Cleaning up corroded dials

[John CoatesParticipant @johncoates48577]

Hi

 

My 1947 lathe has corrosion on the dials on the cross and top slides

 

I have had a little go with some emery cloth but it seems that when I have removed most of the corrosion the dial marks and numbers are very faint

 

Reluctant to proceed any further I wonder if there is a better way to do this or else is there a way of getting the dials remarked with new divisions (presumably these are 5 and 10 thou divisions) and numbers

 

Thanks for any replies

 

John

 

1947 5″ x 24″ Barker roundbed lathe

[John CoatesParticipant @johncoates48577]

On cross and top slides

[Frank DolmanParticipant @frankdolman72357]

    1.  Buy and read Geo Thomas’s “The model engineer’s workshop manual” and

  “Workshop techniques”   You will then know how to do it and how to make the

   necessary kit.

 

     2.  Resolve to do it when time and money allow.

 

     3.  Degrease the scales very thoroughly and reinforce the existing marks

  using a steady hand and a drawing pen with indian ink.  This will last surprisingly

  well but not so well that you ignore the advice in  (1.) for very long.

[russellParticipant @russell]

i have a similar problem with my elderly drummond. i’ve wirebrushed the dial, but need some way to properly clean out and fill the markings (some of which are very shallow).

 

I’ve tried using a carbide tip scriber to clean the lines, but very little effect as the dial appears quite hard.

 

Frank, i think you are suggesting rescribing the lines using some sort of gadget? Is it possible to get them lined up well enough, or is it just easier to make a new dial?

Is there any benefit to steel over aluminium? What is the best way to make the lines high contrast?

 

so many questions….

 

russell

[Frank DolmanParticipant @frankdolman72357]

    My advice to read Geo Thomas is the core of this.  He explains, in good detail,

  how to make all sorts of dials from scratch.  If you decide to go the whole way,

  an awful lot of tooling is required but it is all stuff that a complete machine shop

  should include anyway.  Some weeks back, in a different thread, Meyrick

  recommended a Versatile Dividing Head, a Universal Pillar Tool and a Quorn.

   This represents a dreat deal of time and, by my standards, quite a bit of

  money but just about the best, if well made.

 

    There is one addition to my previous post.  The Bodger, using indian ink,

  will find that it will stick to the steel better if he gives a wipe of Jenolite first.

 

    Read Geo Thomas

[Michael Cox 1Participant @michaelcox1]

I dont know whether this would work but you could try etching the cleaned up surface with ferric chloride solution (this is easily obtainable from Maplin as it is used for etching printed circuit boards).

It is likely that the etch would attack areas of stressed metal faster and the most highly stressed areas will be those around where the graduations were scribed when the dial was made.

Mike

[John CoatesParticipant @johncoates48577]

Frank

 

Had a look on Amazon for the George Thomas books – nearly £80 the pair! – so can see what you mean when “time and money allow”

 

My first plan of attack will be to restore the existing rather than replace with new

 

Thanks for the help guys

 

John

 

[John Stevenson 1Participant @johnstevenson1]

I had an old slotter years ago with a dial about 1.5 ” in diameter with 200 divisions on it, although clear it was impossible to read.

I made a new dial al lot larger  and then drew 200 division on my CAD program where base line equalled Pi x the diameter of the new dial.

Printed this out and wrapped it round but it was slightly out so rescaled the drawing a couple of times and got one to fir exactly then wrapped some cellotape round it to protect it.

 

Worked remarkably well and I was able to choose clear numbers etc.

 

John S.

[Frank DolmanParticipant @frankdolman72357]

     Whoops, £80 for Geo Thomas eh John!  Mine were much cheaper.  Still, you

  must read them.  Find a ME smaller than yourself and “borrow” them!  By the

  way, I am a lot bigger than you.

 

     Ferric chloride will not etch steel, Mike.  I don’t think that faster action on stressed

  metal will be enough to make a visible difference.  Phosphoric acid ( Jenolite )

  will etch steel, so will sulphuric.  Hydrochloric works but somehow seems to

  leave behind it an increased tendency to rust.  I don’t believe unmasked

  etching will be successful.  If you try it and win, I am prepared to look silly!

 

     Frank

[Michael Cox 1Participant @michaelcox1]

Ferric chloride will etch steel, Frank. It is a standard etch used in the metallographic examination of steels. On badly polished samples it will reveal the lines caused by the initial grinding the steel on wet/dry paper even though the polished surface is quite plane. It was this latter observation that prompted my original comment.

Mike

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

 I thought Amazon were meant to be cheap, the publishers price is £50.90 +P&P for both! someone somewhere is ripping the public off big time!

On the graduating theme, I did the same as JohnS for the dials for my Quorn, I used an ink jetable shiny “silver” film and when I made a new dial for the Barometer I was restoring, I used Laser printable water slide material.

When I made more permanent dials for the Quorn I used a 10 thou thick slitting saw in the mill to cut the lines, as some of you may have seen at a show or two. I have been asked to put it on the SMEE stand at Sandown, so if anyone is interested they can see it there, only static display though I am afraid. It does work in steel, by the way, getting back to the original post.

chriStephens

[John CoatesParticipant @johncoates48577]

Thanks Chris

 

Those prices are a lot more within my family’s budget for Xmas presents so I’ll point them towards the Tee Publishing website   

 

In the meantime it’s back to painting the garage where the lathe is going to go

 

John

 

[Frank DolmanParticipant @frankdolman72357]

 

      Your information is so impressive Mike that I shall consult Mother Nature

  the ultimate authority, and report further.

[chris stephensParticipant @chrisstephens63393]

Hi John,

If money is tight, when isn’t it, I would pick the “The Model Engineers Workshop Manual”.

“The Workshop Techniques” is mainly concerned with making making the UPT and the VDH.

chriStephens

[michael birdParticipant @michaelbird72946]

Frank Dolman mentions Jenolite in his reply, can I ask him is this still available, and where I can purchase it from online.  I have read many mentions of Jenolite in car restorations books, but having searched extensively cannot find a supplier.

 

Michael Bird.

[John Stevenson 1Participant @johnstevenson1]

Well I have been doing engineering professionally for umpteen years now and have never read Thomas.

 

Am I missing out here? 

 

No one told me it was compulsory reading before switching a lathe on.

 

John S.

[Frank DolmanParticipant @frankdolman72357]

     My Jenolite came from a motor factor a couple of years ago.  £7 for half

  a litre.  This was the watery variety, not the jelly.  If this is another good thing

  that has vanished, I shall mourn it. Shell Care International Ltd 0161 935 7490.

   Usual Disclaimer.

[chris stephensParticipant @chrisstephens63393]

Hi John,

One will have one’s little joke. You know perfectly well that most of what is in GHT’s books you could have written yourself, but he got there before you. 

One trouble with not being a trained machinist is that you have to swot up a bit sharpish, his writings help those who worked in other fields to learn a few things that might have taken years to learn by themselves.

If you need more lining for your downstairs reading room you could give him a try. There will be things you agree with, but then again, you will find things that you could do better. Ask any dozen engineers a question and you will get a dozen or more replies, but with GHT you get workable answers that (fairly) newbies will comprehend. Hopefully!

The other John Stephens’son

[Geoff SheppardParticipant @geoffsheppard46476]

The ‘Gospels according to St. George’ are a valuable asset to any newcomer to the hobby. His methods are sometimes a bit over-complicated and long-winded for those who know what they are doing, but following his instructions always seems to come up with the right result. Most of the content of his books was originally published in Model Engineer and there are thousands of back numbers available at next to nothing if you go looking. Our club hut is stuffed full of them, all looking for a good home. Going on to Colin Usher’s index will soon tell you the ones you are looking for. The only draw backs are (1) that you have to have somewhere to store them and (2) that you will soon get side-tracked by lots of interesting articles and potential new projects so that you will forget what you were looking for in the first place!

 

Jenolite gel is still available. A colleague has just sourced some off the internet from one of the car restoration suppliers. More readily available now seems to be a gel from Hammerite which I have just obtained but not yet tried. 

 

Geoff

[Frank DolmanParticipant @frankdolman72357]

     Mother Nature says Mike Cox is right and that my brain hs gone like a tin

  of RTD.  I’m not going to tell you what my punishment is, I’ll just say it is

  condign.  Ferric chloride will etch steel.

[pcb1962Participant @pcb1962]

George Thomas’s books are available from Tee Publishing (google it) at 23.95 and 26.95

[Phil AshmanParticipant @philashman88468]

Michael,

 

It looks like Jenolite is available again. Look on http://WWW.Jenolite.com

It comes in liquid, non drip liquid, and jelly.

 

Phil

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