Here is a list of all the postings CHAS LIPSCOMBE has made in our forums. Click on a thread name to jump to the thread.
|Thread: Silver soldering stainless steel|
David, The 3 light-coloured bricks on top are vermiculite. The base slab is some sort of fire grate brick as I don't have enough vermiculite ones at the moment. . The bored out piece of brick holding the job is also fire brick - same reason. We are in lock down (again) at the moment and I can't find an Aus supplier that will post small numbers of vermiculite brick because of breakage. Someday everything will revert to normal...............I hope.
Keith I really do appreciate the time, patience and effort you put in helping people, including me, on the forum. Especially when my problems this time mostly come under the category of "When all else has failed,read the instructions".
Bill Phinn. As far as I can see with my inexperienced eye, the torch is adequate for this job but I have noted your input and if I'm still in trouble I will have to purchase the kit you recommend. When all else has failed.........!
Dave Halford. That is a good point you raise about the centre of the job being hot enough because stainless is a poor conductor of heat. I don't think it is the problem in this case but it's a point to consider on future jobs
Somehow I have just lost my long reply to all the good folks who replied to my post. Also no luck in getting photos onto the post - looks like I will have to look through old posts detailing how to add photos. Maybe I need to create an album.
I think my troubles are self-inflicted. I had some cadmium free 45% silver rod (BOC 45T) and some JM Easyflow flux and tried those. I could not get sufficient flow through the joint and I see now that the Easyflow flux is not adequate for this situation.
As Keith rightly says, all the answers are in his book, except that I was not sure about the fit required.
I think my rod will be OK for the job. I have some Tenacity No 5 and will try again after a good clean-up and re-tolerance.
I am using disposable cylinders of "MAP gas replacement" which seem well up to the job ( I seldom have need to silver solder so not worth investing in more expensive equipment). This is my first attempt at soldering stainless steel and screening the job with vermiculite blocks.
Interestingly a google search for Tenacity No 5 does not throw up any results but I can find results for other tenacity grades. Tenacity No 4 is available in Australia but apparently not No 5. Would Tenacity No 4 work or not for stainless?
Will try to send photos later. Chas
I have a need to make 12 stainless steel t-handles with the core stock about 14 mms diameter and the tommy bar itself 8 mms diameter. The core is 12mms long and the tommy bar is 60 mms long, so not a big item. This job has not gone particularly well so far, although Keith Hales book has given me some good pointers.
My queries are 1) Keith suggests a minimum gap for capilliary flow of 0.05 mms but I have no means of measuring such a gap accurately when the hole is only 8 mms diameter. Elsewhere Keith talks of a "Good rattling fit" which is probably common jargon in the UK but unknown to me in Australia. How do our members decide what is a suitable gap? Can someone explain what a "good rattling fit" means?
2) In theory I could use a high strength Loctite but I lack confidence in this because the job is for the filler caps of vintage motorcycles and will be exposed to rain and maybe petrol. If I did use a high strength locktite how tight should the parts be - drive tight, light tap or firm hand push? The material is 304 stainless. Regards, Chas
|Thread: SMOOTHING 3D PRINTS|
Sorry to have confused people with my post. Over several years I have experimented with various ideas to obtain good quality castings which require a minimum of finishing when they arrive from the foundry.
Hopefully this explanation will make everything clear (if I am lucky) There are two distinct situations:
1. Lets say I get 30 or so prints delivered from the local guy that does my 3D prints. The purpose of these prints is solely so I can send them to the foundry for casting where they take the place of a conventional wax image. I have an ongoing problem with these prints with layer lines and defects and I get round this by applying a wax to cover the imperfections. This is time consuming and the purpose of my original post was to see if there is any alternative out there, such as an aerosol wax spray that I could use.
2. The second situation is that once I am satisfied that I have got the design right and there is a market for the product, I change from 3D prints to using a permanent mould. To do this I take one of the 3D prints, spray it with automotive spray filler, sand it smooth then send this pattern to the mould maker. The mould maker makes me an aluminium /epoxy mould which then goes to the foundry. The foundry prepare waxes from this mould and carry out the casting as per usual. I get far superior stainless castings by this route.
My experience so far with 3d printing is that it is brilliant for prototype work, allowing easy changes to be made without getting expensive moulds made that turn out to be not quite suitable, but so far I have not been able to get prints of a suitably good quality for volume production.
A further experience is that I have not been successful in using PLA for the 3D prints. This might well be due to lack of expertise by the foundry but I was getting too many incomplete castings. I now get my prints done in MOLDLAY which is, I think, an American product and of undisclosed composition. This gives much better results than PLA.
Jason: Thanks for the tip about wax treatments not being compatible with making the "tree" which is how the foundry do things. I agree that silicone moulds have their own advantages, including cost but the foundry I use won't use them. Sadly there are very few foundries in Australia that will do stainless castings by lost wax and even fewer that will take on small batches like mine.
Amazing! such a quick response and so many very helpful replies
Jason: I do use exactly the technique you describe, except that the foundry I use will not accept silicone moulds. I have to get Aluminium/Epoxy moulds made. I find 3D printing just about indispensible for prototypes before committing myself to the expense of hard moulds. To avoid confusion what I do is hobby stuff to keep me mentally and physically fit at 81 years old. Any negligeable profit is quickly absorbed by new tool purchases!
Luker: Thanks very much for your reply, is Acetone only useful for ABS or does it work on other print materials? I will look into the silicone spray question but my problem is more the quality of the print surface rather than porosity. I would very much like to see a copy of your article but I don't get ME - any chance I could get a copy of the article from you? The tip of using steel wool sounds interesting!
Paul Lousick: I don't think this would work because the fillers in the primer would probably not be carried out completely with the wax when that is melted and lead to incomplete castings.
Neil: You are quite correct, it's all a question of terminology. As a retired chemist, vapour implies concentrated matter to me while what you describe would be fumes. No matter, your terminology is every bit as good as mine I shall study your link in detail as soon as I finish this post!
Adrian Johnstone: Thanks for your link. Again I will study it in detail as soon as I finish this post. I have seen prints from resin printers and they are truely of amazing quality. However the one I know about use "acrylic resins" which may not be suitable as "waxes", although they would be excellent for making silicone moulds. For me I suspect costs would be prohibitive.
Steve F: I shall certainly investigate this
Bazyle: Unfortunately the foundry are no more co-operative than they need to be but I will try to get them to run a few prints coated with PVA just to see what happens. "Just to see what happens" is the curse of the scientific mind. It can lead one into all sorts of trouble DAHIK. The choice of foundries in Australia is very limited.
My interest in 3D printing is deliberately limited (so little time, so many potential areas of interest) to buying in 3D prints that are used as “waxes” for lost wax casting in stainless steel. I use the stainless castings to make a range of handlebar levers etc for vintage and veteran motorcycles.
As bought, the prints often have minor defects and visible “layer lines” all of which can result in a failed or poor quality casting. To get round this I go over the castings with a wax product I get from the foundry. I think this is a locally-made product here in Australia and the foundry uses it to repair blow holes etc in conventionally produced wax masters before casting. This process is slow and time consuming and I want to find an alternative.
What I need is a spray-on wax that gives a thickish build on the 3D print, which I can then smooth off to give a good surface to the print.
My question is – can anyone think of such a product, maybe designed for a totally different purpose that would do this job? Aerosols of car polish wax give too thin a build to be of much use.
Some alternatives that I have already looked at are:
|Thread: Face Knurling...|
Thanks for a most interesting post. What are your views on stainless steel spokes? These seem to be popular on motorcycle restorations these days. My motorcycles are all pre-1930 and not massively powered but I still use non-stainless spokes. I don't know what type of steel they are.
|Thread: (bicycle) thread identification?|
A really interesting set of replies and very helpful. as usual Hopper and S.O.D have come up with common sense answers. Clearly it really doesn't matter a hoot for the miscellaneous small fittings on motorcycles which is what I had in mind. If the application was more demanding e.g. timing shaft nut to secure the timing pinion, then I would be sure to use matching thread forms, just as a precaution.
I really wonder just how accurate thread angles would be on el-cheapo handyman screws from Thailand or China would be anyway?
Does it make any significant difference in practice (as opposed to theoretical considerations) if a thread is 55 or 60 degrees?
If I mate a 55 degree brass thread nut with a 60 degree CEI bolt, does it really matter?
I'm thinking here of motorcycle type applications, not extreme performance situations.
|Thread: My easy solution to No More Clogged Spray Paint Rattle Cans|
A great solution that I will definitely try. My solution is less elegant but so far has worked for me, is that after clearing the nozzle by a quick press with the can inverted (which as Blue Heeler says does not work too well for long-term storage) is to push a fine wire into the spray hole and leave it there until the spray can is used again. I have kept a clapped-out wire brush for use as a fine wire donor.
|Thread: Fuel Resistant Filament|
Potentially a very interesting topic for me and a way of making floats for very obsolete carburetters. However I live in Australia and have not come across the terms rohacell or nitrophyl before. Can anyone tell me what sort of material these are?
I believe that Indian motorcycles always (?) used a float made from cork or balsa wood, covered in some sort of petrol proof lacquer - does anyone know what this lacquer was?
My knowledge and interest of motorcycles only goes to 1939 (with a special interest in New Imperials) but I thought that Amal monoblocs had nylon floats??
|Thread: BA threads|
I read and enjoyed the link provided by Peak 4, thanks Bill. Has anyone heard of the Enfield inch for rifle etc manufacture? I was told that at one time, a contractor made some parts to Enfield drawings which did not fit. The reason was that the drawings used the Enfield inch which was different to anyone else's inch
|Thread: Workshop temperature - cold|
12C is about my minimum working temperature but in this part of Australia temperatures only get that low for about two months a year and not every day is that low.Plenty of clothing covers the situation. I hate being cold (which is why I emigrated over 50 years ago) but heat and humidity don't worry me. My "stop work temperature" in summer is 42C, not so much because I am uncomfortable but because I think heat-stress could arise with dangerous consequences. Maximum temperature recorded in my workshop is 47C.
|Thread: Aldi sharpener modifications|
What is the status of the original PlasPlugs sharpener? Is it still available and from where? Approximate cost?
Rip-off versions are readily available but the reviews above are not that encouraging!
|Thread: Grumpy old men|
My pet hate is deliberate bastardisation of the language e.g. the practice of calling one partner in a homosexual relationship the husband and the other the wife. Previously the meaning of these words was plain and unambiguous .
Given that people of homosexual inclination are often intelligent, sensitive people surely they could do better than this? The feminists did a bit better when they succeeded in introducing the (phonetically ugly) term Ms.
Other than that, the repeated and unnecessary use of "like" and "you know" by the young irritates as does the practice by many young people of speaking very, and unnecessarily fast. A real curse for us oldies whose hearing is not as good as it once was.
|Thread: Removing bang in self tappers|
Thanks for this info, just what I needed. I stand in awe of your internet searching capabilities
I hope I am not taking this topic too far from the thread but these "Drive Screws" are of interest to me because they were used by Powell & Hanmer to secure their badge on motor cycle fittings, including their horns. I make replicas of these horns and have had difficulty in knowing what to buy. I have seen adverts for size 0, 1 etc but no indication anywhere of what dimensions these sizes are. Also ones that I have acquired from autojumbles are all too short or too large in diameter. Is there any convention covering the sizes of these screws or are they whatever size the manufacturer thinks will sell? Currently I use Aluminium rivets with the head diameter reduced for appearance sake and using rivets involves a whole lot of messing around
|Thread: WHY THE TANG?|
Thanks Hopper, as usual a very concise and practical answer
I have resorted to banging the taper home with a plastic hammer in the past but I did so with a bad conscience, thinking I was being brutal.
The taper holding capability of my lathe ( a 15-year old Herless) has never been anywhere near your old Drummond so it is time I got the blue out and did some checking.
Thanks also to Emgee and Speedy Builder5, I will search for longer tangs just in case I can't get passable results from my tailstock.
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