Finishing Steel

Hiya

I have recieved some 230M07 Steel to build a Harold Hall Tool Rest.

I am a little disapointed in the colour of the steel. It isn't black like cast iron but I wouldn't call it particularly bright either.

I look at the Rest done by Wolfie in this thread and it looks a lot more like the pictures in H's book that I am imagining mine will be.

So what is the secret guys ??

If you want shiny, polish it up same with all metals.

Thanks but what with.

Spit polish and elbow grease ! LOL

When I served my apprenticeship at the then British Steel Works (BSC Redcar), we were given lumps of black steel bar and told to make a drill angle grinding gauge - as per supplied drawings. They had to gleam like chrome.

I spent hours polishing this lump of rotten crappy metal with various grades of wet-n-dry, wire wool and polishing compounds until the required surface finish was achieved.

Now I would remove the worst with a file wet-n-dry and then put it on the buffing wheel, same end result.

I still use the same gauge today and it still has a reasonable finish, the effort put in all those (30+) years ago paid off, the surface is still in very good condition.

CB

Ah yes, buffing wheel sounds like a good idea, do you use anything on it maybe ?

Chris, Wolfies grinding rest was machined and I can see he has not surface finished it to remove machining marks !

Now, you say your steel isnt black like cast iron, but not bright either. To give a bright surface you need to dress the surface with a file at first and then get some chalk and rub it into the file teeth and it will cut finer and give you a good surface. You will be able to remove even the file marks !

If you need to go further, then get some 'Wet and Dry' paper, grade 150, and a block of wood that is flat and wrap the paper around the block and get polishing, if you want a further finer surface then get some bees wax and rub that onto the paper and it will give a superior finish.

Other than that you will have to surface grind the metal !

Let us know how you get on.

Clive

Brilliant - Thanks

Once the surface scale is removed, try Garryflex blocks. Work down from the roughest to finest.

3 blocks at about £3 each (from Amazon or Fleabay) will last for years. Quick and easy to produce a satin finish. They won't remove deep machining marks though.

Thanks Guys

You need to learn how to draw file first with fine files used sideways along teh work and then wrap the file in emery cloth and use the same motion.

Personally I would not use a buffing wheel on any form of tooling as they have a tendancy to round over edges and could result in convex surfaces. In fact I hardly ever buff a part unless I want a polished shiny surface.

J

I've struggled with this a bit too like Clive says in fact its not really polished up at all. I was having a spot of trouble with my milling machine at that time and the blunt cutteres made quite a mess.

I have a coarse and a fine file and two or three grades of emery. My problem is that when I attack things with a file to get the worst marks out I aend up with curved edges because with the best will in the world I seem unable to file dead straight (I also struggle to saw straight - some kind of technique failure?)

I've had some good results with pieces that can be turned in the lathe and attacked with emery.

When I served my apprenticeship in the A/c industry, we wern't allowed emery cloth on aluminium - wet and dry yes. Reason - emery particles embed themselves into the softer materials, so beware. Brass/bronze etc - don't use emery for moving parts.

Isn't wet & dry just emery with a waterproof glue?

As to sawing straight I think it is a bit ike learning to walk, throw, write, ride a bike. After enough practice the subconcious brain learns to handle it. It is part of the way humans are designed to pick up skills.

Modern day hacksaws dont help, cant beat the Eclipse of yesteryear.

No problem filing, i was one of a handful worldwide that did ultra precision stuff cnc couldnt muster. Rough guide vice at elbow height and watch what you are doing.

Most wet and dry are silicon carbide but not much use for hand cleaning up. Need something with a backing ie emery cloth more than likely aluminium oxide which may embed in soft materials.

Regarding grit, its easier to work down the grades but make sure all the nasties are out before progressing. Else you will have to start again repetitively. Of course you can get a shiny finish on skimped work but will show up every imperfection the higher you go. Grits will wear out and give a finer finish, i used to save some 600grit that had gone flat for mr perfectionist jobs. Waste of time going 1200gr and wire wool waste of time.

Not fond of draw filing, it puts scores in the work and have to be fetched out risking scrapping the job. Roughing out no question its right, i used a 3 square 12" bastard.

Its all a case of working and finding which abrasives work best on that particular material.

With all forms of polishing there are rules; break then at your peril

1. Remove all machining marks with a file. unless your surface finish is good. The file might be a

needle file or a 12"bastard. You must use your common sense here.

2. Now start using abrasive cloth, starting with something like 100 grit. Do not try and use a 4" x 2" block fold you abrasive cloth in half so that you have strip about 20mm wide, now get yourself a piece of wood again 20mm wide by 8mm thick and form a chisel point on the end wrap the cloth round the wood lengthways start working a small area to be polished. This should be at 90deg to you filing. Work away until you have removed all the filing or maching marks. The abrasive cloth should contact the work by about 5mm hence the chisel point. Complete the whole workpiece like this.

I forgot aluminium oxide cloth is best on a flexible backing not cheap but worth it.

3. Repeat the above step with 180grit again at 90deg to the previous abrasions.

4. Repeat with 240 grit

5. Repeat with 320 grit

6. Repeat as many times with finer grades of by now wet'n'dry as you like, remembering allways work at 90deg to the last grade of abrasive. by the time you get down to 1200 grit you will have a mirror finish. By this method you can retain square edges which with a buffing wheel you will not.

Edited By Dusty on 20/09/2012 20:14:23

In the Watchmakers catalogues they advertise, 'Buff Sticks' in various grades and these allow you to gradually go through the grades 1 2 3 . They give an excellent finish and are also usefull on the lathe.

They last a long time and also work on Brass as well as steel items. The coarser ones I have used to sharpen Knives and Pruners.

Clive

I guess what is important is to try not to get too many marks in the first place.

I have been using the back of a piece of wet & dry to reduce the marks with some limited sucess.

If you look in 'My photos' you can see a Pipe bender that I have made, no abrasives were used only a smooth file and chalk to give the finish on it !

I 'Break' all the edges so that there are no sharp corners or burrs to cut and catch up on. I slightly countersink all hole edges and clean up all internal machine marks so ta there are no loose fits.

Clive

Hi Chris,

Bright Drawn, isn't always that 'bright' let us have a photo of the material and we could perhaps give better advice or reassurance.

Regards

Terry