Making Molds On a POS Manual Mini Mill

It cuts quite accurately . The clamp system puts no vertical force on the spindle . I have more problems with the spindle "climbing" if I try a cut without locking it . I have watched the Z readout on the DRO as I tighten the clamp and it doesn't move at all .
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The RF-45's power and working envelope are significantly better than my mill, which I consider big enough.
Reply to
Jim Wilkins
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That was one of the big deciding factors for me with the PM1440ELB. A large thru spindle bore. At thee time it was marginally cheaper than the simialr size Grizzly, and had a through spindle bore.
Same with the
These is an denigrating seeming attitude I see sometimes in machining groups. "I don't NEED that," or "I never needed that." Sometimes its just an observation, but most times it seems like either a little bit sour grapes or a put down of somebody who, "Does need that."
Story time. One time I showed a picture of a screw up I made with a round over bit. Worse it was a $100 carbide round over bit. I thought it was amusing. Nothing more. A couple of the manual machinists int he group were quick to quip, "I don't need CNC to cut round overs." The fact is neither do I. I cut my first round overs on an RF30. I didn't respond defensively that I could do it manually too.
Instead I posted a short video of making a dozen t-nuts start to finish on the KMB1 in the time it might take them to make one or two and said, "Yep. You can makes these manually too."
I can do a lot with a little, but that doesn't mean I want to. It doesn't mean I want to. I would much rather do it better and/or faster so I can move on to the next project or go fishing.
Really the whole point though of this video series is to help people do a lot with a little. Most of it will be aimed at beginners or even total non-machinists. I hope anybody who isn't a master might learn something even if they only watch it so they can make themselves feel better by finding things I do to find fault with.
I found the same thing in motorcycles. People who believe and spout off, "If it ain't a Harley it ain't a motorcycle." "People who sneer down their nose at Harley riders as "Slobs humping their rolling speed bumps," and the poor guy who bought his first motorcycle that isn't as fast as squid mobile or as comfortable as a pie to pie rider's bike. I've owned a bunch of motorcycles over the years and more than a couple Harley's, and honestly they have all had things that were good about them. I'd ride any one of them again today if I still had them.
Well, I haven't owned as many mills as motorcycles. Not by a factor of maybe three, but right now there are 9 milling machines in my shop. My "home" shop that was never intended to be a machine shop at all when I put up the building. Every single one of them has some value. I like to think about what I CAN do with them and why I keep them rather than how some other machine in the shop is better or how I don't need the features on one because I can hack it out on one of the smaller less featured machines.
Better or easier doesn't mean what you have is bad. Its just better or easier. I can drill holes in concrete, brick, or rock with a 3lb hammer and a star drill. If I have the time to spend I don't "need" a 1" rotary spline drive rotary hammer to do the job. Just like if the bigger contractor has a core drill it doesn't mean my rotary hammer is bad. It just means he can do the job easier, and maybe faster.
You are right though. A round column mill does have a huge deficiency. There are work arounds, and if that is what they have that's what they have to use.
By the way, Thank you. I fully intend to credit you, and Jim and maybe a couple others atleast in the introductory video as inspiration and for helping me clarify my own motivations and goals for doing this. Almost everybody in this conversation except one has been very helpful in that regard.
Reply to
Bob La Londe
... BIGGER through spindle more.
Reply to
Bob La Londe
... BIGGER through spindle BORE.
To many thoughts. Not enough time.
Reply to
Bob La Londe
... BIGGER through spindle BORE.
To many thoughts. Not enough time.
----------------------- You need more bore. I saw a Monarch at an auction with a bore big enough to turn 21" torpedos. No tailstock though, so I passed on it. Or maybe you just need new glasses, that's it.
Reply to
Jim Wilkins
I figger it's much better to have it and not need it than to need it and not have it ... actually the only thing I'd change is to put a 3 phase motor with a VFD on it .
Reply to
Snag
Thanks , you just bumped my ego a bit ... I've found that just about every person I meet knows something that I don't - and need to . The lathe was an impulse buy , I saw it in a pawn shop that I traded with frequently (buying tools , not pawning my stiff) and knew right away that it was put there for me . I waited a couple of months for the price to fall some before I made an offer because I knew there is little demand for that sort of thing in Memphis . It came very well tooled with everything but a motor , and I already had a line on one . As far as motorcycles , I've always thought that it not what you ride as much as it is you do ... my personal choice is Harley's but there are many motorcycles out there , choose the one that fits your needs and wants . Ride on , Man !
Reply to
Snag
I figger it's much better to have it and not need it than to need it and not have it ... actually the only thing I'd change is to put a 3 phase motor with a VFD on it .
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I'd use the extra size if I had it. My mill is only big enough with extra external supports, like hanging the other end of long stock from the ceiling. I think it's big enough to not need upgrading as a beginner's hobby machine but I build practical working machinery up to 16 feet long. The bandsaw mill's frame is 7 feet long. Drilling the wheel axle holes parallel would challenge a 9" x 49" Bridgeport.
Reply to
Jim Wilkins
Bob got upset and stormed off, not me. He must be busy making those 17 videos he spent hours writing about. Why watch a video when you cam just read about it instead?
Reply to
Cydrome Leader
I've done a few videos in the past. Some very seat of the pants one take as it happens sort of things. Back in the early days of YouTube those were quite popular. In fact my most watched video ever was on soft plastic plastisol rubber injection in just such a format. I setup a camera, made some rubber fishing lures, and uploaded it all. It was pretty much terrible in every way including technically about the process. Now people expect a better produced, distilled, and curated video. Some want detailed drawn explanations of every process, and some want you to magically know what they personally want to know and include not one word or grunt that doesn't personally serve them. Obviously you can't do both.
I've spent a while thinking about this project. I've probably been thinking about if for a year. I even dismissed it a couple times as non-productive and unprofitable. It just keeps coming back into my thoughts. I finally started an outline which I shared with a publisher I know. I quickly realized the introduction alone could get bogged down in basics people need to know, but would turn off those who just want to get to the meat of the matter. The publisher's suggestion was to just leave that out and let them flounder with the missing material. I didn't like that. I'm not creating the series for people who already know everything, and I fully expect a large portion of the three people who watch the series to know very little about machining. Of course I can't please everybody, and some I could not give a damn if they are pleased or not, but I do want it to have wider appeal. I decided to compromise.
The introduction will outline what the series is about and show some basic information. There will be supplemental videos along the way for those who need more, and then there will be actual episodes that show individual mold projects. People who already know how they will do everything or have a good grasp of the basics can skip the supplemental videos. They will be invited to skip the supplemental videos, and in those where there are options, the best option and the cheapest option will be presented first.
This format should keep all videos relatively short. Ideally around 5 minute, but some will certainly have to be a little longer. I hope that none exceed 15 minutes with those being mostly limited to the project episodes.
Hence:
1. Introduction: What its about 2. Supplemental: About the machine & its limitations 3. Supplemental: Work Holding & Locating 4. Supplemental: Tool holding and selection 5. Episode One: Making a _____ Mold On a Manual Milling Machine 6. Episode Two: Making a _____ Mold On a Manual Milling Machine 7. Supplemental: The first machine improvement(s). 8. Supplemental: Good enough vs tolerance stacking This may be covered in Episode One instead. 9. More...
etc etc etc... Again, know-it-alls are encouraged to skip all the supplemental videos. Those who think I am full of shit are encouraged to skip all the videos. Those who only watch so they can build themselves up by tearing me down are welcome, but unpleasantness of any kind will be censored in the comments. It would be best if they kept their smug superiority to themselves. Imagine how great it will make you feel to know you are better, smarter, more knowledgeable, more handsome, and have larger procreative organs while I ignorantly blather on without even knowing it.
So that it doesn't get bogged down in waiting I hope to do most of the video and outline work for 1-5 together so that each of those can be published only a few days apart. I don't want somebody to watch the introduction and then have to wait a month for Episode One, and I don't want those who want more help getting started to not have the option to get it before Episode One is published.
I considered dropping all of the first block of videos at one time, but I think that could be just as bad as dropping a single 40 minute long video. It would instantly lose those people who don't have an attention span much longer than a sound bite.
Reply to
Bob La Londe
External supports are a real part of machine work. Whether its machinist jacks on parts that overhang past your vise jaws, or a roller stand 10 feet behind your horizontal band saw.
I doubt I will ever need it, but I positioned the knee mill so I can crank the table over and mount a stand on it to support an extra long work piece on the 14x40 lathe. I think accepting that not every solution is elegant is just part of machine work.
Reply to
Bob La Londe
Many simple VFD solutions leave you with very little torque at low RPM. Variable pulley or step sheaves have the advantage of giving you full motor power at any spindle speed.
One of the disadvantages of pulley sheave gearing for speed control is sometimes not quite enough torque to get everything spinning up without lugging in the highest speed settings. I've noticed this more on a lathe than a mill.
3 phase has the advantage (in theory) of having less motor ripple when you are chasing tenths. Supposedly well regulated DC motors are even better, but I don't know that. Of course being able to adjust speed on the fly quickly and easily to precisely nail your optimum surface speed is a big deal. Particularly on the lathe, and its the one reason I would seriously consider swapping my 14x40 lathe from single phase to three phase.
Some VFDs can be programmed to help with many issues. Increased current for brief periods when needed, slower ramp to speed, soft braking, etc.
Motor selection can also be a big deal. No matter what I do with a VFD I won't get much low speed torque on a spindle designed to turn 24K at 230V and 400hz, but a big industrial 4 pole motor designed to run 1.8K at 60Hz might still have some usable power as low as 90 RPM at 3hz.
Reply to
Bob La Londe
This is a 6 speed gear drive ... there are times when the slowest isn't slow enough , and same on the other end of the speed range . And sometimes you just can't find that "right" speed for the operation . Having a power feed has lessened some of those problems but still sometimes it's a compromise . <<I've been out "gardening" all day and I'm beat! But everything but one strip is ready for planting , that section was a bit too wet today.>>
Reply to
Snag
...I think accepting that not every solution is elegant is just part of machine work.
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Elegant??? I just did a metalworking job on a doormat on the hood of my truck.
It was the answer to a question I've mentioned here several times, how to bend tubing to an arbitrary large radius. My Sterilite laundry basket's handle broke while carrying a large load of wet insulated winter clothes out back to the clothesline. 3/4" EMT is the right size to replace the handle and reinforce the rim around it, so I tried matching the basket rim curve. It turned out to be very easy since the feel of bending changes when the metal yields. I made a series of slight yield-point bends with a conduit bender and controlled the radius by the spacing between them, judged by eye. It looks like one continuous bend.
The truck hood was just a large handy outdoor bench to drill the attaching screw holes.
This was the fifth basket I've broken at the handle, and time to find a permanent solution.
Reply to
Jim Wilkins
I'm not a big fan of gear head mills, but I have one and at one time I had another. (an RF45 clone no less) Most folks convert them to belt drives and put a two or three speed pulley on them with a bigger 3 phase motor. At lower speeds you will wonder if your motor is running it will be so quiet compared to that gear head noise.
Reply to
Bob La Londe
Anyway, I just wanted to let you know a VFD and a 3 phase motor is not a magic bullet that just takes care of everything. It can take a small amount of learning and planning to wind up with a solution that is optimum for you.
Reply to
Bob La Londe
Well , I've had the mill 14 years now , I'm in no rush to do the conversion .
Reply to
Snag
Anyway, I just wanted to let you know a VFD and a 3 phase motor is not a magic bullet that just takes care of everything. It can take a small amount of learning and planning to wind up with a solution that is optimum for you.
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Do you think a VFD is useful on a belt drive machine? I converted my lathe and surface grinder from 3 phase to single phase, and kept the original motors.
Could a VFD perhaps find a speed that eliminates chatter with a parting or forming tool, or is there a good reason to run a back-geared lathe below 55RPM? I can't instantly reverse the lathe due to its threaded spindle and already thread up to a shoulder with the belt clutch.
A factory option I don't have was a two-speed motor that gave a low speeds of 42 and 27 RPM on this 10" lathe.
Reply to
Jim Wilkins
I have to think about that.
Parting is tricky. I've found geometry and rigidity are a big deal with parting. Of course feed rate and RPM are a big deal two.
It might have some benefit if only for being able to adjust rpm on the fly to stay closer to the right surface speed.
Overall I have to think about it.
There are lots of reasons to consider your motor and voltage source.
One reason that motivates people is cost. Generally a single VFD is cheaper than a new motor or an RPC. For multiple machines an RPC can be cheaper than multiple new motors.
On my high rpm machines its the easiest way to generate 400hz
Reply to
Bob La Londe
If you do not thread often with the compound you may find replacing it with a solid block of steel may help with parting.
Another is placing a jack under the parting tool.
Probably number one first thing to try if parting is a problem is snugging up all your gibbs so they "just" move easily when properly lubricated.
Doesn't hurt to lock the carriage in place either. I do that for harder parting and facing. A thin blade will still flex and walk if its not well supported and is ground improperly, but it eliminates carriage movement from cutting forces.
There are other tricks, but I really have no experience with them. One is a flexure style parting tool holder. It seems counter intuitive to me, but they used to be a commercial tool used on lighter lathes for parting. Winky's Workshop did a video on it not that long ago. I believe he made his own. I don't recall having watched the video, but there was a conversation about it over on Home Shop Machinist.
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I don't sit around watching videos all day. I've got a Fire stick on the big screen TV, and I put YouTube videos on subjects I'm interested in on the big screen while I have my morning coffee and take care of morning chores before heading out to the shop. Makes great background noise, and quite often I learn something.
Reply to
Bob La Londe

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