moving a bridge port vs PM 833TV is similar'ish. Both need a crane, lift, pallet jacks... whatever. Though, for the benchtop mills, as I'm doing, making my own custom stand on levelling casters... so I the event I need to move it in the future, it's easily ready for it. And for space, I'll have a sizeable drawer system right in the stand/under the mill. Need to use all the space I've got efficiently.

It would seem a huge benefit on a Bridgeport style machine is the ability to adjust the nod... if my 833TV comes out of whack (as in, the "ultra precision" label is a bit exaggerated. I'm likely in for a lot more work than just dialing in the head/nod on a knee mill.

For us, the uninitiated, having little to know experience to know what we really need makes for tough decisions. Wisdom of the crowds says get the biggest best you can afford... certainly true, but I think of it as the right tool for my use/needs/expectations. Right sized is better, not just bigger, more features or expensive. I have expectations I haven't even discovered yet . Maybe my problem was, I really don't have a "these are the parts I need to make" scenario. All my uses cases and wants, expectations are speculative.

Part of what makes this tough, call PM, ask them, they are very helpful.... but they'll tell you both machines are very capable (728 and 833 Taiwan mills). The space, travel, z height, quill travel is what put me over the edge to go up to the 833... even though I preferred the manageability of the 728. Maybe the 728 will do everything you need.... just takes longer as the say.

If I speculate correctly on my 1340GT and 833TV purchases... I'll be happy... but only experience and usage will tell me, they're just right or, I could have gone smaller or oops, I really didn't know what I was/wasn't buying .

Sorry for the bloviating... I feel your dilemma, just went through it.

Welcome aboard, there are a lot of people on here to help you! My best resources so far has been the members on this site and PM's support.

You might want to look at the Y capability. The 10" in X is a no brainier. There are a whole lot of machines that can't handle 10" in the Y without repositioning it and that could be a head ache. The depth of .080 on stainless may not be achievable without some serious HP. My PM30MV has 2 HP and I don't try for .080 in the Aluminum, let alone stainless. The extra weight will help dampen the vibrations, but the motor struggles.

"My PM30MV has 2 HP and I don't try for .080 in the Aluminum, let alone stainless." Hmm ... this is very surprising and disturbing news. I was expecting to hear that an .080" pass in aluminum would be easy, and the only struggle would come from the stainless. If others chime in with similiar experiences when dealing with 18-8 or 304 SS on a 2hp bench mill, that would require some serious reconsideration on my part. Is this statement based on the use of a 2" diameter face cutter, or when making a single pass with a 1/2 diameter end mill?

 

[Gladiataar]

I hope you can land on your decision easier than the waffling I went through.

Same story, getting into metal working, hobby stuff. Went PM because of their support and customer service. I ordered the 1340GT lathe (not ready until June this year) and the 833TV... ready for pick up now. I have no experience to offer other than, from the specs, there are certainly key features/benefits of the 833TV over the 728VT that makes it a better option... as you have already noted.

Though, when you talk about the weight of a machine... seems like once you pass 500lbs it's not like you can just get a couple people to muscle them around.... I'd think moving a bridge port vs PM 833TV is similar'ish. Both need a crane, lift, pallet jacks... whatever. Though, for the benchtop mills, as I'm doing, making my own custom stand on levelling casters... so I the event I need to move it in the future, it's easily ready for it. And for space, I'll have a sizeable drawer system right in the stand/under the mill. Need to use all the space I've got efficiently.

It would seem a huge benefit on a Bridgeport style machine is the ability to adjust the nod... if my 833TV comes out of whack (as in, the "ultra precision" label is a bit exaggerated. I'm likely in for a lot more work than just dialing in the head/nod on a knee mill.

For us, the uninitiated, having little to know experience to know what we really need makes for tough decisions. Wisdom of the crowds says get the biggest best you can afford... certainly true, but I think of it as the right tool for my use/needs/expectations. Right sized is better, not just bigger, more features or expensive. I have expectations I haven't even discovered yet . Maybe my problem was, I really don't have a "these are the parts I need to make" scenario. All my uses cases and wants, expectations are speculative.

Part of what makes this tough, call PM, ask them, they are very helpful.... but they'll tell you both machines are very capable (728 and 833 Taiwan mills). The space, travel, z height, quill travel is what put me over the edge to go up to the 833... even though I preferred the manageability of the 728. Maybe the 728 will do everything you need.... just takes longer as the say.

If I speculate correctly on my 1340GT and 833TV purchases... I'll be happy... but only experience and usage will tell me, they're just right or, I could have gone smaller or oops, I really didn't know what I was/wasn't buying .

Sorry for the bloviating... I feel your dilemma, just went through it.

Welcome aboard, there are a lot of people on here to help you! My best resources so far has been the members on this site and PM's support.

You seem to fully understand the thought processes I've been going through. I liked your comment about the weight difference between the bench and knee styles being "similar'ish". I've watched a few videos of people installing both types, and as you say, a day-rental of an engine lift will certainty be on the agenda. However, the ability to store a whole toolbox under a mill is not a minor point when comparing what needs to fit in an already crowded garage like mine. Good point and definitely a check for the bench style.

Your point about the nod adjustment surprised me a bit. I did take note of the differences, but sort of assumed that was a one-time set-and-forget thing. Is the nod something that has to be adjusted frequently?

 

[Gladiataar]

Once a BP or clone is on the cement in a garage , 2 people can move it without breaking a sweat . If space is an issue as you say , maybe the new smaller machines would be the choice . When it comes to $$$$ investing and work envelope , a used BP or clone will never lose money . The new machine as you say would most likely lose 40-50% the day you bought it .

I hear you! I'd love to spend $1-2k less on a used BP, if it just wasn't so darn HUGE! I'm afraid my fellow woodworkers might get upset if a metalworking machine is the biggest one in the shop -- ha, ha! But in all seriousness, I was hoping that a smaller bench-sized mill could take off 2mm of 18-8 stainless in a single pass with a 1/2" end mill, but now I'm hearing possibly otherwise. Maybe I just misunderstood something here.

 

[Gladiataar]

When ordering an engine for my VW years ago, Bernie Bergmann was encouraging me to select a larger engine than I had in mind. He asked me "Did you ever look out the window of an airplane and say 'Gee, I wish this plane had a smaller engine'?"

You may regret getting the smaller motor, you will never regret getting the larger one.

I would agree, that's USUALLY the case, but have you ever noticed that ALL cars today HAVE to have 200+ hp engines in them, forcing them to remain at averaging 25-35mpg for over two decades now? Has it ever occured to car companies that perhaps some people out there would be happy to own a car that has only 150 hp, but gets 50mpg instead? The technology is there, but apparently everyone just wants the bigger engine even though more than half of them don't need it or will ever drive over 80mph.

This is fun ... I think I'm really gonna like this forum!

And you'll be happy to hear that after what I just learned about milling stainless steel, it's safe to say that the 1hp choice is off the table. Now I just have to confirm that a 2hp benchmill can even do the job at all.