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Member postings for tractionengine42

Here is a list of all the postings tractionengine42 has made in our forums. Click on a thread name to jump to the thread.

Thread: Hydrogen embrittlement
18/12/2009 22:07:35
Hi Everyone
Thanks for your kind thoughts and advice, It's very simple, I can take advantage of this time of year. A wad of cash and instructions to her in-doors to go and buy my xmas present, I will tell her I want a set of smooth faced straight curved safety spiral tanged files, then her in doors will be out door for a good while and I will just have to be dis-appointed on xmas day. I need to act fast though, time is running out.
The only problem is, I will need to ask her for a cash advance to have the cash to give her, as it's for my pressi I am sure she will oblige. No problem.
 
Nigel
18/12/2009 17:58:48

 
Hi everyone

Ian - I seem to recall the de-embrittlement temperature is around 190 deg C and has to be done 4 to 6 hours after the coating process and baked for several hours. If not done in the required time span hydrogen becomes permanently trapped and the heat treatment does not work.

 Meyrick - It's actually a 3" Allchin I am building but a Burrell is close enough. The parts in question are for a motor cycle restoration project being done by a freind, he gave me some large socket head cap screws (probably 12.9 grade material) from which to make the parts and wants to get them black phosphated. It occurred to me that with this material hydrogen embrittlement might be a problem.

 Kwil - I did not mean to infer that hydrogen embrittlement is a problem with anodising, only that by treating the component surface the load bearing capacity was effected. I think perhaps the anodised surface in less ductile and more susceptible to suffering a minute crack under certain loading conditions from which a larger crack may propagate especially in a cyclic loading condition, only my guess.

 I conclude that de-embrittlement is a safer route just in case. At 190 degC it can be done in a domestic oven.

Thanks for your helpful comments

 Nigel

 

 

Thread: Flanging tender side panels
18/12/2009 17:39:32
Hi Ian
Thanks do much for your post, I had not thought that the resin could peel off but now it seems logical that it might. I have plenty Isoflex liquid rubber and primmer left over from fitting the rubber tyres so I will probably use that. Another person did mention Isoflex.
 
Not sure that hot dip galvanising will be good for getting a flat and pristine paint finish on the external surfaces. Maybe a spray galvanising or something.
 
As a matter of interest ;I collected my profiles and plate material today, so this week end I make a start, first job is to radius the former. I supplied a dxf file which the profile company had no problems using, I had imagined that I would need to do alot of work cleaning up the former edges but they are very smooth and even , I hardly need to do anything, A lot different from what I remember when I was working in a workshop 30 years ago.
 
Thanks again
Nigel
Thread: Hydrogen embrittlement
18/12/2009 03:46:36

Hi

Many metal finishing processes add hydrogen to the material, for higher strength materials I think above 1050 N/mm2 tensile require the hydrogen absorption to be released through heat treatment within a specified time period. With out the heat treatment tramped hydrogen causes the material to become brittle, the component can fail at a fraction of it's normal capability.

 Does anyone know if hydrogen embrittlement can be a problem with black phosphate coating? I think any phosphate coating adds corrosion protection by converting the surface of the material bugt is hydrogen absorption take place?

 Maybe hydrogen embrittlement should be a safety alert subject for those not experienced with the effect various processes have on materials. I heard of a case where someone anodised an aluminium aircraft part and because of it this highly stresses part failed.

 Thanks

Nigel

Thread: Flanging tender side panels
13/12/2009 04:03:50
Hi Francis
Thankyou for your posting, very interesting approach. Where you using brass or steel for your tender? Did you anneal the material through out the formimg process? How did this work out using a hardwood former?
I have already ordered some profiles from a local company as suggested by Jason, I am still a little anciuos about forming the 2mm mild steel around the former so I have ordered extra mild steel sheet, what you learn from the first always means the second is better. If I live long enough to build a second engine it will be better than the first. So this flanging exercise is my xmas project, i hope to have a happy xmas.
 
Nigel
Thread: Washers
13/12/2009 03:34:36
 

Hi everyone

I am a consultant in the bolting industry, it's my job to design tools, calculate bolting requirements and provide procedures. Provided correct lubrication is applied washers are not used unless there is good reason to protect the surface of the component. On critical applications with high bolt loads thick hardened washers may be used to assist in load distribution and tightening method. Lubricants such as copperslip or coppaslip are termed anti-seize compounds, they lubricate for tightening then give corrosion prevention to assist in loosening. You have to be very careful which compounds you use depending upon bolt materials and operating condition.  Spring washers etc provide no benefit on structural applications, correctly designed and tightened joints don't need any additional feature, or locknuts or anything, There are a couple of exceptions that employ tab washers or heavy duty Belleville washers. On critical joints use anti seize compounds, normal grease and oils increase the torque required and reduce control over bolt load. Don't use molybdenum-based compounds unless you know what you are doing, you could put a critical joint into a dangerous condition.

 

Nigel

Edited By tractionengine42 on 13/12/2009 03:38:17

Thread: Finishing a casting
09/12/2009 21:04:09
Hi
Halfords sell JB weld and high build primer. 2 or 3 coats of high build primer rubbed down with very fine wet and dry paper used wet gives a super smooth finish. I casting I did recently was like a morror after spraying with  pheonix enamel.
Nigel
Thread: Flanging tender side panels
04/12/2009 08:24:00
Hi Jason
Very much appreciate your very quick response, your tender construction looks very good and the photo's are very informative. I had thought that cold working would not be an option for steel and that a red heat would be needed but you have convinced me different. From what you have shown me I now have the confidence to go head in the way you suggest. There are some pritty heavy bits of steel thier in the formers, this should be interesting. I wish I had asked ages ago.
 
How did you water proof the tank? I was thinking of using fibre glass matting and resin that you can get from auto shops such as Halfords, thought it would be a cleaner method than painting with liquid rubber, mind you I have plenty liquid rubber left over from fitting the tyres.
 
Many Thanks
Nigel

Edited By tractionengine42 on 04/12/2009 08:28:11

03/12/2009 03:06:44
 Hi
 
I am building a 3” scale Allchin now well advanced. Not having oxy acetylene equipment I thought it would be better to buy the tender side panels and other parts ready made and flanged from a supplier, having now waited 18 months, and despite repeated phone calls, there is no sign of delivery. Now desperate I need to find away to make some progress.

My question is, is it feasible to do this work with a propane gas torch? The problem I see is that the heat needs to be very localised and heating to large am area will deform the steel plate. I will be using 2mm mild steel plate.

 Any suggestions on what approach I should take to do this work would be very much appreciated.

 Many Thanks

Nigel

Thread: workshop and tooling requirements
22/11/2009 00:59:45
I seem to have lost the end of my post !!!
here is the rest, for what it's worth.

Being dimensional bi-lingual I do confuse younger people by talking both metric and imperial in the same sentence, its a symptom of having been taught imperial at school and metric at collage, my first day at collage was the day they decided to go ISO. >>

 >>

Hope my rambling help>>
 
Nigel

Edited By tractionengine42 on 22/11/2009 01:01:05

22/11/2009 00:52:29

Hi Steve>>

Regarding metric or imperial, you might want to consider whether you will mostly cut metric or imperial threads. I bought an imperial lathe for the imperial lead screw as most of my threads are imperial, this allows me to use the thread dial indicator when screw cutting which is easier. >>

 >>

If I was to ever cut a metric thread then I would need to keep the lead screw half nuts engaged and reverse the chuck between cuts to get back to the beginning of the thread. Not a problem but not so pleasurable.>>

 >>

If you are OK with both systems I don't think it matters which you choose, if you are following published designs then you are more likely to cut imperial threads and a metric system will mean allot of conversion from imperial, an imperial lathe will be more convenient.>>

 >>

Going off on a tangent, these days there is a drive to dual dimension drawings, you will need to check dual dimensions as dimensions converted from imperial to metic and rounded can introduce errors. Having said that, when making models you should plan ahead, check drawing dimensions and model dimensions before cutting metal.>>

 >>

As it happens my lathe has dual metric and imperial dials, this combined with the imperial lead screw is ideal for me and I am very happy with my choice. >>

while I am happy with both systems to my surprise, I do find myself converting from imperial and using the metric scales. Being a lover of the 'thou' I never thought I would do that. >>

 >>

Someone is sure to mention DRO.s which are great for working in either system but I think are an un-necessary expense when setting up, better to expand your range of tooling first. If you are cash rich then get DRO's>Thread: Why do I do it?!

18/11/2009 14:35:44
You learn from your mistakes, I am becoming very well educated, still alot of lessons to learn though.
Nigel
Thread: O-ring coming off pulley when motor power is cut
11/11/2009 00:07:50
Hi
My thoughts
'O' rings are an elastomer and very elastic, under a heavy breaking load induced due to the momentum of parts rotating, one side of the 'O' ring could be stretching significantly, as this happens the opposite side will become slacker and more vulnerable to coming off the pulley. It would be better to use a stiffer belt material such as polyurethane. You can get small section polyurethane cord  which you cut to length then mould the ends together, one way to do this is to cut the ends square, heat a thin piece of metal to a temperature that softens the polyurethane, place the ends either side long enough for the polyurethane to begin to soften, quickly remove the metal and push the ends together.

I you want to stick with an 'O;ring then a thicker section may stretch less under the breaking load and stay on, other than that the roller clutch or pulley flanges suggested above should cure the problem.

If the 'O' ring you are using is stretching significantly under breaking load it could be prone to failure and therefore, if using the same 'O' ring a roller clutch would be the better solution.

Some small machine tools use small section polyurethane belts, I thick the Taig is one, may be one of these will fit.

Nigel
Thread: HELP HELP HELP - Warco 1224 Gear Head Lathe
01/10/2009 00:47:20

Hi>>

0.1mm taper over 50mm seems allot even for a lathe fresh out the box, over the length of the bed it seems to me to be allot of twist to correct. I wonder if the headstock its self was properly set up in the factory. However, you would have to make sure the lathe bed is set up flat and straight before adjusting the head stock and their lies another problem, you are really relying upon this being accurately set at the factory. . I have the belt driven worco version and the head stock only appears to be held with 4 bolts and nothing to key in its alignment with the bed so it depends on it being properly set in the factory.>>

 >>

I also had a terrible time getting alignment. After a day of frustration I welded 2 substantial bars across the base of the cabinet (front to back) at each end and fitted 3/4" jacking screws. It still took me a couple of hours to get close; it turns perfectly parallel up to 50 mm from the chuck then tapers 0.05mm. This I have come to live with, for accurate work I either finish by hand, with emery, or try and keep the turning at a position where it turns parallel. As a result I have never felt happy with the machine as this problem takes away the pleasure some what.>>

 >>

This lathe has a gap bed, I have never removed the piece that fits in the gap, its my guess that as I adjusted the jack screw, thus twisting the bed, the piece in the gap does not twist with it and is now out of alignment with the main part of the bed, so I wonder if the head stock was ever correctly set up and should have been adjusted. I have decided not to loosen the head stock and make adjustments that way as I can see myself getting into a right old mess.>>

 >>

I work away from home allot and bought a Sherline so that I can make parts while away; I chose it because it is light and portable. What a delight to start using a machine with no issues, perfect alignment and real quality feel. This I am very happy with.>>

 >>

Nigel>>

 

Thread: Lapping valve tapered plug
24/09/2009 14:42:55

Hi Meyrick>>

Thanks for your reply>>

I was being led by the drawing saying grind in the valve plug but what you say sound good to me. Basically making the cutter/reamer and plugs at the same setting and keeping the quality good means there should be no or little problem.>>

 >>

Unfortunately I work overseas most of the year which some what slows progress on my Allchin. However, I have a small Sherline that I use in my overseas apartment so progress can be made on smaller parts. I will make these parts following your advice but will not be able to test them until I get back to the UK in December.>>

 >>

Again Thanks>>

 >>

Nigel>>

 

19/09/2009 09:19:49
Hi everyone
I am building a 3" scale Allchin, I am looking at making the draincocks for the cylinders which have a tapered plug. The drawing says the valve body and plug tapers should be ground in. I am concerned that if I lap/grind them in using a diamond or similar grinding paste then the abrasive is going to become embeded in the parts. (The drawing suggests bronze for both parts). I was just wondering what procedure is normaly used, is there a method of lapping in the tapers without impregnating the parts with abrasive? At this scale the plug will be 1/4" diameter.
 
Many Thanks
 
Nigel
 
 
Thread: Boiler regulations update
13/09/2009 03:10:54

Hi >>

As a grumpy old so & so I enjoy all your rant and rave but it's not answering the question. I seem to remember way back that one or some of the model engineering associations worked with HSE regarding our boilers and some common sense was agreed in the form of a standard which was published in ME. If this is correct it would be helpful if the ME associations could work with ME magazine, and post the regs as they apply to us on this site. This is important information may of us need so easy access would be a great bonus.>>

 >>

All this traceability seems to be about tracing all those that can be held to account for what ever has gone wrong, as such you would expect all those along the line to take more care in providing what ever it is they provide. >>

 >>

Although I agree that HSE goes over the top, for such a critical item as a boiler some commonsense easy to apply standard guidance would be of benefit. I believe or boiler designs have stood the test of time and are very safe designs so there safety is down to the individual construction and the final tests.>>

 >>

Were regs published in ME or am I mistaken?>>

 >>

Regards>>

Nigel

PS Due to a glitch I may have posted this twice!

Thread: crankshaft bearing material
12/07/2009 05:00:32

Thanks Duncan for your suggestion to use white metal, that sound interesting and will be a new experience, I think I will give that a go, in a year or two though.

05/07/2009 03:44:29
Hi Meyrick, thanks for your reply, very much appreciated, you have confirmed my fears but as you sugest there is no need to panic now, As you suggest I will finish the engine and get steaming then line the beraings with 660 bronze during winter workshop hibination.
 
You mentioned BS recommendations, do you know where I can find info on BS recommendations for bearings and shaft combinations?
 
 Kind regards
Thread: acid pickle
27/06/2009 02:47:06
Hi
I bought a motorbike battery on ebay for £12 which came with a separate electrolyte pack. I bought it for the battery, not the acid. Probably an expensive way to buy a small quantity of acid. The Citric Acid route seems a safer and convienient.
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