Cheapish screw machine to make one part forever.

Hello.
I need advice on getting the cheapest machine to make one part out of 6061 for all its life. Its our product and so far we are outsourcing it. If volume picks up we would like to bring it eventually inhouse. There is not much tolerance and it would be great to do it by ourselves rather than paying someone else to do it. Please take a look at the photo.

Thank you.

IMO, if you got the machine for free, and just had to pay for rigging it in and having it wired, plus tooling, you'd spend more than a variety of places would charge you for a lifetime supply of the things. What kind of volume are we talking?

Assuming that’s a grid on a cutting matt or similar not a industrial grating and the part is small as in sirca 1" long. A easier option than screw machine might be a small gang tooled lathe with a bar feeder, there a lot easier to setup and adjust for size than the old mechanical only screw machines. Equally you can run water based coolants so a lot less mess and part clean up agro.

Add a high speed spindle option and splash the cash on a full set of diamond tipped inserted cutting tools and it should be about as low maintenance and productive as you wish with finishes that are things of beauty. Decent material and a large enough capacity bar feed it should be more than possible to have it run over night once you get it settled in. If the parts really that small and running lights out makes mostly scrap the odd night it still would not be much loss.

That all said, your easily 10+K or more to set-up to make them, like the above posters you could buy a lot of them for that kinda outlay. Once tooled up and running though your per part cost should be in the single digits and set-up properly should only need a passing check a few times a day by some one.

Cubic Machinery

I would check with these guys before buying a machine, tooling, training an operator or two. They have all sorts of Swiss screw machines. Screw Machine Products & Services - CNC Screw & Swiss Machine Parts - San Antonio, TX | Cox Manufacturing Company

"one part forever" does not exist without some definition of speed, volume, accuracy needed // desired.

I no-quoted many hopeful clients who wanted cnc machines/lathe to make e. 20k parts per week (lathe) for sub 0.5€ each in steels.
Cannot be done.

The OP premise of cheap screw machine to make cheap parts or one part in qty -- does not exist.
Any old-school screw machine expert could buy, set up, tool, a machine to make one specific part.
But the old-school experts are not free -- even if the basic machines are very low cost now after end-of-life, mostly.
And they will need either very expensive custom tooling with many iterations from modern providers ..
or many trials of shop built tooling at a large nr of hours at $$.

There are guys on this board who could do that -- for themselves -- and have about 0.02 $ production costs, marginal, plus material & ancillaries.
One can learn how.

The business minimax for *You* would be to pay about 20.000$ for someone on this board to teach You how to do it, in 2-3 weeks.
And then spend the same on fiddly bits and trials, until you can actually make the right tooling/cams/decisions.

The base case is about 100k$ in start-up costs to make anything well in quantity, at low marginal costs per part.
If you are going to make 200.000 units, the base is == 0.50$ per part in sunk costs.

hanermo said:

And then spend the same on fiddly bits and trials, until you can actually make the right tooling/cams/decisions.

The base case is about 100k$ in start-up costs to make anything well in quantity, at low marginal costs per part.
If you are going to make 200.000 units, the base is == 0.50$ per part in sunk costs.

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That's BS, there's a few people I know knocking production parts out on $1-4K Hardinge HNC/CHNC's, a Mori SL1 in great shape sold with barfeeder last year for $1250. That machine was banging out high tolerance parts before the auction, and still is for the new owner.

With a little imagination max machine cost with barfeeder is $5-10k

IMHO opinion, the man to listen to would be PMer ''Camscan'' ..he's spent a life time camming up and tooling cam autos ( screw machines) so can advise on both the technical and financial aspects.

I don't think the above poster understand the current situation here in the USA.

"Brownies" are $2k-$5k tooled.

I was in a re-build shop that has a warehouse with W&S multipsindles (there's
a niche market eh ?) That will re-build on contract, and fully tool
to make your part.

As the machine is "Bathtub shaped" and does not need a fancy foundation,
he routinely tools up for customers, and ships them via truck.

He had one when I was there, they wanted a change to a different part.

Yup, unwired it, put it on a truck, shipped it across the country to his shop.

Where he re-tooled it, and ran it off to make the customers spec.

Thence back to the customer via truck.

digger doug said:

I don't think the above poster understand the current situation here in the USA.

"Brownies" are $2k-$5k tooled.

I was in a re-build shop that has a warehouse with W&S multipsindles (there's
a niche market eh ?) That will re-build on contract, and fully tool
to make your part.

As the machine is "Bathtub shaped" and does not need a fancy foundation,
he routinely tools up for customers, and ships them via truck.

He had one when I was there, they wanted a change to a different part.

Yup, unwired it, put it on a truck, shipped it across the country to his shop.

Where he re-tooled it, and ran it off to make the customers spec.

Thence back to the customer via truck.

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That was the idea. I saw a screwshop that was closing and selling and had a tonne of tornos cam machines. I thought if I could get one similar and set it up that should not be too expensive.

There are a couple of Citizen Cincom machines on ebay right now for $4,000 or less, depending on capacity. They're old, circa 1990's, but we run a F20 almost daily on small aluminum and stainless parts. It isn't a 'fast' machine as far as inches per minute go, but it'll hold tenths all week long in aluminum. And since they're CNC, if you ever needed to make a rev in your part (don't say it can't happen...) it could be easily re-programmed

plutoniumsalmon said:

That was the idea. I saw a screwshop that was closing and selling and had a tonne of tornos cam machines. I thought if I could get one similar and set it up that should not be too expensive.

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Get a couple of them.....then while one is running, you have plenty of time
to set up the other ones....Where is JRIowa ?

As the late Mark McGrath proclaimed on several occasions, .when you switch on a cam auto or turret lathe you can be pretty sure it will start and run,.....a CNC - especially the older machines, not so.

Question -- can "Brownies" and/or gang-tooled lathes carry live tools that can mill the flats that OP's part has? Or are there other tricks with which to mill flats?

My first thought was to just bring in a basic Swiss machine with barfeeder and get on with it.

Regards.

Mike

This would be a great job for an old Davenport.

Hi guys,

Long time lurker, first time poster, so go easy. I believe I can add something here.
My screw machining experience is limited to swiss cnc and swiss cam autos, so I can't speak for the capabilities of a Davenport or a B&S.

The only "swiss cam auto" way I know to get those flats on that part is with a very particular machine arrangement. A Strohm Sj125 hydraulic index stop spindle with a split rocker and "X & Y" axis end milling unit in the T1 position. As luck would have it, I have one in storage, waiting for a new lease on life. I got it with some Tornos I wanted, and never had a use for a stop spindle. Since your on the other coast with shipping being more than the machine is worth. I can run this job for you cheap if the quantities and part life justify the hassle of designing cams/setting it up, or maybe sell it to you as a turnkey. I don't believe the cycle time will be very competitive to a cnc, I can do a rough layout with a drawing, but if I had to guess probably 35 to 40 seconds. The job needs to be done in 360 degrees no other ways about it. PM me if interested.

I sold three brownies with bar feed along with 3 55gal drums full of tooling, spare parts and cams all for the tidy sum of $250.00 on Ebay. They picked up the shipping, I placed on truck for them.


So...yes machines can be had inexpensive, tooling can be had inexpensive.

If a machine NEEDs something you cannot buy cheap, parts CAN be very expensive. Tooling CAN be very expensive when you NEED something.

Cams are needed to run jobs...I quickly learned to optimize machine time you NEED the right CAM to be made for the job. I also learned if your pretty savy with machines you can Pick through your arsenal of Cams and find one that will sorta kinda work...sometimes a little mill here, weld there will fine tune a cam to work even better. Thats where experience comes in.

A good, experienced screw machine guy can usually trouble shoot a broken, jammed machine in short time and get her up and running.

That said...try to find a Good Screw Machine guy...the ones that are just ok, they can turn a running machine into a not running in short time. They can untweak a beautiful running job to one producing scrap in seconds, they can jam up a machine in no time.

Me, I saw the machines had a place, they made good parts very very quickly in the right hands. I also saw they needed the right hands.
Issue for me was twofold, most of the parts I need to make...Good was not good enough so into the CNC they went. And the second part, I was not the Screw machine guru and the guy who was didn't really want to work when he didn't want to work. So after another no show week I placed machine on ebay, when he came in the following week everything screw machine related was gone.
I may have only got $250 for everything...but the look I got was priceless.

Anyway, for your own part, what I see you can make pretty quick on a Cam machine. But machines do need some attention and if your familiar with them, repairs can be quick. If your not there lots of multi-movements that happen at one time and it can take some time to figure out.
I have a customer that bought, setsup and runs his own Brownie. Learned a good amount of it on his own, some he learned from guys he hired. It was a long learning curve, but he makes good parts at good prices. So it can be done.

digger doug said:

Get a couple of them.....then while one is running, you have plenty of time
to set up the other ones....Where is JRIowa ?

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As much as I hate the old prick. This isn't his bailiwick. He does Nuclear qualitative valves. General Repetition would just bore him.

this is gang lathe all the way. look at a gt27 with a magazine barfeeder. would basically run forever.

SDConcepts said:

this is gang lathe all the way. look at a gt27 with a magazine barfeeder. would basically run forever.

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How do you make the flats with a gang lathe? Are there live tools for something like the GT27?

Regards.

Mike

Finegrain said:

Are there live tools for something like the GT27?

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Yeah. Two flavors that I know of. One is basically a Foredom handpiece in a gang toolblock, driven by a shaft from a slightly-distance motor. The other is a light-duty version of a typical turret live tool. Both types would be fine for aluminum or brass. I would not expect to mill a lot of steel with them.