Here is a list of all the postings Buffer has made in our forums. Click on a thread name to jump to the thread.
|Thread: Advice on Resistance soldering|
Joe thanks for the info, that seems like really good advice which I will probably try. I'm not really sure why you would need a relay isolated from the mains to switch it on and off. What is wrong with just a normal foot switch, switching the power to the primary side? I'm sure as long as all the electrics on the mains side are safely concealed the only danger as far as I can see is getting burnt by the secondary side and not shocked as its an isolated transformer and only a couple of volts. or am I missing something?
Michael That is exactly the thing I had in mind. Gerald Wingrove emailed me this morning and told me he used a variable transformer on his but it has very recently died in a puff of smoke. So he is getting an American Beauty but they are very expensive.
I already have a microwave transformer and have taken out the secondary winding.
I don't know what current I need so cant answer that one I'm afraid. I am guessing a power output of 200-300 Watts.
I wanted to do this after seeing the Gas Turbine Builders Association stand at the Warwick Model Engineering show. They had a spot welder on their stand that was being demonstrated welding stainless steel. It was made from a microwave transformer. It used a timer from Maplin to control the on/off time of the weld. I have the plans for this welder from the GTBA but i would like to use this to just heat brass for soldering and not welding. Hence my question about controlling the output so I dont melt my brass.
Thanks for your advice above
Thanks. When i used the search in the top right corner it looked to me as if nothing came up but I now see it does.
I want to make a resisitance soldering unit for building my tender bodywork and other projects. I was trying to do something similar to Gerald Wingrove as described in his book. I know about using an isolation transformer and don't stick your finger on the mains etc
The advice I was looking for is what is the best or simplest method to control the primary side of the transformer in order to vary the heating on the secondary side. I have just read an old article in MEW about a band saw welder but the control method is a bit sketchy.
I know some people may be a bit reluctant to give this sort of advice as there are a lot of plonkers out here but I am not really doing anything different than making an instant heat soldering iron but with a variable heat control.
Thanks for any help.
|Thread: drilling a 20mmx 300mm Hole in cast iron|
I am going to put on progressive rifling or gain twist. Thats one reason why I want the hole drilled to the end.
I will put a progressive spiral of rod around a larger rod and then pull this through a die to spin the cutter as it comes up the tube.
Going back to your previous post, this would make a nice little model all by itself!
Its a 12.5 inch in Hurst Castle near Isle of Wight. Its got wood work lathe work, it would be great.
Thanks for the advice. I could build the barrel up over a tube then I won't have to drill my hole at all. It would just be a few fat stubby bits needing a hole. Also if I mess up something I wont scrap the entire job.
How do you chill iron
I hope this doesn't become a debate on illegal firearms. It is not going to be a working model as it will not have a vent drilled. My intent is to make a good quality scale model of a cannon on a pivoting carriage and not to make a working illegal firearm. Just because it looks like a cannon doesn't make it any more of a weapon than a piece of blocked up scaffold pipe or a bar with a hole in it. Its going to be a good quality model.
First of all thanks for all your advice. I will look for a piece of cored bar as Hopper suggests and then use the drill extension that Rod and the others have mentioned.
It is a through hole and it is for a cannon barrel. I am probably going to have a go at the type shown below.
It needs a through hole so I can put riffling in it, the breech end will then be blocked up with a screwed on cascabel. The real ones had the cascabel screwed into place also.
I have just done a quick search and drills that are too small and too short are crazy prices some over £100.
Is there any other way you know of?
Does anyone know how to drill a 20x300mm hole in cast iron when I don't have a very long drill and I cant fit that and the work between centres in the lathe anyway so it will have to be in the pilar drill.
Could I make something like a D bit or other cutter from silver steel? Would it last long enough and what shape should I use?
Has anyone extended a drill bit and if so how did you do it, was it a success?
Could I extend a blacksmith type of drill?
Thanks for any help you might be able to give, I appreciate it.
|Thread: 10 inch Mortar Scale Model|
I got the picture from a google search I think it is Fort Henry in Ontario. I have actually only seen these mortars twice. One was in the army museum in Lisbon and one in Guernsey. The drawings I made were from scaling various photos from google. There are so many different variations of the same piece that its difficult to make an exact scale model unless you visit one with a tape measure. That's why the grey block looks different as I would have copied that from a different picture.
An update on the mortar, its now finished so I have uploaded a few photos. I hope you like it!
Next will hopefully be a Victorian Rifled Muzzle Loader on a pivoting carriage.
How will he clean up the bit of barrel between the trunnions and get it as nice as the turned bits at either end?
Many thanks, I like your models a lot too.
The fillets were a real pain in the bum. As you know they have curves in awkward directions and seemed to me to be impossible to machine so I filed them. I first bored the hole for the trunnion into the fillet. I then pushed blutac onto the barrel and made a blutac filet. After carefully taking this off it gave me the shape I needed to file. It was very tricky but I did get a half decent fit in the end. They were then attached with an epoxy metal from b and q and a small amount was needed to fill some small gaps. I doubt this would be any good for you though as you are probably not intending to paint your brass model but I am going to paint mine.
If you do find a way let me know, I can only think of casting a complete barrel but thats not much help.
Having not seen nearly enough artillery models built I thought I would post a picture of my first model. Its a fairly simple scale model of a 10 inch Mortar from the Victorian era. If anyone is interested I can put up a few more pics as it progresses.
Is anyone else building this kind of thing?
|Thread: Firefly .46 crankcase|
I spotted the error with the 30mm hole and did it to the correct size but unfortunately I did not pick up the next error which is to mill the flat sides to a wall thickness of 3.75mm. I did this without giving it too much thought and guess what, it dont work with a 28.2mm hole! I am just under 2mm short now.
I am a bit miffed that this is given as a beginners engine but the description has these errors in. I know I could have worked it out from the drawing but I am the beginner they talk about and I didnt. I guess the first lesson learnt here is dont rely on someones description.
David, maybe you could print a correction each fortnight in ME and then us beginners could just build a fortnight behind and hopefully get it done without too much scrap.
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