Metal finishing

Ok so I can now turn & mill things to reasonable accuracy but how do you get from an object that looks like it was made from BMS to something that looks like it belongs on whatever its fitted to. Or put another way 'that's a nice model of a train made of metal' to 'that's a train' ? None of the books I have thus far really cover the subject.

I'm rebuilding a Stent T&C grinder and whoever made it has taken a lot of care to get eg flat surfaces looking clean with crisp edges so I'm keen to make my new parts to the same standard. I don't mean the sliding surfaces - those have been surface ground.

Any pointers to web pages old MEW article books etc or advice would be much appreciated.

Tony

Hello Tony!

I made a search in my application and found 52 records where the string "finish" is contained.

If You are interested I can send to You a file containing a list of the issue, page, article title, etc. from MEW where that string was found.

Addicionaly if You want I can make another query with different criteria, please let me know.

If interested send me a message with some e-mail address whre I can send the file to.

Best regards

Dias Costa

95 % plus of what comes off your lathe should have a good enough finish straight from the tool that it does not need any other work. For that last bit Emery, Scotchbrite, garyflex etc can be used.

J

Hi there, all,

Shouldn't sliding surfaces be frosted with the hand scraper to provide some oil retention?

Best regards,

Swarf, Mostly.

Thanks to Dias -pm sent.

Jason, generally lathe work is not a problem; its the unfinished eg on drawn BMS and finished side of milled items mainly.

Swarf, Dunno it will be intereseting to see what others think !

Tony

So its basically removing machining marks on flat surfaces in which case same applies drawfile with a dead smooth file if the marks are heavy then emery or your chosen adrasive.

Have a look at this, just emery, I assume thats the look you are after, that was only taken down to 150grit as I don't like it looking too polished, just a nice even satin finish

Nice work Jason.

Russell.

Jason,

Yup, that's about it.

Thanks also to Dias - I have found two interesting articles in the Digital Archive of MEW:

Surface Finish on Metals MEW July/August '97

The Appropriate Finish for Tools and Workshop Equipment MEW August '99

Just need to practise now !

I have searched the forum on metal finish and found this, but its not quite what I need to know. I need to mill a piece steel plate on the mill 150 x 75 and would like a good milled finish. I've been told on this forum that taking off .2 mm or less will blunt the cutter edges, best use the sides of the cutter for edges of the material when using the end mill. The plate at the moment needs around .2mm to remove the rust but I want the nice lined finish, so it looks quite professionally done. I have a few 15 mm end mills and 16mm slot drills, but as I said I don't want to blunt the edges of the cutters. Sorry if this is a bog standard question thats being asked but I only mill aluminium and try to avoid steel if I can.

I believe there is stated somewhere what are the absolute surface finish limits generally established for machining/ turning.

Michael W

Dust it off with a fly cutter

Bob

You might want to try flycutting the surface. You could easily fly cut 75mm in a single pass, and with a sharp cutter and a fine feed the finish will be very good.

A 2" / 50 mm face cutter with 3 TC cutters works well, I also have a fly cutter with two radii, 5.5", and 3", for that I have both TC and HSS tools. Finish for me depends on speed and feed, and how well the item is clamped down, and lock the slide that's not in use. For very fine cuts, a HSS tool, be prepared to cut the speed to suit the diameter of the tool, and feed slowly but steady(don't stop).

Ian S C

This advice is to tell beginners not to be too timid and does not mean you can never take small cuts. In fact it will often be the case that you have got most of the way there in a series of chunky cuts but it is a brave man that takes a half inch finishing cut intending to get to half a thou of the final dimension.

Bob I think in an earlier post you wanted to remove quite a bit from a similar block so advice was to use more of the edge of the cutter. I is possible to use a sharp endmill to take a series of cut usually about 2/3rds the cutters dia as a finishing cut. This has the advantage over a flycutter of giving a flat surface even if your mill is not quite trammed correctly, I quite often use it to do valve faces etc.

You do need a good sharp cutter and well adjusted machine as if not you will get aseries of nasty looking rings where the blunt cutter gets progressively pushed up off the surface and then bits and drops down again.

I was going to give John " Bogstandard" as a reference but he seems to have vanished? Shame really, I enjoyed his banter/good moods / bad moods, anyone know what he's up to?

Still posting on other forums but not been in the best of health lately, just had a lung removed.

I use two methods to get a good finish on flat surfaces, fly cutting and sand blasting. I have been asked if the pictures I’ve posted on some other forums were actually 3D renders they looked so good!

Thanks Jason, does he still post on MEM? I do miss the forthright and sometimes grumpy old git's posts!!

Mostly on HMEM

Edited By JasonB on 16/12/2017 07:46:28