What material to replace compound slide please?

[Martin Shaw 1Participant @martinshaw1]

I did exactly as the OP proposes before Christmas and I got a piece of CI from M-Machine in Darlington. Excellent service and not exhorbitant for the carriage. They were by far the least expensive and it machined very nicely despite some folk telling me an 80mm face mill would destroy my milling machine, it didn't.

[petro1headParticipant @petro1head]

I would need a section 80×60

Looking at their website the only 60mm stuff is available only in 130×60

Prob put this on the back burner until I have sorted other more important things first

 

Edited By petro1head on 21/02/2023 15:31:38

Edited By petro1head on 21/02/2023 15:32:28

[samuel heywoodParticipant @samuelheywood23031]

I made something similar for my mini lathe.

At the time i didn't know of any sources for cast iron stock, so it was made from square en3 steel.

It is significantly more rigid than using the compound slide & i've not had any issues from it being steel.

However if i was doing again (& i may do that someday) i'd go with cast iron.

[HopperParticipant @hopper]

I made mine out of steel.Two blocks of 1" thick flat bar welded together one on top of the other, with a steel fourway toolpost mounted on top of that. Works a treat. And clean and easy to machine.

It is a pretty hand accessory for heavy cuts and also for general use because it does not get in the way of the tailstock.

[HopperParticipant @hopper]

I guess it was 3/4" steel flat bar welded together, not 1". Anyhow, works a treat. No vibration.

The large stud in the centre of the toolpost goes right through to a T head underneat that fits in the T slot on the cross slide. Second T bolt and nut on the foot sticking out the side. The extra two holes allow it to be hung off the back of the cross slide as a rear toolpost if needed, using two T bolts.

It has a spring loaded plunger that indexes with four holes drilled in the underside of the revolving 4-way toolpost for positive indexing.

Edited By Hopper on 22/02/2023 10:55:20

[KWILParticipant @kwil]

Posted by Dave Wootton on 21/02/2023 13:02:04:

P.S I've never worn a mask in 50 years of C.I machining, currently I must be worth something as scrap!

You must be very lucky, inhalation of fine carbon particles can inflict serious damage to your lungs leading to COPD, leading to a shorter lfe.

[vic neweyParticipant @vicnewey60017]

Posted by petro1head on 21/02/2023 14:24:49:

I have found this company which seems very reasonable for metal supply – https://www.rapidmetals.co.uk

———–

Rapid metals are very good if you just want bits and pieces as there is no minimum order, my local one in Redditch lets you wander round the offcut bins to sort out what you want.

On saying that I recently wanted some 300mm X 2" aluminium round bar and I got it £4 cheaper off Ebay inc the post!

[Ex contributorParticipant @mgnbuk]

You must be very lucky, inhalation of fine carbon particles can inflict serious damage to your lungs leading to COPD, leading to a shorter lfe.

Never saw anyone wear a mask when machining CI anywhere that I worked. The machine shop at Broadbents was covered in fine CI dust & one of my holiday shutdown jobs was to clean all the fluorescent lamp fittings for accumulations of talcum-powder fine CI dust. No special protection advised or provided for what was a filthy job & no long term ill effects.

The last 16+ years I worked in a graphite machine shop. While there was dust extraction, there was still fine graphite dust pretty well everywhere. Dirty hankerchiefs normal & you got grubby, but no long term effects. My employer had had an HSE inspection where they took dust samples & did extensive tests, but came back with no special recommendations as they found no special health hazards, explosion risks etc.

I don't belive that it is good to breath fine dusts of any persuasion, but have not seen anywhere that CI dust poses a particularly serious risk ?

Nigel B.

[DiogenesIIParticipant @diogenesii]

Posted by samuel heywood on 22/02/2023 00:28:10:

However if i was doing again (& i may do that someday) i'd go with cast iron.

Just interested as to why?

[SillyOldDufferModerator @sillyoldduffer]

Posted by DiogenesII on 22/02/2023 17:30:23:

Posted by samuel heywood on 22/02/2023 00:28:10:

However if i was doing again (& i may do that someday) i'd go with cast iron.

Just interested as to why?

Cast Iron tends to absorb vibration, making it a bit easier to get a good finish. No so useful, cast-iron is brittle and weak in tension, so T slots get broken. Otherwise, cast-iron is a better choice than steel, and cheaper if you own a foundry.

On the other hand, cast-iron is useless for making bells. Doesn't ring and soon cracks.

I'm not sure what's the best possible, money no object, metal for a saddle. Gold,Lead and Copper are too soft, whilst Silver, Brass and Bronze all ring, Solid Tungsten perhaps. Any other suggestions?

Dave

[Martin Johnson 1Participant @martinjohnson1]

Posted by Neil Wyatt on 21/02/2023 11:43:26:

Meehanite, a form of cast iron that is less brittle.

As above, wear a face mask or it will turn your snot black for a week.

Neil

Edited By Neil Wyatt on 21/02/2023 11:43:43

Meehanite is a corporation that licenses participating foundries to produce a variety of cast products. What is usually referred to as Meehanite is continuous cast bar – excellent quality, no hard spots but CAST IRON. What confuses the issue is Meehanite also specialise in SNG and high nickel irons with a whole range of applications from crankshafts to ultra wear resisting. Unless you specify a particular grade Meehanite means absolutely nothing.

Martin

[Neil WyattModerator @neilwyatt]

Posted by Martin Johnson 1 on 23/02/2023 12:45:13:

Posted by Neil Wyatt on 21/02/2023 11:43:26:

Meehanite, a form of cast iron that is less brittle.

As above, wear a face mask or it will turn your snot black for a week.

Neil

Edited By Neil Wyatt on 21/02/2023 11:43:43

Meehanite is a corporation that licenses participating foundries to produce a variety of cast products. What is usually referred to as Meehanite is continuous cast bar – excellent quality, no hard spots but CAST IRON. What confuses the issue is Meehanite also specialise in SNG and high nickel irons with a whole range of applications from crankshafts to ultra wear resisting. Unless you specify a particular grade Meehanite means absolutely nothing.

Martin

True enough, but I did specifically order Meehanite for the t-slotted table in the picture. If you order Meehanite from one of 'our' suppliers, you will get a continuous cast iron suitable for machine tools.

http://www.model-engineer.co.uk/news/article/don%27t-do-this-at-home–a-t-slotted-slide-for-a-mini-lathe/20622

Also:

meehanite

[Martin Johnson 1Participant @martinjohnson1]

I think you miss my point, Neil. Continuous cast iron bar is cast iron. It is not "less brittle". The data sheet in your second link shows a tensile of 250 which is a good quality iron, but still cast iron. Typical foundry fodder would be around 170.

The reference in your blog to heat treatment for a prolonged period fell out of use a long time ago. True you can get over hard spots to some degree with heat treat, but you wont improve ductility. For that you need SNG.

Martin

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