Member postings for Jerry Wray

Eric,

Etching primer is the most satisfactory process available without industrial scale methods. These industrial process involve tanks of so-called chromating solutions operating at elevated temperatures under time control.

Much work was done by the military, especially in the US to develop a suitable method of obtaining adhesion to aluminium/aluminum at room temperature.

The eventual discovery was the 2-pack etching primer consisting of a base, yellow containing zinc chromate using polyvinyl butyral as a binder and a separate activator containing phosphoric acid. These have to be thoroughly mixed and the resulting primer applied within a few hours. The mixture reacts within itself and in about 8 hours becomes ineffective. There is no need to abrade the surface to be painted. In fact abrasion of the smooth aluminium is counter-productive as these primers have very low build.

These 2-packs provide the best adhesion as they
1 etch the surface due to the acid,
2 phosphate that surface providing a degree of protection against the re-oxidation of the aluminium and
3 also yield a surface to which the next coat of paint can adhere.

Developed from that know-how are self-etching primers, these are totally dissimilar from the 2-packs, but are simpler to use. In the sort of service which hobbyists enjoy they normally prove entirely adequate.

In the aircraft manufacturing and maintenance industries various other formulations are employed based originally on epoxies and more latterly on polyurethanes These are outside the scope of amateur use but meet the specifications for resistance to the various chemicals which are present on an aircraft. Especially resistance to hydraulic fluids.

Just for the record and to add to the fount of human knowledge on what is a most complex problem. Much is shrouded in the mysteries surrounding military applications.

JerryNotts

Ian S C

May I ask what your references are for the withdrawal of the use of PTFE on frypans?

Jerry

I note with interest Michael's post above which links you US sources.

If you don't have an interest in safety of chemicals don't bother reading ths, it's tedious but as this is my day job I feel I need to contribute to the sum of human misery by a short teach-in.

Regrettable these give a somewhat restricted view of the toxicology of PTFE.(Cas RN:9002-84-0). Congess has recently decided to implement the GHS (Globally Harmonised System of Classification and Labelling) to address shortcomings in the present system,which willin the future require any MSDS to actually provide information rather than generalities. US MSDSs are not valid in the EU.

The relevant EU document is known by the acronym SDS (Safety Data Sheet). These contain specific information conforming to regulation and based on validated testing regimes.The ECHA (European Chemicals Agency) based in Helsinki is managing the REACH system and publishes various pieces of data. If you go to their website **LINK**
and key into the search box the CAS number 9002-84-0 (not forgetting to tick the agreement box you will find the EU Harmonised classification which indicates in coded form the various hazards of this chemical.

Further searches within the ECHA website will reveal the basis of this information; which is backed by peer review. Details of how to carry out such searches are beyond the scope of this post.

I warned above that this was going to be tedious.

In the end the ECHA classification confirms that PTFE is as bad, possibly worse than Michael has indicated.

Happy reading.

Jerry

Sorry John,

Can I take it that there are no known accidents amongst the model engineering fraternity traceable to that cause?

Jerry

Thank sfor the shelf picture JasonB. Good idea. I've always been short of space near to the point of use.

Jerry

I question the use of fluorescent lights with rotating machinery.

Jerry

I have followed the various links, In general I find not following can cause me confusion into the future. I have looked at the Arc set, it seemed to arrive on their site whilst I was composing my original post.

I don't know why the impression that I was a beginner came from, as the thread seems to have become about the needs of such a person.

Where I worked until recently the culture was such that a test of newbies to the company included the ability to off-hand grind tools, including Morse drills. No skill, no job. Most of the 'old-man's' staff had been with him 25 years or more.

The thing that is new to me is the much smaller sizes than I have been used to, mainly working on special aluminium alloys in 'suck-squeeze-bang-blow' machinery so scaling down is my main concern. Hence my questions.

Jerry

Jason,

I have taken on board your comments, especially since I will be getting my lathe towards the end of this month, as you know it will be the same as your own.

As yet I have not purchased any new tools; I have the tipped ones from my Cowells and what remains of the tooling from my ML7. It seems that all the suppliers have only sets available for 12x12 HSS, I may decide in the end to grind my own from blanks using perhaps 10x10 for the set-up.

2 questions please,

How do you get on with indexables, and

are your tooling shelves in the picture fixed to the splash guard?

Jerry

Hi Russell,

Fair comment but in m/c set-up it's all about rigidity and eliminating as many sources of error as possible.

Jerry

Thanks to you both. I was actually in the Arc site when I posted my messge. I could not find the preground tools.

I am expecting my new 280 V-F at the end of the month so want to avoid grinding my own shapes in my anticipation of getting the m/c up and running!

Jerry

I used to be an avid reader of ME; as a member of Reading SME I collected as many issues as I could get hold of, free from other members or bought through various newsagent such as WHS Martins and others. I probaly read 90% of them cover to cover. (and No I haven't still got them; my ex probably binned them around 1990). I continued to subscribe for a while but no longer. I'm afraid Diane's 10 different topics in 10 weeks bears little relationship to how often these same topics illustrated by the covers have appeared over the life of the Magazine.

The older issues were very absorbing but after 1950 or so they became very repetitive. As the construction of many projects for the average person with a normal need to earn a living takes a long time, several years in many cases, any issue needs to have some thing which is interesting, and not necessarily focused on the acquisition of new skills. As we get older most of us reach our own level and the learning curve becomes steeper. Experience tells us that everything now needs a purpose, rather than being entertaining, otherwise the isiot box in the corner beckons us.

In my forties the construction articles could be viewed as a challenge but now with many of the similar articles I look at them in the same light as with my reading.

When I pick up a book, newspaper or journal if I don' find it grabs my interest within a few pages then it's not for me. With limited horizons is it worth my time? I may not be around tomorrow.

Sorry to be Job' comforter but for most of us that is the way we find ourselves thinking.

Jerry

I almost cannot beleive I need to ask this question, but....

There's always a but.

I have searched all the usual suppliers and can only find one supplier of HSS tools, that is Warco.

Surely there are others! I mean tools not blanks.

I'm looking fot 12mm or half-inch square x 100 - 150 mm long.

I can find several sources of carbide an inserts but not good old-fashioned HSS.

Any suggestions?

Jerry

I'd like to second(?) the positive comments about Cabeng's guidance on the use of inserts. Very good advice for someone coming from a 'big' machine shop where inserts rule the roost. As my expertise is in the coolant/lubricant side I rarely get to see the results of tip changes.

Thank you Cabeng

Jerry

Hi to all contributors, with thanks,

It looks as though the advice tends to a choice of 2,

ER perhaps 25 or 32 relatively cheap but not the most accurate, or

5G much greater accuracy and cost.

As I have a particular job in view for when my soon to be machine is set-up and levelled, (as discussed in another thread perhaps I really mean aligned?) and this has bearing blocks (brass) to be turned to an accuracy of +- 0.0025" with a mating shaft 105mm long x 20 mm +- 10 microns diameter I might invest in a 5C collet and see how I get on.

Note to self: I must convert 0.0025" to metric!

But in my industry we have to be familar with both systems as often a lab. will work in microns, mm litres tonnes etc when production works with older machinery much dating from the 20s and driven by line shafting still in imperial gallons , and in cu.ins as well as in real money like feet, inches and thou. Our Amerian cousins in the same industry use the US gallon and mils. No wonder we are still confused.

I gather this 20 mm diameter is at the top of the ER capacity range. I don't seem to be able to find an authoritative source of collet dimensions. Not even Tubal Cain's last edition of Model Engineer's Handbook (2003) gives much detail.

Hey Ho!

Jerry

Thanks to everybody,

I'm still not sure of the best way to go. For me precision is what I am lokking for. ER types seem most popular but I take Bogstandards comments to heart. I have looked at his link and the holder he makeswith more than a little interest.

Looks like I shall have to do some more studying. As yet I don't understand the reasons for Jo's use of 5Cs but I hope to find out.

Jerry

Hi All,

I am hoping to get my new lathe at the end of this month and wil be needing to do some work on smallish (up to 10 mm diameter and below) turning for seating bearings. I really want to challenge myself and the machine, after settingup, feeling that collets may be the best means of work holdoing.

In the past I have been loaned various collets of several types from generous friends. I rarely took any interest in the sort of collet, only in its performance in my early ML7, which I no longer have.

My new m/c has a 4MT spindle of 26 mm bore.

I have seen some discussion on hrer but I'm not clear on the conclusions.

Which collets should i buy, ER type perhaps ER25, seem commonly available but what about others,

Opinions most welcome.

Jerry

I have been trying to understand the purpose of the various tool inserts for ssome time. I heard a teach-in by a rep. from one of the tool manufacturers a few years ago explaining the selection of tips for specific jobs on horizontal boring machines.

I never have had an opportuniy to understand the use of these and the appropriate settings. Today I have found what I need, and more, on the Sandvik site. I know that some working in industry will have access to their catalogue which may contain this information but I don't have that access.

The link is **LINK**

Others might find the diagrams and explanations useful.

Jerry

I know this thead has been sleeping since mid-July, but I have only just found it.

I have spent a lifetime working with Chemistry, Maths and Physics experts. Many of them PhDs and some professors in their subject. All regarded by us erks as clever clogs.Mostly they can spout the theories and then back it up with practical examples, oftern on the lab. bench.

However Feynmans' knowledge was exceptional. I recall a television program about him, I think in the late 70s where he explained in fairly simple words a particular piece of work he was pursuing and made it clear and enjoyable. He went on to show the maths on the blackboard, his speed of writing was phenomenal, but he went back through it with an explanation of the steps.

When I got to work next morning several of my colleagues had watched, but none would discuss the maths (that included the mathematicians, one of whom was working on high energy physics) and they all agreed that their maths would not take them that far. I felt that most of them were disappointed about their own level of expertise.

I might add that my maths is in a different league altogether; once I get beyond simple Trig. I am totally lost. Algebra is a closed book to me.

Altogether a loss when he died.

Jerry

Many thanks to all the contributors to this thread, I've now placed my order with Warco, who expect to deliver it in early October.

Andrew, your comment following my 'fun' and twiddling post was understood in the way you meant it. It's amaxing how easy it is to make a remark without understanding that others might interpret it in a different way! To be honest I had not thought of the boundary between various levels of mechanisation.

I now to think about some of the other issues I might have.. For that I will start a new thread.

Once again many thanks for all the useful information.

Jerry

Thanks for all the contributions, most encouraging when the spend approaches £2000 !

Andrew, Glad you pointed out my conflicting statement about fun. I had not thought of it that way.

I have never had a machine of my own with PXF but it seems it's the way to go; I don't have a lot of patience now I'm near retiring and 'twiddling' the feed may just drive me mad.

George; Thanks for the pointers, I'll have to check those things, and of course all the bits that might be less than perfect,

and Jason I am even more encouraged that your experience with the 280 has been good,.

When I get it I'll try to remember to post some pictures.

Jerry