Author Topic: Making Hardened shafts  (Read 3936 times)

Offline Darren

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Making Hardened shafts
« on: March 13, 2009, 01:03:45 PM »
Hi,

I'm a real newby to this so please be gentle.... :thumbup:

If I wanted to make a hardened spindle where would I start? I need to cut a taper and small spigot on the end so it needs to be machineable to do this before hardening.

I was thinking silver steel, is this ground to size? Or am I needing something else?

We are talking about 6" long and 1/2" diameter.

 :scratch:
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Offline Darren

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Re: Making Hardened shafts
« Reply #1 on: March 13, 2009, 02:21:51 PM »
Reading up a bit it seems Silver steel is a commercial low-carbon tool steel also know as Drill Rod. Sold in a semi soft state for easy machining and hardened with a simple blow torch to cherry read and quenched vertically in water. Vertical to prevent one side shrinking quicker than the other causing bending. Brine is better than water as the air bubles are smaller.

Is brine just salt water?

Another question, after hardening does it need tempering. My use has no side load just a vertical one, and it's not that great either.

It sounds easy, but is it...?

So many questions  :scratch:
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Offline sbwhart

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Re: Making Hardened shafts
« Reply #2 on: March 13, 2009, 02:30:39 PM »
Hi Darren  :wave:

Silver steal is ground to size and you can harden it, but for most home machine shop application its unusual to have to harden a shaft, silver steel is quite hard and tough, perhaps if you could tell  :borg: what you want the shaft for we could advice you if it really does need hardening, some photos may help.

If you want to harden silver steel you heat it up to cherry red its best to do this in natural light it help to judge the colour you then quench it in water, if the shaft is not to bend you need to put it into the water verticaly.

Hope this helps

Stew
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Location:- Crewe Cheshire

Offline Darren

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Re: Making Hardened shafts
« Reply #3 on: March 13, 2009, 02:38:08 PM »
Hi Stew,

I want to have a go at making a new spindle (and housing) for my record player. The spindle will rotate vertically on a 5mm ceramic ball, be held in two plain bearings and hold a 4kg platter on a taper at the top end of the spindle.

I've already made the bearings for an original spindle and housing which works very well. Big improvement. Now I want to try a longer spindle. Theory being, the longer the spindle the less play in the bearings. The remade bearing tolerances are very tight (but still spin  :ddb:) So my thinking is the next step is to move the bearings apart.
Hence a longer spindle.

Is not high loads or anything, or even fast for that matter. Only 33rpm.



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Offline sbwhart

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Re: Making Hardened shafts
« Reply #4 on: March 13, 2009, 02:42:11 PM »

Is brine just salt water?

Another question, after hardening does it need tempering. My use has no side load just a vertical one, and it's not that great either.

It sounds easy, but is it...?

So many questions  :scratch:

Brine is salt water or just plain water will both give good results with salt the steel gets less of a shock you can use oil for the same reason but you can set the house on fire  :jaw: doing this and it stinks like hell.

Tempering again it all depends what you want it for hardening will make the steel brittle tempering reduces this at the expence of some harndess  to temper again you have to watch the colour changes, they happen fast so the best way is to lay the job on a bed a sand and heat this up this slows down the rate of change, again you quench it when you get the correct colour.

It is quite easy but like everything else if its your first time it can be difficult, experiment with a bit of scrap. Its fun

Cheers

Stew

A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline sbwhart

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Re: Making Hardened shafts
« Reply #5 on: March 13, 2009, 02:45:22 PM »
Hi Darren

We seem to cross posting here  :lol:

For what you want to do I wouldn't harden the shaft it's most likely to bend slightly and I can't see any advantage

Cheers

Stew
A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline Darren

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Re: Making Hardened shafts
« Reply #6 on: March 13, 2009, 02:51:32 PM »
Thanks Stew,

So silver steel it is then, no hardening required so should be quite simple all round....

Well, I guess the taper will be the hardest bit, not having ever done one before.
I have the original spindle so copy the taper off that as per Bogs arbor tutorial recently.....darn it John...you set me off when I saw that... :ddb: :ddb: :ddb:
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Offline rleete

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Re: Making Hardened shafts
« Reply #7 on: March 13, 2009, 03:24:50 PM »
Darren, if you've cut threads before, tapers are no more difficult.  Different operation, to be sure, but no harder than facing or turning to size.

Sometimes I think us newbies scare ourselves into thinking some things are more complicated than they really are.  Once you get the mindset to just start cutting metal, you'll soon discover (at least I do) that it's no big deal.
Creating scrap, one part at a time

Offline Darren

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Re: Making Hardened shafts
« Reply #8 on: March 13, 2009, 03:57:21 PM »
Think I'll have a practice on some mild steel first, but I don't suspect too many problems. Just got to get down to it  :ddb:
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)