I was talking with someone the other day who wanted to have a blue sky conversation about what a set of DIY CNC Mill Castings might look like. The idea was, if you could build a set of castings for the hobby and light industrial market, what features would make those castings ideal? This was strictly an over beers kind of a chat, and I love a blue sky conversation as much as the rest, so I told him I’d write it up on CNCCookbook so that my readers could comment on it.
Just to be clear, here are the market requirements I am targeting:
– Suitable for hobby and light industrial market
– Better than what you can convert. Better than the average RF-45 CNC conversion, for example.
– Capable of being set up for sale as a completed mill, a raw set of castings, or parts kits.
That’s a pretty short list that we can deal with.
Here’s what I came up with:
1. Work envelope similar to Tormach or RF-45. For light industrial, you need the mass if nothing else. Besides, there’s lots of good smaller mills and I’m not real sure how you get an advantage over them. A better bigger mill still has some wiggle room.
2. Set it up for linear slides instead of using box ways. This greatly reduces the requirement for hand scraping. You can mill the beds for the linear slides. Typically, you want a precision floor and one precision edge that the slides will butt against. You’ll also need the hold down bolt holes. Probably be a good idea to make a deal with a linear slide outfit since they all have different sizes. If you wanted to make something generic, just machine the one wall and floor and leave it to the builder to put holes appropriately. I think this would be popular as well as resulting in a much higher performance mill. Done right, I don’t see why it would need to be overly expensive either.
3. Take a careful look at the base and saddle of commercial VMCs. They are shaped totally differently than cast hobby mills in order to support the table properly at the limits of travels. There’s also a lot more beef on everything. Think about adding more beef and adopting the shape of the commercial VMC castings:
4. T-Slot table is a good thing. Needs to be machined true.
5. Think about how to protect the linear slides and ballscrews from swarf and coolant. Not that hard to do a set of way covers which would be a nice kit to offer. Need to machine some mounting points in the castings.
6. Think about home/limit switches. How and where will these be mounted? What type will be used? Will need to machine some mounting points. The style used on the Industrial Hobbies mills is straightforward and relatively contamination proof. Make your mountings compatible with something like that, offer a home/limit kit, or offer the drawings so people can make their own.
7. Think about the CNC motor mounts and ballscrew mounts. This is not all that hard and need not be precision. After working through my Industrial Hobbies conversion, I can see where you could make it amenable to a lot of flexibility. With that said, you should offer a kit that’s ready to go.
8. Think about leveling. It matters hugely for setup, accuracy, and tramming the mill to squareness. Yet, most mills in the world leave it as an afterthought. This is an area Tormach invested more time in. In your case, if you plan to sell a kit, you’ll want to set it up so the buyer can deal with it.
And now, for the most important part. The heart of any mill is the spindle.
The specs for the Bridgeport spindle are about perfect in terms of rpm range for a hobby machine. The Tormach uses a similar range for that reason, and it gives it a huge advantage over the average 1600 rpm RF-45. You want 0-6000 rpm and some way to ensure decent torque throughout that range. A 2 pulley step pulley system and a good vector VFD are about right in today’s world. I would be targeting 3-5 HP, so think about motor mount on the headstock. You’ll want to mount it to a plate atop the pulley stack. It wants to be easy to change pulleys.
You want provision for a powered drawbar. You can try the Tormach adaptation for R8 via TTS or something else. You don’t have to solve the problem up front, but you need to make sure you’re not painted into a corner. In other words, there must be room for the powered drawbar to be mounted on the motor plate. It needs to interact with the spindle in such a way that it doesn’t load the spindle bearings.
I’d set up for a spindle cartridge like the Tormach guys use. Source a cartridge from China to offer, but make the hole a little larger to give it a range of possibilities. People are gonna want R8, although I personally would suggest a 30-taper option as it is a much better taper for the machine.
I’d say that’s a good overview. I’d offer several styles:
1. Raw castings–you do your own machining. There will be an audience for this, so why not?
2. Machined castings–you add all the outboard components like linear rails, ballscrews, limit switches, spindle cartridge, etc..
3. Machined castings + matched rails. All they need to do is add ballscrews, motors, limit switches, and spindle.
4. A series of parts kits to go with #3: Ballscrew kit w/ NEMA motor mounts, Spindle cartridge, Motor mount plate set up for the desired motor style (the face options are plentiful and people will appreciate choice so they can scrounge the best deals), and a spindle cartridge kit with appropriate pulleys. Should be a 3HP and a 5HP motor option as well. Lastly, a way cover kit will be welcome.
5. Finished mill kit. Pimp it out all the way. 5HP, Servos not steppers to take full advantage of those rails and get some decent speeds up, etc.
Later in the game, you can add power drawbar kit, ATC kit, and possibly a one shot oiler kit, though the rails can be greased too.
That’s how I’d do it, and depending on price, you’d wind up with a pretty sweet mill.
Now it’s your turn. What do you like about this proposal? What would you do differently?
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I’ve been hoping for something like this for a long time. The only thing I’d is provisions in the castings for easy moving. Ideally a single person and an engine hoist could assemble or disassemble and move it.
Good call. Maybe holes for lifting loop to bolt in at appropriate locations.
I think a good 4000lb machine would be ideal. Don’t car for anything a engine hoist can lift we have enough of that these days. I love my 7000lb bed mill. It was cheap for only $8,000 and has 20x40x20 travels. Frankly I’d love to build a pull barn and scoop up all the old machines like it and retrofit them the way I want with HGR45 linear rails. For the most part you can find them for $3-$8000 locally if you look and a good casting would cost that much.
Pallet jack, Maybe.
David, ATC is easy once you got power drawbar. It’s pretty self-contained and just needs a mounting pad on the column.
Bob, That is an ambitious project! At least it will probably bring forth a lot of interesting comments and ideas. To do a good functional machine will take a lot of thinking, and planning to avoid those nasty little traps. I have been offering a few ideas to my Godson who is at Uni about building a router or light mill, but I think the small toys are easier to buy, and accept the limitations.
You are obviously looking at a serious level machine here, and that will cost serious dollars. However, it might be a way to produce a real performer that caters to the real needs of people making smaller parts.
Several things spring to mind though. While I quite like R-8 tapers, I feel it is worth looking at the more usual type of multi finger pull draw bar not screwed collets. If you are looking at rapid changing that does have advantages, but maybe a little complex or costly. I suppose it would not be practical to use no 40 tapers, they are a very good convenient size and can take all manner of tooling. I suppose one could get used to 30s!! Once you have become used to the standard 3.5 inch per foot taper, it becomes a way of life. for quick easy tool changing. I have used the good old Bristol Erickson quick change spindle nut fr 30 years on a Shizuoka with 5 HP inf. variable speed change like the Bridgeport and 5 HP. and very satisfactory.
I like your idea of the higher speed spindle cartridges. 6000 or even 8000 RPM would be perfect for many of today’s tools and it speeds up the production and improves finish.
How is the rigidity with those rectangular 4 row linear bearings? I understand that it cannot be as good as well fitted solid box ways, but the friction would be very low. I know they are very common on the high speed machining centers.
Your comments about features to design into the main castings are very wise! Even little leveling pads to assist early operations. In fact, it might pay dividends to supply say base castings with both under and upper surfaces machined or ground on a large vertical spindle surface grinder. They rip metal off and to have key items with a good flat reference surface to start with, would make a lot of work much easier. After all, many home shop guys do not have the machining capacity or the wherewithal to handle such large items. It would be a good idea to make the surface that the main column bolts to, a bit lower than the machining for the guide rails, so it is easier when doing checks.
You have started what could be an incredibly interesting discussion group. Design for ease of manufacture, as well as basic inherent rigidity and stiffness. No doubt careful input about the best grades of iron to use, and is it cost effective to have the castings stress relieved to reduce or prevent eventual warping etc. Consideration about the grade and accuracy of the ball screws, not el-cheapos. Another thing is the attention that must be paid to the bearings supporting the lead screws to avoid inevitable backlash. I used deep groove matched angular contact bearings with very slight pre-load in my Bridgeport retrofit 34 years ago and they are still as good as the day they went in.
I think that is enough for one note. If you can get a couple of top flight machine tool design guys to assist, you could come up with a real winner. One set of drawings, one basic set of castings and the ability to make choices in lead-screws, motors, and other easy to do items.
I for one will be following this with great interest. Being able to fit different spindle cartridges could prove to be a real winner. Also remember a few weeks ago you ran an interesting article on a guy who is making said items. There are also a range of cheap water cooled high frequency units available up to 24,000 RPM, which could open up some amazing opportunities to some users. You have many options here, and I wish you the best of luck in getting things going. Fabulous!
There’s already a Chinese gentleman well advanced with a mill which sounds very similar.
See: http://madmodder.net/index.php/topic,8456.msg91037.html#msg91037
He’s already got 2 sets of castings ageing.
Phil, it’s interesting but I don’t see any pictures?
Hi Bob,
Sorry – I didn’t realise that you had to be a member of the MadModder forum to see pictures.
I have them downloaded but can’t see a way of uploading them to you. They do look very nice!
Phil.
One thing that i would not dismiss is the Boxed ways. There is a little more work to the manufacturing of them, but offer a much more rigid system,plus an option for the end user to adjust “slop” as machine loosens up.
The boxed way debate will be waged endlessly, but my thinking on it is that this is just not a big enough and beefy enough machine to see the benefit. Pretty much all the smaller commercial VMC’s of recent design are using linear slides. That’s telling us something we ought not to ignore. The other thing is the cost of manufacturing. Remember, we’re not likely to get hand scraped box ways on a machine like this. So, are we better with milled ways or linear slides? I think the latter, but the Tormach is an excellent counter-example.
I love the idea of a well thought out box way or linear way machine with ATC, rigid and with a good work envelope. For my work, I also need very good ballscrews. If you were to do this kind of thing, I’m wondering what XYZ travels other people would like to see too. The biggie is; what would a guy be willing to pay for such a beast?
The problem I see with a casting set is that the buyer has to have machine tools big enough to handle the size and weight of the castings. Few home machinists will have those machines.
Next if you do box ways the buyer will have to know how to scrape to 3 axises of precision. That is not a skill you learn over night.
Even if you do linear rails you still have to maintain 3 axises of precision.
If you provide a machined kit then the supplier of the kit has to maintain the precision and that will cost big bucks.
If the cost comes to greater than 75% the cost of a Tormach then You are better off buying a finished machine that in just a few days you can be making parts on it and not the monhts it will take to build one your self.
This not to say it can’t be done, just that is will take lots of time and money to do it.
Dave
Would a precision metal frameworks filled with epoxy concrete be a viable option over iron castings?
– Aggregate could be sourced at the customers location cutting shipping weight.
– Larger structures could be created using lighter metals then re-enforced with EC.
– Epoxy concrete is supposed to provide more mass and vibration dampening than iron castings.
– Less metal to machine if you focus on surfacing reference edges of the metal framework.
I have also wondered about using concrete as an easy way to add heft and rigidity to a DIY mill. The coefficient of linear thermal expansion isn’t all that much more than grey cast iron (http://www.engineeringtoolbox.com/linear-expansion-coefficients-d_95.html) and it’s cheap and easy to make on location. Even if you stabilize it with some sort of epoxy you can gain a lot of weight for not much money.
If doing the castings, my preference would be to eliminate the need for an epoxy granite fill. I like epoxy granite in a case where rather than castings, a machine is being fabricated via weldment. It is also an excellent way to add dampening to an existing machine that could benefit from more.
It does, BTW, need to be epoxy granite and not plain concrete. You can accomplish some value with concrete or sand filling, but mostly, it just makes things heavier moreso than it increases vibration dampening.
If you’re curious, this was the article on my E/G fill:
https://www.cnccookbook.com/CCMillEpoxyFill.htm
Mikini sells what you are describing for about $10K. The OEM electronics on mine have been problematic, but the base machine is a solid performer. I’ve replaced most of the OEM electronics with Flashcut control and drivers, along with some other DIY mods.
http://www.mikinimech.com/Mikini%20pricing%202012%201.pdf
You are almost describing my Haas TM-2P. Check out the weight and hp. The machine is way over priced than what it is worth. I have my Haas running Sprutcam just like a Tormach but its bigger. I have thought about how much I would like to build something in that size range.
I love the idea but I would target differently. As I see it, you want a modest new machine, you go with Tormach, and if that’s not enough machine, there’s Haas. I don’t see a lot of sunlight between them, less so if you open the competition to used machines.
One direction I’d go is smaller. I suspect there’s a lot of guys out there who have more money than space. A Tormach requires a LOT of room for a home shop. I think something like the Haas Office Mill could be interesting at more of a high-end hobbyist price point.
Second line of inquiry is to think outside the bedmill box. What about a horizontal? It’s got much better chip clearing, which might alleviate the need for heavy flood cooling which makes the machine easier to co-exist with and enclose. But the big thought is that a horizontal could be easily built as or turned into a lathe by sticking a gang tool block on the table. If it could be built as a lathe (similar to how the spindle assembly is largely shared between the X2 mini-mills and 7x lathes) you get more volume which drives unit costs down.
Another thought is that the real market for these castings might not be end users who by and large won’t have the wherewithal to machine them, but for intermediate builders. You want a cheap machine, there will be guys in China who finish them to a minimal pricepoint. Or you can get a shop in the US who does a full servo name-brand build.
Bob,
Great thread. My thought is a lot of heavy hobby or light commercial people need to make specific parts. A bicycle guy might want a long X to deal with frame members etc.
So, if we had a long and short Y axis base, a saddle set up for long or short X travel, a column set up for regular and tall applications. A modular riser block might work also. As another poster mentioned, maybe another column design that supports a horizontal spindle.
In my mind, these machines would be economical enough to build as specialized machines. So, instead of bolting on a trunnion table, offer a casting set for an integrated trunnion table instead of the common T slotted or grid bolt pattern style table.
Course all the castings would have a lot of amenities to allow for many accessories to be bolted on. A pad for a tool changer, another pad for a probe, lots of beef so a lot of variation can be accommodated in mounting thrust bearings, motors, guards, covers, energy chains etc.
As a compromise on the box vs ball way debate, offer crossed roller ways.
And the last point, build interest in the next iteration of control software. An advanced hypothetical “Mach4” that might support commercial level uptime. Since this type of software should be easier to configure, the only impediment to building a nice turn mill, bar fed mill, or mill turn would be nice castings to base a build off of.
Aloha
Peter
Having owned both a bench top mill that I converted myself and currently owning a VMC, I believe that there is very little ground between the too. Let me explain. If you ask yourself the question how fast do I need to make parts, it will dedicate what you need in a machine. (Assuming the machines you are considering both have an envelope large enough to accommodate the largest part you are going to make.) For me, my bench top was large enough but when I went from making ones and twos, sometimes for me and sometimes for profit, to making 20 or more it quickly became evident that I couldn’t make money tending to a machine with no tool changer and a max spindle speed of 2500 rpm. Casting rigitity never once held me back more than doing a finish pass. I did just about everything I could to that mill to make parts faster. Servos, ballscrews, bearing, lapping, one shot oiler, flood coolant, pallets. Every dollar I spent on it had a diminishing return because I was always limited by the Material removal rate and having to change tools. Even if it just had a tool changer with a relatively slow spindle could easily do the batches of 100 I do now. The reason is because my machine doesn’t run all day. I have spindle time to spare. I would be fine letting the machine cut all night if I didn’t have to change tools every few minutes. My point is this, If you need to make parts faster than a Tormach w/ tool changer makes, then you need a full VMC. The decision line is that clear to me now looking back.
Now having said that I realize that there are other consideration. One might be that it has to fit in your home garage. I do wish that I could be spending time with the family and just step out for a few minutes to change a pallet. As its still a part time jig for me and many others wanting to make parts, you can just about count on evenings away from the family if you get a full size machine center.
There isn’t much difference in cost between a Tormach and a used machine. I picked my up for $6500 with A LOT of tooling and a pallet changer. A screaming deal I know but I could have paid double and still been in the same price range. You do have to consider if it will need work but if you are going to convert another mill or casting, your in for a lot of work anyway. Pay a technician a couple hundred to check it out before buying one and you will be miles ahead. Even an old machine will out cut a benchtop size.
I didn’t mean to ramble on but if you would like more of my thoughts, look me up on youtube. I am slowly doing some vids about upgrading to a VMC. Now having said all that, if I was going to design the perfect casting it would have 20×12+ inches of fully supported table travel, tool changer, require no additional machining more complicated than a hand drill and tap, and all the motor brackets, switches, ballscrews advailable pre-made because its hard to machine those parts without a functioning mill and lathe. It would be designed around electronics that could be run from standard home power.
Peter,
Good ideas. I would like to add the the mount for the column and the head could be square to allow for the same castings to be used for both the vertical mill and the horizontal mill/lathe. This would even allow for the machine to be switched for an odd job.
Back to making,
Chris
Got an email from a knowledgeable friend who suggests that one problem with selling unmachined castings is there may be an undiscovered void in the casting that is not revealed until you attempt to machine them.
Good point!
Bob,
Quality castings rarely have issues. How easy it is to source good castings nowadays is questionable though. I based some of my comments on observations at the Milltronics factory in Mn. I saw them fitting many combinations of castings to build specific machines. They had a well defined model list so the castings were not machined in an extremely flexible fashion. Still as long as the column to base bolt pattern is well thought out, it will allow the easy interchange of various castings.
Once we got a waterjet, our need for lots of Y axis travel just about disappeared. If I could build a traveling column mill with a stationary table, that would be another neat configuration to build.
One more point, a carousel tool changer with a geneva rotator, a pneumatic positioning cylinder, a modular gripper set for R-8, 30 and other tapers would be neat. Maybe somebody could make a small business of designing and offering parts or complete units for sale.
Aloha
Peter
Peter, zbot (http://www.zbotllc.com/) builds Tormach’s toolchanger and could possibly be an OEM source.
Said knowledgeable friend is actually in the machine building business and speaks from his own experience with castings, but I can say no more.
Cheers,
BW
A niche market might involve a wide arrange of standardized interconnecting cnc modules. These modules could be assembled at need for individual projects. Need more z travel order the 2x column with ballscrew. Need a faster spildle or 4th axis? Swap out the head and the y table. Need to do 3 opperations on a long run part? Install 3 spindles on one chassis, one for each operation instead of 3 different machines.
I want to start building machining centers like they are lego sets. The parts need to be a bit more modular out of the box.
Apologies in advance, I looked at Mr. Warfields 8 point plan and took exception at every point.
Several people here touched on what I think is by definition the solution for the problem that you lay out.
In a word my candidate for this solution is sheet metal.
I will give you a moment for you to stop screaming before I point out that IF this a home hobbyiest,diy sort of guy with a hole in his shop big enough for ANY (any) mill, the sheet metal shell that the UPS man delivers (think $50 – $300) . The handyman carefully fills it with portland cement, and anchors ground steel (tool steel) barstock of an appropriate size for rails, and steel mounting points for motors brackets and all that(again think $50 – $300 per axis).
1. Work envelope similar to Tormach or RF-45.
If you can make a 3d model in blender the sheet metal shop would do it as any shape any size. I want my Haas TM-1 with fins
2. reduces the requirement for hand scraping.
ground barstock eliminates it!
3. Take a careful look at the base and saddle of commercial VMCs.
OK, fins and a fat saddle.
4. T-Slot table is a good thing. Needs to be machined true.
no.
We all grow up to be “platen style machinists”.
5. Think about how to protect the linear slides and ballscrews from swarf (he ment chips)and coolant.
Sheet metal covers
6. Think about home/limit switches.
Lets install extras all over this thing, they will come in handy later.
7. “need not be precision.”?!?!?
They are in my shop
8. Think about leveling.
Think about what wet Portland cement does.
None of those are the real reason however. Entry level tools like Tourmach and Hass mills are cast, machined and shipped in pretty short order. Companies like Mazak in Kentucky, cast their bases and leave them sitting on their back lot for 14 years before they are machined and scraped. That’s expensive but they have a very good reason for doing it. Cast iron “ages”. In 14 years the metal changes, moves, and begins to develop a set of damping qualities.
I realize that the Monarch EE castings were not, but that was wartime and they used steel and other tricks to overcome those problems. There are other ways to address vibration.
An active system with an Arduino based driver would be my suggestion.
Sorry for being so argumentative.
Chris Cowen , Model Maker
Montara CA
Chris, nothing wrong with being argumentative if you can make your points in a logical, unemotional, and civil way. Let’s have a look at them.
1. A TM-1 with fins. Well, the thought was about work envelope, not aesthetics, but to each his own. The TM-1 has a slightly bigger work envelope at 30 x 12 x 16 vs 18 x 9 1/2 x 16 1/4. But do keep in mind, it is a hobby mill and rigidity requires mass commensurate with volume. In other words, the cost goes up in direct proportion to the volume. One of many reasons the TM-1 is not cheap.
2. Ground barstock does not eliminate it. Ground ways are typically not very happy either from an accuracy standpoint, a friction standpoint (the high low spots of a scraped surface help the oil to form a film), or a wear standpoint (directly proportional to friction). Scraped or linear rails works best.
3. Good, we agree.
4. More color needed on this “platen style machinist” concept.
5. Sheet metal with scissor linkage are much nicer, but very expensive. A hobby mill just doesn’t need that much durability, but hey, it’s your nickel. I’d much rather spend the extra cash towards linear rails than sheet metal way covers though.
6. Extra home/limit switches?
7. Why put undue precision into something that doesn’t need it? The precision I speak of here is not the ballscrew, but the mounting of said ballscrew. It really doesn’t need the precision.
8. If you want to fill your sheet metal with portland cement to make a machine, go for it. My machine is actually filled with epoxy granite, so I’m pretty familiar with the approach. The problem is, the portland cement is neither very rigid nor very good at dampening vibration. You’ll have to use an awful lot of it and make a very large machine to succeed in having reasonable rigidity. You can build a very nice machine if you’re willing to use something other than portland cement that dampens vibration better (big fan of the epoxy granite), and welded construction using thicker material than sheet metal. That can result in a real machine that’s way beyond hobby grade. Active systems have been played with quite a bit. They can help, especially with chatter, but these other approaches work better.
BTW, as you are interested in active vibration dampening, there are related technologies that can age metal much faster. I like the steel weldment approach as it doesn’t need so long to age. FWIW, Tormach castings are aged as well. 14 years> No. I’m skeptical that Mazak ages theirs that long too though. Sorry to be so argumentative!
I think it could be pimped out without servos. Having run some of the larger steppers out there, they will slide my Asian cast Mill Drill around at 350ipm, and hold really tight tolerances.
The limiting factors of my mill drill are not feed rates or accuracy of steppers. Higher spindle speed was a big one. I ended up with one of those 2.2KW $300 engraving heads from china. It’s been doing amazingly well. Although tool changes are a pain. Automatic tool changer would be really nice.
If you think about a hobby guy. Cheaper stuff is usually smaller diameter (.125 inch) stuff. Running blazing fast spindle speeds keeps the MRR high and machine deflection low with the lower consumables cost. To do that you need the fast spindle and to move quick, oh yeah, and Gwizard… 🙂
Quick change tooling would only add to that…
I came across this page looking for casting ideas myself. I have several mills all in different stages of upgrades towards CNC. In fact I could just knuckle down and opt to get them running since all the parts are here. My hang up? They’re not ideal for what I want and I don’t want to redo anything or pay twice which I’ve already done in previous changes. I would like to first get a hold of aricas ground way base because the base is the largest I am aware of and will literally fit all three of my mills in extending the y axis to 13”. One of my mills already has one. This would be an upgrade I could see many wanting to do if they could buy a replacment base for a few hundred. Secondly I want a new mill head. I don’t want to modify my existing one I want a new bolt on with integrated 5th axis ready to roll. While making a new casting entirely it seems to me retrofitting new heads on what’s out there already makes the most economical sense in providing what the vast majority want. A 12x12x8 cast head with a Nema 34/42 flange coming off the rear of the head and a 4140 fine pitch HD gear that can be mounted between the head and the columns existing z slide as a simple add on option. I’m considering a custom built head made from hardened steel that is epoxy granite filled for weight and ability to absorb vibration. You can find a number of prebuilt belt drive spindles on Alibaba for $700-$800 that look near identical to the haas spindles with a 10,000 rpm capacity. A head where one can Machine their own top cap according to their motor, power draw, atc specs, etc…, that they intend to use. Going back to your idea we’re talking about a sturdy machine. If we look at the aricas existing columns they could also be retrofitted. Made in Taiwan already they are seriously heavy duty. I’ve ran 1-7/16 cutters and 5” shells without any issue weighing in at 1200lbs (see PM833t). I believe my thoughts would make them durable enough to handle at higher rapids and suitable for everyday light industrial use. Retrofitting seems most cost effective granted not a new better design from scratch but a suitable upgrade that would probably have many considering spending $500 to $2k depending how much retrofit they wanted in their particular machine. This is the route I would go when a quill would be considered obsolete. Personally I like the idea of keeping a quill in applications where both manual and CNC use may be integrated. Let’s be clear, “I Love Manual Machining just as much”. I’ve looked all over for conversion spindles for belt drives that keep the quill. Nothing out there I could find hence the reason it makes more sense to just replace the head with a much better spindle assembly that utilizes larger AC bearings if I’m going to lose the quill anyways why on earth would I want to retrofit a spindle that only uses 35x72x17 and 30x62x16 bearings? It makes little sense it’s like lipstick on a pig. Perhaps the biggest weakness in these smaller mills is arguably the spindle right next to overall weight. So redesign or retrofit? I think if a good product was available retrofitting would probably be the go to. Thanks for sharing this page it’s very informative.
I came across this thread a couple months ago, and I agree that there is not a ton of space commercially to try and run a company marketing a product between the Tormach and Haas lines. I think the opportunity lies for an open-source DIY product with specifications similar to the Tormach.
If the designs are freely available, I bet you’d see enough DIY guys follow the specs to build their own machines, since that would allow them the added benefit of other people with essentially the same machine for a support community. Over time that would allow you to build enough of a user-base for a company to come along and mass produce the castings as a kit (similar to how things have worked out with the RepRap community for 3d printers).
I’m working on putting together something open source, that I hope to eventually open up to collaboration on either Hackaday, Github, or the likes, but it’s not quite far along enough to open up for collaboration yet. I’ll try and update this if I do get to the point of opening up for collaboration or releasing prints.
There is also a company i found based out of China that makes OEM machine frames (http://www.zzsmartech.com) that quoted me a fully kitted out frame (HiWin linear slides, metal way covers, ballscrew drive, basically everything except the motors, controls, enclosure, ATC) XYZ 330*220*320 mm, table 210*690 mm, BT30-8000 rpm spindle for $5500 FOB. It doesn’t have the VMC style saddle shown above, but neither does the Tormach. They offer enclosure and ATC options as well for an additional $1000 each. It’s something that might fit the requirements for someone else out there.