Aluminium as a feed nut

[Piero FranchiParticipant @pierofranchi37209]

Just wondering why not use aluminum as a feed nut??

Was going to try and make my first ever feed nut, its for my Clarkson tool and cutter grinder.

I will probably mess it up anyway and will take a few attempts at it to get it right.

but I do know with a lot of cylinder heads (on cars) the cams run straight through the aluminum cast head, no bearing shells,

thats steel (cast normally) to aluminium so why not my feed nut ????

[Piero FranchiParticipant @pierofranchi37209]

as title

[MWParticipant @mw27036]

What type of aluminium are we talking about here? Pure Alu is way too soft.

It normally has to be an alloy or temper to get it hard enough.

Michael W

[John ReeseParticipant @johnreese12848]

I don't think it will last long. Bronze is the traditional material.

[Piero FranchiParticipant @pierofranchi37209]

I dont have any bronze

[duncan webster 1Participant @duncanwebster1]

Friend of mine used Delrin for the nut on a milling machine feedscrew. Much more heavily loaded than a cutter grinder I think. Just because bronze is traditional doesn't meen other materials won't work.

Old Triumph motorcycles had the big end running direct on the ally con rod, they lasted for years.

[John RuddParticipant @johnrudd16576]

Cast iron?

[Piero FranchiParticipant @pierofranchi37209]

My lead screw nut was very very worn and the work would some times be pulled into the grinding wheel.

I have now retro fitted a gib locking bolt that will lock the inward moment on the grinder

as the table is apart, i quite fancied trying my hand at a new leadscrew nut

[Mike PooleParticipant @mikepoole82104]

I would not think any aluminium would make a good nut but at the risk of wasting your time making one and having it wear out quickly it could be a good practice for making one in bronze.

Mike

[Andrew TinsleyParticipant @andrewtinsley63637]

The generic 920 lathes seem to all have aluminium nuts on the cross slide. At least the ones I have seen, have them.

They do wear out, but it takes a lot longer than you would expect. I have done a replacement on a friends lathe and that was using bronze. If I am going to the trouble of making a well fitting nut, I would prefer that it lasted, so I don't have to do the job twice!

Andrew.

[alan-lloydParticipant @alan-lloyd]

White metal lined on the Triumph con rods

[Piero FranchiParticipant @pierofranchi37209]

As I only have aluminium, I think ill try it if only as a test to Polish up on the skills needed to do the job latter on in brass/bronze

which of the two would be better. brass or bronze ???

[Sam Longley 1Participant @samlongley1]

Oilon plastic or Tufnol whale. Both cheap enough for some experiments & failures during manufacture.

[Piero FranchiParticipant @pierofranchi37209]

I have much thanks to give some one from this forum (cant find/remember his details) for all my metal. much of which is aluminum.

 

there was this guy from Southampton giving away what he considered scrap

to me it was gold!!!!

 

so I have some to play with (aluminum) thanks to this kind gentleman

Edited By Piero Franchi on 30/12/2017 19:14:28

[not done it yetParticipant @notdoneityet]

Delrin (acetal) melted and squeezed makes a feed screw nut with virtually no backlash when made (I needed to relieve the thread a little to make it less tight for use). Working as a cross slide feed nut, with better results than the worn out brass item, even though a bit tighter in operation thus far.

Raglan used the die cast lead screw half nuts from the American equivalent. They work OK.

A tool grinder can do without any, or much backlash. I try to never rely on a lead screw nut to prevent backlash. Tightening gibs on anything but the direction of cut makes things much more rigid.

[BazyleParticipant @bazyle]

I think it is worth trying the aluminium as the grinder has a tenth the use of a lathe so it will still last a fair time and you will gain experience.

[Michael Cox 1Participant @michaelcox1]

I have a Delrin nut on my lathe cross-slide. I did the mod some months ago and the backlash is still zero, see:

http://mikesworkshop.weebly.com/tee-slot-cross-slide.html

The part dealing with the Delrin feed nut is at the end of the page.

Mike

[Phil WhitleyParticipant @philwhitley94135]

aluminium bronze, or Duralumin should do the job, and anyway as all have said, it is good practice. the only thing you have to watch for is wear in the middle, or the most used area of the screw thread, then it will be fine at the ends, and slack in the middle. The cross slide thread on my original lathe, a DS&G 13z was beyond the pale, and I couldn't do it, because with it out, I didn't have a lathe! Took it to a local engineering shop, and they cut off the fancy splined end, bored it and fitted a new piece of acme thread into the bore, secured with a roll pin, job done!

[John HaineParticipant @johnhaine32865]

The standard feed nut on the ML7 cross-slide uses Mazak I believe! So why not try ali? If/when it wears you can always make another. How big is it? I have some (I think) 25mm bronze bar if you'd like an inch or two after practicing on the ali.

[Nick HulmeParticipant @nickhulme30114]

Where Aluminium is used against steel there is often significant wear to the steel.

[Mark RandParticipant @markrand96270]

Aluminium nut with a grinder has the risk of picking up wheel grit and abrading the screw. Bronze is a poor choice unless the screw is hardened and there is copious lubrication (The reason that Bridgeports wreck their feedscrews). Brass will wear quickly.

Acetal is simple to machine and can cope with limited/no lubrication. Cast iron is simple to machine and will wear in preference to the screw. Also more tolerant of limited lubrication.

Edited By Mark Rand on 30/12/2017 23:06:34

[Jeff DaymanParticipant @jeffdayman43397]

In the automotive applications the OP mentioned, shafts are run directly in aluminum heads. This practice was also done (and maybe still is) in motorcycles.

The reason it works OK is that a high silicon aluminum die casting alloy, sometimes with some small % of copper added, is used.

I have never found bar stock of this alloy for sale, but if you could find some, or reclaim some from a broken car cylinder head that had direct running shaft in it, it may work.

However given the leadscrew wear you mentioned I think ANY nut material for a new nut may not work as well as is needed. You may be wise to replace the screw also.

[Nick HulmeParticipant @nickhulme30114]

Posted by Jeff Dayman on 30/12/2017 23:20:40:

In the automotive applications the OP mentioned, shafts are run directly in aluminum heads. This practice was also done (and maybe still is) in motorcycles.

Hydrodynamic bearings are a very different application to a feed screw and nut, suitability of materials in one does not suggest suitability in the other.

[HopperParticipant @hopper]

Posted by Piero Franchi on 30/12/2017 19:00:28:

As I only have aluminium, I think ill try it if only as a test to Polish up on the skills needed to do the job latter on in brass/bronze

which of the two would be better. brass or bronze ???

I used brass for the new half nut on my M-Type Drummond Flagellator some years back and it works perfectly. Easier to machine than bronze and less wear on the much more valuable lead screw. That's why some manufacturers such as Myford and South Bend use Mazak for half nuts. (alloy of zinc and aluminium), apart from being cheap, it wears out rather than the leadscrew and can be replaced more cheaply.

[Raymond AndersonParticipant @raymondanderson34407]

Oilon or Nylon 66 would be suitable, although if it were me then I would be using Cast Iron or Phosphor bronze. Each to his own.

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