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Member postings for Donald Wittmann

Here is a list of all the postings Donald Wittmann has made in our forums. Click on a thread name to jump to the thread.

Thread: Drilling hole of 0.0310" with deepth 0.91" of AISI 304L
02/12/2011 15:46:23
304 ss is terrible stuff ,could you not substitute it for 303? even 316 is better than 304. That type is really a swine to machine. I have turned it many times over the years and have yet to hear of anybody who likes the stuff. I would be interested to know what properties of 304 is required for your model.
Ps Walter/Titex are amongst the finest cutting tools available expensive but first rate gear.
Thread: Tipped Tools
30/11/2011 17:59:17
What you should be aware of is unless you have a large rigid lathe with plenty of HP behind it then avoid any inserts that end in the letters MG as all the inserts ending with those, are Negative inserts and really require lots of HP and rigidity.
here are some of the culprits, CNMG, DNMG, SNMG, VNMG. there are also a few others that are not so common.
Thread: Clarke CL500M Lathe conversion to Inverter drive
25/11/2011 18:46:50
Try " Inverter Supermarket " they have all the top makes, you will certainly get one to go with your Seimens 420.
Thread: Drilling deep holes - 10x drill diameter - Runout?
31/10/2011 16:53:01
Your drilling is maybe not at fault, The problem could well be that your chuck jaws are not holding the part true to the lathe bed. Even if you set the outer end to a couple of microns the inner end that projects to the rear of the chuck could well be off with the result that the hole [even if it is true] would be eccentric to the outer Ø.
So you should also check your chuck / chuck jaws.
Thread: Chuck Jaw Interchangeabilty
29/10/2011 18:15:53
All chuck jaws are specific to every manufacturers chucks ie Rohm, SMW, Pratt Burnerd et all. For instance Rohm model No ***** needs jaws for that specific model, also replacement jaws are always ground in the chuck they are used in, to ensure the best TIR.
Thread: Drawing Quality
28/10/2011 14:46:42
Who won 2 world wars on the back of fag packets??? or maybe it was a case of " who lost 2 world wars because there was not enough fag packets "
Thread: Facing Cuts - Requires the Carriage to be Locked?
05/05/2011 18:29:39
You certainly have a very good brand of lathe and it should last you for years with the proper maintenance. You should always lock the crosslide when making any facing cut
even Heavy production lathes have a saddle lock for facing or parting off.[Don't ever use the leadscrew to lock the saddle]
I use Castrol Magnglide BD68 at work and it is a top notch slideway lubricant If you envisage using flood coolant at any point I urge you to try Castrol Hysol [very versatile,long lasting and Does not have any bad odours]
Hope, no, I KNOW, you will enjoy your new Wabeco.
Thread: D bit grinder work head calculations
05/05/2011 18:10:43
If I get the time I will ask some of the design engineers at work for the answer to your query. Provided I explain it to them correctly they will be able to give the answer.
I notice Mr Thomas posted a reply, but it did'nt help you one bit,[why am I not surprised?]
Thread: Cross slide lifts when parting off
03/05/2011 17:27:13
Martin B.
If you have the scope of adjustment as regards tool height you could try inverting the parting tool and running the lathe in reverse [ok with bolted on or Camlok chucks] also for en1a steel you should try using the inserts that have a positive cutting geometry they are usually uncoated and very sharp with very low cutting forces. The type specified for non ferrous metals, a good grade will last you long enough on en1
also when parting off the worst thing you can do is approach the task with trepidation parting off calls for a fairly heavy feed and constant cutting. NEVER use a tailstock centre when parting off or the problems you are having just now will be the least of them.
Also for Ø20mm you should up your speed to about 250-300 rpm and flood coolant.
Thread: Engineer's Blue
01/05/2011 16:36:02
Like IanSC says, you can use a felt marker pen just make sure it's a permanent type.
The best type for marking out metals is EDDINGS, although a Sharpie Magnum is a good alternative. Blue or Black does me on bright steels and Copper beryllium, I think Red would be good on Brass.
Thread: Precision Tailstock Alignment
23/04/2011 18:14:01
Before you go adding to, or taking off anything from the tailstock you must first ensure that the HEADSTOCK is set true and there is no twist in the bed. You should turn up a dumbell and held in the headstock and first get that to turn true [parallel] then you have eliminated any error in the head stock. and should only then move on to the tailstock.
it may even be a combination of errors involving the headstock and the tailstock hence the need to eliminate any [if any] error in the headstock . and if you use a clock then use a good one that measures in 2 or 3 microns it might sound overkill for a chink lathe but once you have found out where the error[s] lie then it will make your life a lot easier. in getting your lathe set up just right. How long it will stay like that is another question.
Good luck.
Thread: Technical and engineering drawing.
18/04/2011 19:05:07
Steve I will certainly give praise where it is due,and mean it. Beginners must be given the chance to learn how to interpret engineering drawings that is 1 of the fundamentals, the "fag packet sketches" are quite often only understood by the "fag packet sketcher" and no one else, that is why we have drawing standards, but very few newcomers will be able to fully decipher them without some form of tuition. Im sure that Terryd does not mean the whole kit and cabodle of G D&T but just the basics.
Graham, Yes standards have certainly slipped from Britains once lofty peak. I have seen engineering from both sides of the fence from Germany and Britain and as it stands now there is no comparision . British society, and the education system has a lot to answer for as regards to the lack of pride in the job. I' m not having a go at Britain as there are still some very good Engineering firms left but they are getting rarer. The H&S taking lathes and milling machines out of schools tells it's own story. It pains me to say it but the way things are shaping up Britain will soon be a nation of call centres.
18/04/2011 18:01:12
I did'nt think that I would ever agree with Terryd, but he is spot on with the idea about how to decipher engineering drawings correctly. If you can't understand the drawing[s] how are you going to build the item?
Jesus 2 agreements in 1 day, because Graham is also correct about the frequent use of the phrase "it's near enough". Maybe, just maybe have I begun to see the light? and there is more to the people on here.
Thread: Amateurs
25/03/2011 05:35:30
Jeff, Yes that is the same Michael. although I am not going to get into any discussion about politics, I have enough crap to deal with here as it is!
John S, since the gloves are off and you started with the personal stuff and I am reluctant to lower myself to your level I will make an exception, Your head is so far up your a**s that your almost inside out.
ady, Grovel I have nothing to grovel for even if I did, I do not do grovelling, apologizing yes but no grovelling.
Some earlier poster to this thread [I think it was Terry Thomas] said that the truth always hurts well I feel just dandy, but it must be me that has touched a raw nerve here.
Now I think I will go do some milling using a drill chuck, after all it should be ok as long as I keep the cutting forces down!!
24/03/2011 20:09:12
No I do not have a relation called Ludd but I did have one called Michael [before my time]who was quite famous but no Nedd i'm afraid. I stick with my observations and nothing on here has changed my view.
Raymond, DSG is a superb machine and at least you have brother who is qualified to advise you. And it does not surprise me about the fool with the camloks. Thats the whole point of my argument about bad advise. If someone followed that advise and an accident happened where would we be then? although some on these forums would have you believe such an occurence would not happen.
Such people should stick to making toys they would be far less dangerous.
24/03/2011 10:39:31
Thanks, Stewart and Ian,
I am not a model engineer. It certainly looks like I have put the ball up on the slates people on here seem to have a problem understanding that I am not
trying to belittle model engineers but I must be missing some point here. And for another poster YES I am familiar with the work of Ms Hill, that is my point I could not imagine her giving out crap advice could you? unlike many others, not just here but on other forums.
I have certainly no need to ask advice from any forum but if I myself was asked then I would certainly give the best I could [even if it did mean causing the fur to fly]
PS to the other Donald, it's Wittman
24/03/2011 10:25:05
John Stevenson,
If you read my post I said MORSE TAPER not a steep taper like your photo.
I have never had a problem finding a centre lathe job although I am equally at ease with CNC. as for bulls**t well you would know more about that than me.
I only joined the forum yesterday and have been constantly bombarded with flak.
If that's what you get for speaking your mind then bring it on.
by the way your not Chinese are you?
24/03/2011 08:21:06
Terryd, I have refrained from attacking individuals during this post [I have no intention of] but I could happily make an exception in your case.
mgj, Your experience off AFV manufacture tells it's own story. Why do you think the German Leopard 2A6 is widely regarded as the worlds best. because the men/women who build the things take care to do the job RIGHT. You will find that with all German firms Apprentices are given solid advice and taught "Do it Right " or the door is over there.
23/03/2011 19:40:27
Donald, No I am not a paid up union bully boy. It is just the laughable so called advice that appears on these type of forums. 1 example over on another forum there is instructions on how to build a tram indicator using 2 clocks! no miller that i know of would ever tram their head that way. that,s what I mean about bad advice, the proper and most accurate way is 1 clock and rotate 360degrees. places even sell such things, why have someone pay for a tool that is no use, again bad advice.
Nicholas It bothers me not If I am unpopular. Another of my pet hates is the amateurs complaining about the cost of proper tooling/machines then they go out and buy the latest chinese crap and then start complaining about their purchase. If they can't afford decent tooling/machines then they should take up basket weaving or some other such hobby.
I have a lot of time for people wanting to learn In fact I would go out of my way to help any body who want's to learn but I have no time at all for the "I'll use this Chink tool and then complain brigade" or the Heath Robinson mob.
23/03/2011 18:16:13
Being a time served turner I really wonder about the competence of some of the so called machinists on this forum. Cowboys, being one word that springs to mind. The amount of time that somebody asks a question on here [many times there is only 1 way do do the job] and he/she is bombarded with all manner of quite frankly "stupid" so called methods I thought Heath Robinson was dead many years ago but I'm sad to say he is alive and well Another foible that I have noticed about the amateur is the way they go on about tight tolerances and promptly buy cheap Chinese tools and then moan about not being able to hold said tolerances. when I would blame a combination of crap tools/tooling and them being able to speak a good job but being unable to do the job.
So the bottom line is amateurs are not in a position to give any advice on machining and should stick to making plastic kits.
I will now have a look through some more postings [I could do with a laugh]
Donald Wittman.
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