designing an RFP for an entry-level loadout (crossposted to Virtual Machine Shop forums)

This is too extensive a subject to cover with newsgroup posts. Enlist the help of one of the N.J. posters here who knows something about machine tools. One such is Ed Huntress. I think he doesn't live far from Paterson. There are probably others too. One of his first questions will probably be "what do you want to do/make/accomplish with your machine tools?"

Rather than buying a drillpress I would recommend a good used Bridgeport type mill with a digital readout (DRO) which will give you your drilling capacity as well as milling. The digital readout gives you accurate positioning and makes life easier for laying out hole patterns and the like. Some DRO's will automaticly compute the hole locations after you punch in the hole circle diameter and number of holes.

I'm not sure what you mean by a cnc cutter but any cnc machine that is a decent unit is going to go for much more than the figure you suggest.

YOu should first decide what you are going to cut with the machines, how big and what material. Aluminum is much easier to cut than some other materials. The other thing you must consider is what tooling you will need to go with the machines. For instance with the lathe you would possibly need a steady rest, three and four jaw chuck, maybe a collet nose, and a bunch of toolholders and some type of quick change toolpost, as well as some morse tapers and drillchuck.

A bandsaw will probably be handy to have unless you order you metal precut to size. Again, it all depends on what you intend to do in the shop.

John

??? There are lots of things which are CNC. There are lathes, Miling machines, wire EDM, plasma cutters, waterjet cutters, etc.

Assuming that all machines are for roughly the same size of workpieces, I would consider that the lathe should cost significantly more than the drill press, and until we know what kind of CNC machine you really have in mind, no bets there -- except that CNC tends to do nasty things to the cost -- unless it is done as a home conversion project.

I would consider a milling machine to be a good thing to have in addition to lathe and drill press. *Maybe* this is what you are calling a cutter. But for pricing -- bear in mind:

1) a drill press moves in one axis (the drill bit moving down towards the workpiece while rotating, 2) the lathe moves in two axes (cutting tool moved along the bed towards the headstock (to form a cylinder or cut threads) and across the bed to adjust the diameter, or to face off or part off the workpiece. The cutter moves slowly relative to the rotating (spinning) workpiece, cutting material from the surface of the workpiece, and leaving a cylindrical surface -- either on the OD or boring an ID. 3) The milling machine moves in thee axes (X and Y to position the cutter relative to the workpiece, and Z to determine depth of cut. The cutter in a milling machine rotates like that in a drill press.

For each axis, you need more positioning equipment, and more rigidity, so the order of cost for similar workpiece sizes would be:

1) Drill press (cheapest) 2) Lathe (more expensive) 3) Milling machine (most expensive).

Add factory CNC to either of the latter two and you do terrible things to the price.

What sizes? And are you talking *new* prices, or used machine tools?

Your prices seem high for a typical size drill press, perhaps a reasonable value or a bit low for a medium size lathe, and *way* too low for whatever kind of "cutter" you want with CNC -- except perhaps for a little benchtop milling machine with CNC built from a PC.

You need to know what size of workpieces you intend to work on. From that, you can select sizes of machine tools.

A good sized lathe or milling machine should have reinforced concrete or a filled end-grain wood floor above concrete. Bench lathes and milling machines just need a respectably strength bench -- and most drill presses (before you get into radial drill presses) will go just about anywhere.

You will need three phase electrical power (240 VAC three phase) for serious machines, though you can find machines to run on single phase 120 VAC at some loss in capability.

If you get into serious industrial sized machines, you will need coolant -- and if you use mist coolant you need ventilation to keep it out of the people's lungs. Serious CNC milling machines and lathes are enclosed to keep the splashes of coolant under control.

If your "cutter" is a plasma cutter -- I suspect that you will need special ventilation. Let someone who works with them answer that.

What do you need it to do? Until you know that, what might work very well for one size of project will not do anything satisfactory for a larger one.

Unfortunately, until you get into *serious* industrial machine tools, most of what is available *new* will be Chinese imports, and all of these should be viewed as a "pre-assembled kit". You have to take them apart, file off burrs, and clean out sand and grit before re-assembling and using them. And this requires someone who knows the machines.

Good Luck, Don.

Do you have a shop now? If you do then talk to the people that currently use the shop. If not then there are a lot of tools needed before getting a lathe. Things as some sturdy benches, good vises, a metal cutting bandsaw, a drill press, bench grinder, small belt sander, small torch, mig welder.

I disagree with John on buying a Bridgeport mill instead of a drill press. If you have a mill, someone will be using it for milling and someone that needs to drill a few holes will have to wait. And a drill press is something you can give a few minutes of instruction to a 16 year old and then let him/her use it. Suitable drill presses are not expensive.

Dan

(Dad mode)

The first step is to find out what questions to ask.

What do you anticipate building? From there you can determine what it will take to get there. You are only concerned with machine tools. Does that mean you already have the hand tools, workbenches and storage cabinets? Is your school going to put in the power required to operate the machines? Who is going to provide the training (safety and operation)?

Time for a road trip. Reach out to your brothers and sisters at schools that have good robotics programs; visit their shops, see what they are building, get copies of their safety training (keep in mind that your college will probably not let you operate without it), and determine what will work for you. If you have time, go to the Cabin Fever Expo in January to look at stuff and talk to people that make things.

At that point you may be able to make a shopping list. 6.5K will not get you much in the CNC world.

If the terms of your grant allow it, you would probably be better off finding a used machinery dealer who will have mercy on you and fix you up with a package that includes the tooling you will require to actually make anything with the machines. I do not know any machine tool dealers in north Jersey. Perhaps one of the other guys up north (Joe?) can point you to someone relatively honest.

If you ask nicely you may find a retired professional that will look in on you occasionally for the good of his or her soul.

Olin College of Engineering does a lot of robotics work; here is a link to the machine shop:

Harvey Mudd on the west coast:

Fortune favors the prepared.

Kevin Gallimore

Kevin Gallimore

Gentlemen

Many thanks for the informative and helpful suggestions. I feel more enlightened already.

To business;

Re Ed Huntress: Sounds like an excellent person to get in touch with. Any contact info for him?

Re used: not an option for educational institution purchasing

Re cnc machine: what we're looking for is a cnc router. Examination of relevant websites

reveals that the price is unfortunately closer to what axolotl says. However, something like this seems like a good start and will probably be a good fallback position if, as I suspect, we conclude that we are biting off more than we can chew.

Re: checking out other schools - an excellent suggestion, but not entirely certain it's in our timeframe. Will let everyone know by next week.

Still wondering if there are any brands I should reject out of hand. Given my lack of relevant experience I need some way to eliminate obviously unsuitable bids.

Also, are there "desktop" versions of any of this stuff for relatively small work?

Again, many thanks to everyone for their intelligent and useful suggestions.

Joseph Stavitsky Secretary DaVinci Robotics club Passaic County Community College

I will forward a link to this thread to him. He has been away from this group for a few weeks. I did get a nice picture of a bluefish he caught the other day so I know he is alive and fishing.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

Here are some examples of what is available:

Larger, more expensive machines will handle larger parts, which is why people have asked you what you want to make. They start very small:

Personally I'd want at least a mill-drill with a table TRAVEL long enough to drill all the important holes in the largest frame component, without having to unclamp and move the workpiece which destroys accuracy. Mill-drills are good for two-dimensional parts made from sheet or plate. If you expect to work on tall, bulky parts, reboring a small gas engine cylinder for example, a knee mill is much better.

Mills make the framework, lathes make or modify the power transmission components. What are your largest wheel or pulley diameter and longest shaft length? Power transmission parts are standardized and may be easier to buy than make, so the lathe may not be quite as important. In my opinion the minimum practical lathe is 9" - 10".

I'd avoid the lathe/mill combinations, especially for a team.

jsw

Jim: Really loving the Sherline site, highly informative and looks like a good start. Do you have hands-on experience with their products? If so, what's your opinion?

Top posting. Ed said to drop him an e-mail using below. Notice the obsfucation and the clue under the address.

Ed would like a phone number and a good time to call you

snipped-for-privacy@optonline.net remove the 3 for real e-mail address

D>Howdy folks

I had a Sherline lathe and mill and a Prazi lathe clone to play with for a while. At the time I was making mostly small electronics parts from aluminum or brass, for which they worked well. They were seriously inadequate for making steel power transmission components larger than toy size.

This is my exposure to robots:

My 10" lathe and small knee mill are barely large enough to work on them, if I had to. My mill is the 1950's American original of these: had an older Enco version of it in a model shop I ran. The low quality of the small parts on it keeps me from recommending it, but it had the potential to be a good choice for a hobbyist or small shop that can't handle the weight and size of a Bridgeport. The RF-31 mill- drill I bought for another shop had more X and Y axis capacity for drilling plates accurately.

If you are making robots to teach the principles and can scale them down you might get away with a lathe and mill the size of mine or smaller. When I design a machine to do real work I have to compromise to stay within their limited capacity:

jsw

I got an e-mail from Ed with some details. Doesn't sound like they have a lot of room and it is upstairs. It also sounds like they need to spend the money quickly so I'm thinking this is a what from the "insert your favorite supply souce" would you buy to get them set up and running. Grizzly, ENCO, whatever model numbers.

### On to other things: I visited Joe and the guys at Passaic County College.

They have to spend their money by next week -- it's $7,000, may be $10,000. Maybe you can help out by asking for recommendations on the NG. They need a mill, a lathe, a drillpress and a 4x6 bandsaw, and they have a very small space, 2nd floor of a classroom building. Maybe a combination machine is the trick. They don't have a lot of machining to do -- those robots are mostly made from aluminum plate and extrusions. They're not into fighting robots.

###

Thanks,

Wes

of room and

I'm thinking

get them set

Ten grand. Now the answer is easy. Tormach.

Kevin Gallimore