How difficult is it to setup a screw machine - I mean a machine not me

I'm not thinking about a davenport or something with cams. I'm thinking more along the lines of Cincom and Citizens etc. Kind of in the 20mm class.

We buy a lot of Stainless Steel fasteners now (approx 6K yr which is a lot to me) and I can see advantage in making my own stuff like 3/8-16 S.H.C.P. and Shoulder Bolts and some of our shaft work which ranges to 13".

It would be nice to bring that in house as well as maybe do some outside work. So having never run one, whats the up side and down side? I have seen some You Tube videos and the ones on broaching. I don't want to get into medical stuff (crowded field) mainly just my own stuff.

Do they do synchronized hand off to sub spindles?

Frank S. in Tennessee

This might be a trend. Maybe I should make High Heels?

Make your own commodity fasteners?

Shirely you jest?


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Think Snow Eh!
Ox

I was thinking exactly what OX said. I'd stay with off the shelf fasteners, unless you have a specific design that is not offered on the open market. There's very, very, little margin for profit on standard fasteners.
High heels? Hmmm.... I'll have to ponder that one.

"Do they do synchronized hand off to sub spindles?"

Yes, If I understand correctly what you are asking, you can sync. the two. I used to do that (long ago....) but there was sometimes a problem with the sub not staying in sync and it would alarm out, so I took out the sync code. But it has been a while.

Must be something with Spike Heel adverts lately.
Did anyone notice the Q-Mark adds lately?

I wish I could find a pic on the web

Page 105 in the month's CNC-West.

It depends on the market, the price you currently pay, and how much you want to spend on a machine. Most commercial fasteners are rolled threads....stronger than a cut thread and extremely economical in large quantity. If your screws have a commion wrench size, all the same material, etc, it may pay to set up a swiss, but chances are it would be a cost increase. Swiss stuff generally is not cheap. 13 inches would be an awful long part for a swiss as well. They are not overly difficult to set up, live tools adds complexty, and swiss is ass backwards from " normal turning centers" on some things.

Well we use 3/8-16 X 1.25 S.H.C.S. a lot as well as 3/8-16 X 1.0 and buy them by the hundreds if not thousands and then they go and get Black Oxided. But there is one fastener where the head is too large 1/2 X .750 Stripper bolt and we are paying 2.15 ea for those and buy several hundred at a time (400 - 600). On a new design of our product we are running out of room to have the head of the bolt hanging in the air. I have been thinking of setting up the Turret Lathe and trimming and contouring the head with a nice radius to make it less obtrusive.

This is a shot of a standard Stripper Bolt we use.


This is a shot from an angle and it really needs a better solution. I have thought about getting shorter bolts and turning down the head so it slips into the frame.


This shot shows how little meat there is for counter boring the head or doing other treatments.


This is another perspective


Besides this we do small shafts and with the right machine I can setup for new product. I have been wanting to do some shafts with a 3/4-20 thread which would allow a larger loading per thread due to increased surface area.

Having my own Swiss screw machine I think would be of benefit. Besides its one more thing made in the USA not India or Malaysia or wherever Best gets their screws.

Hey ARB, I saw that. In fact got my CNC WEST (which is getting to be a really nice read) and my MTW. Don't forget the Sheffield babe on pg 80 and she needs some nice heels too. There is an old saying that sex sells and certainly if you want me to look at your ad for more than the 3.4 sec. average time - better be some leg in there and not some dudes. I thought the Q-Mark was pretty neat.

Frank S. in Tennessee

May be a hell of a lot cheaper to re- design the part so you can use standard fasteners no?

Even if it took a 2 months it would be cheaper than a citizen screw machine.

Dave

Dave

Well we have just gone through a painful redesign process and re-profiled the Side Frames to get a workable solution. For this batch it will have to do, but I need to revisit it in the near future. We are constantly redesigning, but we also have some set in stone dimensions that we can't screw with so our products are backward compatible if someone wants to update their product. We can't keep changing parts drastically as we end up with unusable excess on the shelf.

One of the pitfalls of being the designer, engineer, machinist, packager, shipper, and janitor.

Frank S. in Tennessee

Frank, with those low volumes you could easily run them on a small cnc lathe...throw in a bar every hour and let it rip. Even with making them yourself, there's a good chance that your cost will increase - many times the material will cost you more than the off the shelf hardware...at least with commodity items.

But...if you really just want to have made in USA stuff, there are still manufacturers around making SCHS and stripper bolts domestically. The real commodity stuff (ie. 3/8-16 x 1.0 HHCS) is pretty much all imported - may even be hard to find domestic, unless you call out a mil spec.

Is there other items that you could use the lathe for...I recall you said something quite a while back about late parts from your lathe guy??? If you had the lathe at your disposal, could you design other complimentary products that the lack of a cnc lathe has made a barrier to entry for you?

Steve

Even though a typical 18-8 SS screw is weak as mud, its still far superior to a lathe made one. As mentioned already, the rolled threads give much better strength than cut threads. Also, the heading process that forms the head of the fastener produces grain flow patterns that are much more desirable and durable than bar stock necked to the shank diameter in a lathe.

If you were making fasteners and selling them as a part of your assembly, you might get by. But if you offered any sort of replacement fasteners to your customers, you could be in violation of the federal fastener quality standards act unless you added a disclaimer clearly stating that your fasteners don't meet common industry accepted standards for the type fastener you're selling.

Seems to me like going wide open backward to spend at least 5X the money on a fastener, only to have to state that its inferior to the one that costs 1/5 as much.

I say 5X as much because I buy 1/4-20 x 1 18-8 SHCS for about a dime apiece in quantities of a few hundred, and a man would have to be nuts to furnish the material and make them for 50 cents apiece by normal machining methods.

Having my own Swiss screw machine I think would be of benefit. Besides its one more thing made in the USA not India or Malaysia or wherever Best gets their screws.

Click to expand...

So buy your screws from someone that sells USA bolts eh? Like Holochrome? Made in USA!

That Citizen however is NOT! (Not that you really care either way tho.)


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Think Snow Eh!
Ox

13 inches is long for a swiss, but not if the part allows for multiple pulls. Depends on the part geometry.

Hell Mitty change the design all around, "NEW AND IMPROVED" give the customer an excuse to get a new updated, state of the art, cutting edge toy with off the shelf fasteners.

Dave

Dave

The fasteners are off the shelf. Change ain't coming, maybe reform but not change. If I could find some button head stripper bolts that would be the ticket.

I'm also trying to find a better way to make the stuff we need, all the little trinket stuff. We always improve, but I don't want to sound like a Tide Commercial "New and Improved in a more convenient size". That's slippery speak for we made it smaller and charge you more.

Frank S. in Tennessee

Have you noticed that the push for CNG shows that there are very few "filling stations" and the cost of PHILL (the home base filling unit) is not posted, much less a list of cars and trucks already manufactured - other than Honda

You can certainly make them yourself on such a machine, but be aware that the broaching of hexes much bigger them 5 or 6mm might be troublesome. Stock might push back in the guide bushing. The threads themselves can also be an issue.

Those off-the-shelf ones you've been buying are probably blanked out on and older cam-driven or mutli-spindle screw machine, then have the thread rolled with flat dies. On a CNC sliding headstock (Swiss-type) lathe, you would have to choose between a 3-roll die (Fette) or single-point threading. The rolling will give you a stronger thread, single-point will give you a nicer-looking one with easier-to-control diameters.

Many sliding headstock machines wouldn't have the torque needed for the thread rolling, the broaching, or both. Shop carefully! And yes, BTW, most now have pick-off spindles.

mitty38382 said:

Don't forget the Sheffield babe on pg 80 and she needs some nice heels too.

Click to expand...

Yeah I caught that one too

"That's slippery speak for we made it smaller and charge you more."


That's what I'm talkin' about, green money man. High heels and silk panties all around.



Dave

Setup on a citizen isn't too bad. I picked up on it in about two weeks, doing a little work with live tools and such. I was able to modify programs and do a little fancy live tool work, but not quite able to program from scratch.

I've seen Mitsubishi and Fanuc Citizen controls and they were both very user friendly. Nothing like regular Fanuc. They're made to be setup quickly, very task oriented. Dropping a part in the parts catcher is one M-code, for example.

On the other hand, there is really a ton of stuff going on. It would be a real struggle without an experienced Swiss setup guy to work through the problems.

The thing that amazed me about Swiss machines is how rock solid they are. You can run about .0002" total tolerance on 1/2" length all friggin day long, turn it off and start it up the next day and still be within .0002" without a warm up, let's say in brass, where you don't have much tool wear.

Spending 150g's on a machine to make 5K a year in parts...bad math.

Once we start getting into high quanitities with fasteners, I opt to stay away from the industrial warehouses and go to Bolt Specialty houses. They have the contacts to have the fasteners made to your spec and save you some coin and time. They also will have all the standard items in bulk, kind of the Costco of the industry.

You can give these guys a try, they have done well for me:

Shallcross Bolt Specialties- 1.908.925.4700 ( I deal with Mike )