Hi guys.
I know a lot of you have used threaded rods, as a substitute for leadscrews. But has anyone tried to use stainles steel rods, and then polishing it for a smoother finnish. And then using either an delrin or nylon nut, for the axis movement. I would think that when polished, everything would run real smooth.

Regds

Max

Sir,

Here is a source of acme threaded rod AND nuts.

Green Bay Mfg. Co., Box566, Two Rivers, WI 54241-0056, Ph 920-793-2411
I have not used them but they have consideraable variety.

Regards,
Jack C.

Normal threaded rod actually works quite well for leadscrews.

Its primary failings are twofold...
First is surface finish which can be dealt with by polishing, or buying unplated rod.
Second is thread accuracy. Since it's not designed for precision applications, it's not made precisely.

There's actually a 3rd failing, too...the thread does not transmit power as efficiently as ACME or ballscrews. But, for small homebuilt routers, this is not so big a problem as it would seem.

Threaded rod also has some major strengths, like being cheap and available EVERYWHERE. It's also pretty darned good in quality, despite the occasional thread wander. I'm retrofitting a Chinese mill-vise, and replacing the absolutely horrid leadscrews with threaded rod. It's an "on the cheap" retrofit, and the threaded rods should be quite adequate.

-- Chuck Knight

Max-DK.....hmmmmm....you're going to polish a threaded rod.....boy that will be a labor of love.....sure it will work great....snicker...snicker......

Actually I have been making and selling 3/8-16 & Acme 1/2-10 rolled thread leadscrews with delrin nuts on eBay for months now!
http://search.ebay.com/_W0QQsassZeaaenterprisesQQhtZ-1

The problem with rolled threads is the metal flakes which get pressed flat while the metal is in the rolling process! The 316-stainless alloy is the best thread, as it forms better without flakes like steel! I have been buying bulk All-Thread from several places, looking for the straightest and cleanest threads!

After turning the ends, I occasionally run a piece of ScothhBright over the threads to remove the scales! But polishing is not necessary! You can also buy a "Machined thread" which is not rolled! Much higher price tho!

If you need smooth travel, NOOK rolled ball screws go for $1.25/inch +$25.00 for the ball nut. Turning the hardened ends is a bit tricky !
http://www.homeshopcnc.com/page2.html

Eric

Thanks for the inputs. The reason i was asking, is that the Acme rods are not available here in Denmark. So i think i'm going for a standard threaded rod 14mm, as this will give me a resolution of 0,01mm/step. For my first machine this will be ok, later maybe real leadscrews.

Standard threaded rod should work fine for a first machine. If you did want a better rod, you might try looking for Trapezoidal screws rather than Acme. Trapezoidal rods are designed for power transmission just like acme, but but have a slightly different profile, and use metric sizes, so might be available in Denmark. Here is som information about trapezoidal screws. http://www.roton.com/index.php?section=82&print_code=9

I have used stainless steel threaded rod as well as the standard one on my machine and the only difference I have seen between them is that the ss version is stronger, therefore it does not whip as easily as the standard version. There should be no need to polish ss threaded rod it as it comes with a very good finish already.

Jason

Thanks for the inputs. The reason i was asking, is that the Acme rods are not available here in Denmark. So i think i'm going for a standard threaded rod 14mm, as this will give me a resolution of 0,01mm/step. For my first machine this will be ok, later maybe real leadscrews.


Hello Max,

jeffs555 is spot-on. DIN 103 trapezoidal spindles are available in Europe.

They are very nearly the same as ACME, but come in metric diameters. I have been agonising about whether to use DIN 103 or ACME. The problem in the UK is that although DIN 103 spindles are quite inexpensive (pitch accuracy 0.15mm per 300mm), I don't seem able to find simple nuts for shaft fixing etc. Anyway, a company in the UK called Huco have the stuff. Here is a list of their outlets in Denmark....

http://www.huco.com/distributors.asp

If you go ahead and find some cheap nuts to suit, I'd be really grateful if you could let me know.

Good luck

Martin

Martin, you mean these nuts?
http://www.skf.com/portal/skf/home/products?paf_dm=shared&maincatalogue=1&lang=en&newlink=1_16_21
Carel

Martin, you mean these nuts?
http://www.skf.com/portal/skf/home/products?paf_dm=shared&maincatalogue=1&lang=en&newlink=1_16_21
Carel


Hello,

Thanks

I'm just looking for absolutely straightforward hex nuts like a normal M12 nut but with a DIN103 trapexoidal thread. The backlash can be enormous, I don't care.

Regards

Martin

(sorry, I have to go home, I'll be back tomorrow)

Martin, they are on the Duco Site you referred to:
http://www.huco.com/products.asp?p=true&cat=390
Or still more unobtainnuttable?
Carel

Martin, they are on the Duco Site you referred to:
http://www.huco.com/products.asp?p=true&cat=390
Or still more unobtainnuttable?
Carel


Dear Carel,

Thanks for pointing me in the right direction. I'll find out how much they cost tomorrow and let you know.

Best wishes

Martin

Dear Carel,

Thanks for pointing me in the right direction. I'll find out how much they cost tomorrow and let you know.



Hello Carel,

Not good news I'm afraid to say.

Each 12mm steel nut costs 3.40 UK pounds. Each 14mm one costs 4.30 UK pounds. Then add the tax. If you are making a three axis machine and you need 4 nuts per axis to lock the screws on to the thrust bearing inner races, you a going to have to spend about 50 to 60 UK pounds for a dozen nuts.

You can get 1/2"-10 Acme nuts for 99 cents in the US. That's why acme looks pretty attractive.

Regards

Martin

Industrial parts don't come cheap. Normally they look puzzled if you ask how much a part cost. On the other hand you have to ask (if you have a lathe), what the cost of raw material plus labour is to produce this. Then 4 pounds can be cheap. Look if you can optimize your design by eliminating the nuts. A bearing locked by nuts on a threaded rod is not optimal. If you machine the ends, you don't need the nuts.

Carel.

Hello Carel,

I know that nuts are not ideal in this application but they have the virtue of simplicity. I do not have a lathe. Getting a comercial workshop to machine the ends would be eye-wateringly expensive. I'm going to find out how much the shipping costs would be for acme spindles and nuts sourced from the US.

Thanks for your help.

Best wishes

Martin

What happened to England, the founder of the industrial age? Not a lathe in sight and only available at exotic rates? Flying in parts from the USA, where your ancestors went? England: make the lathe and mill again a domestic appliance as it was and put yourself on the map again! ;)

Carel

What happened to England, the founder of the industrial age?


Hello Carel,

Part of the answer to that question is that we now live in rip-off Europe and have a monstrous shambling crew of Brussels criminals to support...

Shall I go on?

Best wishes

Martin