Mini gas burner
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Dean,
Please remember, when you get your plans, I am modifying the top end of the stack, so a few of the measurements have been changed from what the plans say, namely the diameter of the top of the taper and also the diameter of the gauze disc. I have shown you how to make the d-bit, you could just mod my figures to match what you want to do. With something like that area, I don't think anything is written in stone, so you can mod it almost any way you want, as long as you don't restrict anything. As shown on the web site, and a thing I will be doing with a couple of these, Jerry even turned the tops thru 90 degrees.
Now back to this build. You may have noticed, nothing has been done with this over the last couple of days. The reason for this is that my quack has doubled my morphine dose, and my body has been getting used to it, like I have been sleeping for almost two days, broken by bouts of almost awake, good enough to surf but I am a bit unsafe to work on machinery, but if all goes well, by tomorrow I should be safe again.
Anyway, just to keep a bit of interest going, these turned up yesterday.
The 2-56 screws are what I have been waiting for, and are for use if anyone needs a US threaded jet. Very nice quality and no problems with the seller, took just over a week to get from the US to the UK by snail mail. Ebay # 130297242699
The other item is nothing to do with this post, just my magpie instinct for shiny things that will be used at a later date.
These are Bosch Rexroth linear bearings from a chappie in Slovakia, who is stripping some good bits of machinery down. These cost less than 12 squid each including postage, and if anyone knows about these things, they were a bargain. They were supposed to be used, but they are just like brand new. He has some other very nice stuff available if you are into this sort of thing and know what you are looking for. This is an ebay number for these types of items, 170439636831, and from there, you should be able to see what he has to offer. They took 10 days to get to me. Again no problems with the seller.
So maybe you might get a bit more of the machining tomorrow.
Blogs
Please remember, when you get your plans, I am modifying the top end of the stack, so a few of the measurements have been changed from what the plans say, namely the diameter of the top of the taper and also the diameter of the gauze disc. I have shown you how to make the d-bit, you could just mod my figures to match what you want to do. With something like that area, I don't think anything is written in stone, so you can mod it almost any way you want, as long as you don't restrict anything. As shown on the web site, and a thing I will be doing with a couple of these, Jerry even turned the tops thru 90 degrees.
Now back to this build. You may have noticed, nothing has been done with this over the last couple of days. The reason for this is that my quack has doubled my morphine dose, and my body has been getting used to it, like I have been sleeping for almost two days, broken by bouts of almost awake, good enough to surf but I am a bit unsafe to work on machinery, but if all goes well, by tomorrow I should be safe again.
Anyway, just to keep a bit of interest going, these turned up yesterday.
The 2-56 screws are what I have been waiting for, and are for use if anyone needs a US threaded jet. Very nice quality and no problems with the seller, took just over a week to get from the US to the UK by snail mail. Ebay # 130297242699
The other item is nothing to do with this post, just my magpie instinct for shiny things that will be used at a later date.
These are Bosch Rexroth linear bearings from a chappie in Slovakia, who is stripping some good bits of machinery down. These cost less than 12 squid each including postage, and if anyone knows about these things, they were a bargain. They were supposed to be used, but they are just like brand new. He has some other very nice stuff available if you are into this sort of thing and know what you are looking for. This is an ebay number for these types of items, 170439636831, and from there, you should be able to see what he has to offer. They took 10 days to get to me. Again no problems with the seller.
So maybe you might get a bit more of the machining tomorrow.
Blogs
Sorry to have dragged on with a post that should have finished ages ago.
Now my brain cell is in sync with my body a little better, I have managed to get a tiny bit more done today.
I went over the whole planset to work out what material I required, and to see if anything could be changed to suit what I already had.
I also redesigned the control valve to what I consider a better and easier setup for me to to make, plus the o-ring can be easily changed if needed.
Jerry shows how to make various versions of the needle valve by the use of bits out of disposable lighters., so my mods shouldn't make any difference. As mentioned before, you make it to how it says on the plans if you want to.
The body sleeve, to me, is another important part of this unit, and the 3/8" tube has a thicker wall than what it states on the plans. Maybe the one he used was from another supplier, and might be available from somewhere like K&S as standard.
I had forward planned on this, and is the reason I didn't finish off the stack before this part was made, as all these parts are reliant on the measurement of each other, and the internal measurement of my tube is what the parts will be made to.
So here is the tube in the lathe.
I know that my topslide is perfectly square to the spindle, so I can put on accurate measurements with it's leadscrew.
Saddle locked and using a 0.050" wide grooving/parting tool I faced off the end, and zeroed up the scale.
Forwards on the topslide handle by 0.800", 0.050" tool width plus 0.750" part length, the tube was parted off.
Not far off at all.
I knocked off a few more at the same settings.
I measured the internal dimension of a few of them, and they all came out the same.
So I need to prove the figure, as it is critical for all the parts to fit together correctly.
A bit of rough oversized bar was mounted in the chuck.
It was then turned down to the figure I had obtained, and the tubes fitted perfectly. I now know that if I use this figure, no sloppy fits will be made, mainly because I want the stack a tightish, but removeable fit, so that the jet can be changed easily. That is as far as I could get today, but I will show you a bit more about the drill I will hopefully be using to do the jets. I did this work before I cut these tubes up.
I have a bench magnifier, but it is a little large to get near to the drill, and I also have a set of magnifeyes, but for drilling, I need a little more mobility, not having to swing them out of the way when I require normal vision. So I bought one of these, the fifth one down, with the horseshoe shaped base.
http://rdgtools.co.uk/acatalog/MAGNIFYING_LIGHTS.html
Even though it is only 2X for the main lens, it gives very good magnification and clarity up to a good distance away.
The weighted horseshoe base was easily screwed off, and I made a much smaller ali one with four neodindinaineum rare earth magnets fitted in. I can stick it anywhere I want it on the machine, or even on the lathe or mill if I am doing tiny work.
With the led lights on (run from a battery in the glass holding head), I have a great view of the drill tip, to see how it is progressing thru the job.
Gradually getting there.
Blogs
Now my brain cell is in sync with my body a little better, I have managed to get a tiny bit more done today.
I went over the whole planset to work out what material I required, and to see if anything could be changed to suit what I already had.
I also redesigned the control valve to what I consider a better and easier setup for me to to make, plus the o-ring can be easily changed if needed.
Jerry shows how to make various versions of the needle valve by the use of bits out of disposable lighters., so my mods shouldn't make any difference. As mentioned before, you make it to how it says on the plans if you want to.
The body sleeve, to me, is another important part of this unit, and the 3/8" tube has a thicker wall than what it states on the plans. Maybe the one he used was from another supplier, and might be available from somewhere like K&S as standard.
I had forward planned on this, and is the reason I didn't finish off the stack before this part was made, as all these parts are reliant on the measurement of each other, and the internal measurement of my tube is what the parts will be made to.
So here is the tube in the lathe.
I know that my topslide is perfectly square to the spindle, so I can put on accurate measurements with it's leadscrew.
Saddle locked and using a 0.050" wide grooving/parting tool I faced off the end, and zeroed up the scale.
Forwards on the topslide handle by 0.800", 0.050" tool width plus 0.750" part length, the tube was parted off.
Not far off at all.
I knocked off a few more at the same settings.
I measured the internal dimension of a few of them, and they all came out the same.
So I need to prove the figure, as it is critical for all the parts to fit together correctly.
A bit of rough oversized bar was mounted in the chuck.
It was then turned down to the figure I had obtained, and the tubes fitted perfectly. I now know that if I use this figure, no sloppy fits will be made, mainly because I want the stack a tightish, but removeable fit, so that the jet can be changed easily. That is as far as I could get today, but I will show you a bit more about the drill I will hopefully be using to do the jets. I did this work before I cut these tubes up.
I have a bench magnifier, but it is a little large to get near to the drill, and I also have a set of magnifeyes, but for drilling, I need a little more mobility, not having to swing them out of the way when I require normal vision. So I bought one of these, the fifth one down, with the horseshoe shaped base.
http://rdgtools.co.uk/acatalog/MAGNIFYING_LIGHTS.html
Even though it is only 2X for the main lens, it gives very good magnification and clarity up to a good distance away.
The weighted horseshoe base was easily screwed off, and I made a much smaller ali one with four neodindinaineum rare earth magnets fitted in. I can stick it anywhere I want it on the machine, or even on the lathe or mill if I am doing tiny work.
With the led lights on (run from a battery in the glass holding head), I have a great view of the drill tip, to see how it is progressing thru the job.
Gradually getting there.
Blogs
Thanks for the new post, John, and glad you were doing well enough to get back in the shop.
My prints for this burner showed up yesterday afternoon. It looks like you'll have all the head scratching
stuff done before I get started, which will make it easy on me!
You may find this interesting, or even useful sometime;
After having a look at the jet that came with the prints, I noticed a concentric ring a ways out from the tiny hole in the jet. It looked very familiar. Just like clock plates look after I've pressed a new bushing into one.
The prints say he used a sapphire, but the one in my jet is not that. I'll bet a dollar to a doughnut that the "jet" that is pressed into the 2-56 screw is a KWM brand #L-56 brass clock/watch bushing. I happen to have a KWM chart here, since I do this stuff now and then, and it says an L-56 is 1.2mm thick x 1.0mm dia x 0.15mm bore. That just happens to be almost exactly 0.006". They come even smaller, and much larger. Lots of sizes, (different part #'s).
In the U.S.A., these bushings are common and cheap. About $9 per 20. I would expect them to go for even less in the U.K., since KWM bushings are made in Germany. Much closer to you than to me. There may also be a Brit version of these. There's an American version here, that uses a similar sizing system.
I realize you're making your own, and are pretty much setup to do it, but if you should need a bunch of them, these might be the ticket. Like for when you get an order for 50 of these neat little burners...
: )
Dean
My prints for this burner showed up yesterday afternoon. It looks like you'll have all the head scratching
stuff done before I get started, which will make it easy on me!
You may find this interesting, or even useful sometime;
After having a look at the jet that came with the prints, I noticed a concentric ring a ways out from the tiny hole in the jet. It looked very familiar. Just like clock plates look after I've pressed a new bushing into one.
The prints say he used a sapphire, but the one in my jet is not that. I'll bet a dollar to a doughnut that the "jet" that is pressed into the 2-56 screw is a KWM brand #L-56 brass clock/watch bushing. I happen to have a KWM chart here, since I do this stuff now and then, and it says an L-56 is 1.2mm thick x 1.0mm dia x 0.15mm bore. That just happens to be almost exactly 0.006". They come even smaller, and much larger. Lots of sizes, (different part #'s).
In the U.S.A., these bushings are common and cheap. About $9 per 20. I would expect them to go for even less in the U.K., since KWM bushings are made in Germany. Much closer to you than to me. There may also be a Brit version of these. There's an American version here, that uses a similar sizing system.
I realize you're making your own, and are pretty much setup to do it, but if you should need a bunch of them, these might be the ticket. Like for when you get an order for 50 of these neat little burners...
: )
Dean
Dean,
Making the jets with a pivot jewel seems even worse to me than trying to drill one, but again, if you are used to working with that sort of thing, then there is nothing to stop you going down that route, and it is another method mentioned by Jerry in the plans.
I was hoping that by the time this post is finished, it might encourage a few people to have a go for themselves, just as you will be doing, and also show that the plans aren't the be all and end all, just a guide, which you can alter to suit whatever you have in your shop.
These burners which I am making are for my own use mainly, but I was going to make a few extras of the jets for anyone who thinks they aren't up to making them. But by the time I am finished, all the little holding fixtures and cutters will be there if I need to knock out a few more. Unless of course, someone comes up with a lucrative contract.
John
Making the jets with a pivot jewel seems even worse to me than trying to drill one, but again, if you are used to working with that sort of thing, then there is nothing to stop you going down that route, and it is another method mentioned by Jerry in the plans.
I was hoping that by the time this post is finished, it might encourage a few people to have a go for themselves, just as you will be doing, and also show that the plans aren't the be all and end all, just a guide, which you can alter to suit whatever you have in your shop.
These burners which I am making are for my own use mainly, but I was going to make a few extras of the jets for anyone who thinks they aren't up to making them. But by the time I am finished, all the little holding fixtures and cutters will be there if I need to knock out a few more. Unless of course, someone comes up with a lucrative contract.
John
Hi John;
I didn't mean to sound like I was trying to convince you to do it another way with what I wrote about the brass bushings. Like I said, I realize you are set up to drill your own.
Please carry on. I read all your threads with high hopes of learning new things.
Dean
I didn't mean to sound like I was trying to convince you to do it another way with what I wrote about the brass bushings. Like I said, I realize you are set up to drill your own.
Please carry on. I read all your threads with high hopes of learning new things.
Dean
No Dean, it was perfectly fine.
The more ways to do something, the better in my opinion. It gives the viewers more choice with what they have in their shop.
The plans are a little confusing to start with, because of the extra ways of doing things Jerry added. But once you disregard those bits, it is a very simple build, just that a few techniques are needed, and that is hopefully what I am showing.
Here is a drawing I got from my archive, and it gives you another choice for making the pressure regulator. You would need to make the threads for the can adapter different if they are not the same as the UK ones. I have just got to get the 1mm neoprene for the diaphragm.
John
View attachment GasValveAndRegulator.pdf
The more ways to do something, the better in my opinion. It gives the viewers more choice with what they have in their shop.
The plans are a little confusing to start with, because of the extra ways of doing things Jerry added. But once you disregard those bits, it is a very simple build, just that a few techniques are needed, and that is hopefully what I am showing.
Here is a drawing I got from my archive, and it gives you another choice for making the pressure regulator. You would need to make the threads for the can adapter different if they are not the same as the UK ones. I have just got to get the 1mm neoprene for the diaphragm.
John
View attachment GasValveAndRegulator.pdf
A bit more added to this overly long post. This time I am finishing off the body sleeve.
If you remember on the last post, I had used a bit of brass bar to verify the internal fit of the tube I am now working on. I took that, and turned a little more off it so that the tube was just a little longer than the turned down bit. If you look carefully, right next to the shoulder, I went deeper with the lathe tool and formed an undercut. That will allow the tube to sit right up to the shoulder. If I hadn't have done that, the small radius imparted to the internal corner by the cutter tip would be liable to hold the tube away from the shoulder.
The end was drilled and power tapped for a small screw.
By the use of an oversized washer, the tubes can now be safely gripped onto this holding mandrel.
There are a few ways that this next bit could have been done, with the RT sitting upright, the ideal would have been using my spindex, but because I haven't got full strength back in my fingers yet to manhandle them, I had to settle on my 5C square block and the vice back stop.
With the block pushed back to the stop and down onto the vice internal base, it was an easy job to centre the tube and find the position of the datum shoulder (the very end of the tube).
It was easy then to backstep to the drill position, and using a good quality drill, go all the way thru the job. Turn the block thru 90 degs, and repeat. Remove tube, put another one on.
In next to no time, they were all drilled.
The first one was a bit tight to get off because of the burrs thrown up on the mandrel. But once they were cleaned off with a bit of emery, everything went on and off with no problems.
A large hole now needed to be cut at 45 degrees to these ones I had just cut. So a piece of close fitting bar thru the mandrel (I used a transfer punch), the collet was loosened and the mandrel turned thru the required angle. This angle isn't super critical, but the distance between the big and small holes is. I just used my little digi angle gauge, but a standard protractor would get you plenty close enough.
Because I had been playing about with the mandrel, the datum for the shoulder had to be refound and the position of the large hole clocked in.
A sleeve put on the mandrel, a drill bit thru the original holes to get the sleeve in the correct rotational position then all tightened up. A very sharp centre cutting end mill was then used to just cut thru the tube and slightly into the mandrel. Turn thru 180 degs and repeat for the other side.
Again, things done in no time at all.
All these little bits and cutters that I am making will be put in a box and marked up, they will come in real handy when I want to make some more of these burners.
Blogs
If you remember on the last post, I had used a bit of brass bar to verify the internal fit of the tube I am now working on. I took that, and turned a little more off it so that the tube was just a little longer than the turned down bit. If you look carefully, right next to the shoulder, I went deeper with the lathe tool and formed an undercut. That will allow the tube to sit right up to the shoulder. If I hadn't have done that, the small radius imparted to the internal corner by the cutter tip would be liable to hold the tube away from the shoulder.
The end was drilled and power tapped for a small screw.
By the use of an oversized washer, the tubes can now be safely gripped onto this holding mandrel.
There are a few ways that this next bit could have been done, with the RT sitting upright, the ideal would have been using my spindex, but because I haven't got full strength back in my fingers yet to manhandle them, I had to settle on my 5C square block and the vice back stop.
With the block pushed back to the stop and down onto the vice internal base, it was an easy job to centre the tube and find the position of the datum shoulder (the very end of the tube).
It was easy then to backstep to the drill position, and using a good quality drill, go all the way thru the job. Turn the block thru 90 degs, and repeat. Remove tube, put another one on.
In next to no time, they were all drilled.
The first one was a bit tight to get off because of the burrs thrown up on the mandrel. But once they were cleaned off with a bit of emery, everything went on and off with no problems.
A large hole now needed to be cut at 45 degrees to these ones I had just cut. So a piece of close fitting bar thru the mandrel (I used a transfer punch), the collet was loosened and the mandrel turned thru the required angle. This angle isn't super critical, but the distance between the big and small holes is. I just used my little digi angle gauge, but a standard protractor would get you plenty close enough.
Because I had been playing about with the mandrel, the datum for the shoulder had to be refound and the position of the large hole clocked in.
A sleeve put on the mandrel, a drill bit thru the original holes to get the sleeve in the correct rotational position then all tightened up. A very sharp centre cutting end mill was then used to just cut thru the tube and slightly into the mandrel. Turn thru 180 degs and repeat for the other side.
Again, things done in no time at all.
All these little bits and cutters that I am making will be put in a box and marked up, they will come in real handy when I want to make some more of these burners.
Blogs
Sorry it is taking so long gents, but when you can only work in ten minute bursts, even a small job becomes a major one.
So this time, I am making the jet and control valve holder. As far as I am concerned, the jet part is the most critical bit, because it not only has to be gas tight, it also has to be totally square to the main stack, otherwise the gas plume will be fired off to one side and maybe not burn correctly.
I started off by turning some stock down to be a snug sliding fit inside the body sleeve, and parted off to basic length. There is no mention, as far as I can recollect, of how all these bits are joined together, so I have decided to do some very fine silver soldering on mine, and that will require a small gap to allow for the capillary action of the silver solder and flux.
The holders were faced off each end to bring them to spot on length. Then each end was spot drilled. It didn't really need both ends doing, but with this build being so small, even having the base mounting screw slightly off centre will make the assembly look badly made.
On just the jet end, a chamfer is put onto the part. This is a certain size, as when assembled, this part extends slightly past the air inlet holes in the body sleeve. This chamfer allows the free flow of air from the holes to the jet area.
Each end was drilled to the correct size for tapping for my 8BA sized screws. For the drawing version, you would need to drill for 2-56 threading.
The holes didn't meet in the middle, they were drilled just deep enough to penetrate into the cross drilling area.
And this is where the cross drilling starts.
First off, by using my centre finder and a parallel clamped in the vice, I got the chuck spot on centre of the part diameter.
Now this is where things can get tricky. There is not much to grip on each end of the part for drilling the large cross hole. So I will show you how I got around it.
I will just mention now that you could hold the part across the vice, resting on parallels, but for a quantity amount, I didn't want to risk having the part not square across the jaws, hence the way I did mine. Just me being paranoid.
I am lucky in that I have some 3" long parallels, and by stacking them up, I could get to the height I wanted.
I put a strip of double sided tape across each pair, then clamped the pairs into the vice to leave the correct gap between them. All four were stuck to the fixed jaw, so that they won't move out of position.
The part was rested onto the parallels, equally, either side of the gap, with the jet end away from the backstop.
Then the back stop was brought into position, so that every part should end up in the same place each time.
With everything tightened up, I took a reading off the non jet end of the part, and positioned the chuck in the correct position for drilling.
The part was removed and the drill was checked for clearance as it went into the parallel area. It looks tight, but it isn't really, just a hoptical dillusion.
Part in position, and a fairly large spot drill put in. Because I am going thru in one hit, there is no way I want the large drill bit to wander as it goes down past those curved sides.
The drill is 1/64" smaller than the stated diameter. This is a reaming allowance for after assembly with the body sleeve.
I took it steady as it went thru, especially as it went past midway, where the two end drillings were. I didn't want to have an oversized hole at this late stage.
As it was, no gremlins appeared, and everything went very smoothly.
So back onto the lathe.
I broke out my mini tapping tool and power cut an 8BA thread into each end of each part.
After the first one was cut, I tried the screws that are to become the jets, just to make sure they were a good, non sloppy fit.
This shot also shows up a problem that normally happens with commercial screws. They just never get the threads right up to under the head, so an allowance has to be calculated to counteract the hold off gap that would be created if the screw and hole were left as they were. I usually use a length of 1.5 times the thread pitch (just roughly). For my 8BA threads, 0.025" will be fine.
So using a 3/32" milling cutter (just a little larger than the OD of the threads), I touched on, and then cut in the required amount.
As you can now see, the screw now goes all the way in, and I reckon, the jet will not require a sealing washer because of the good fit of the screw under the head and in the threads.
That's as far as I have got with the build, but because I was asked about my power tapping tool, I will show you that you don't have to spend big bucks to make tooling.
On the LHS you can see a commercial mini tap wrench, I bought this hundreds of years ago, and it is still going strong, maybe because it cost an arm and two legs back then, and I still think they are pricey now.
On the RHS is the way I got one for making my mini power tapper.
If you notice, it is part of a set of real cheapo pin vices. The commercial one has a square set to the jaws, but if you mount your tiny tap with the corners into the jaw slots, it clamps up just as well, and runs perfectly true.
The knurled part was turned down until the knurl was just gone, then the shaft was measured. An old large bolt was turned to the shape of the holder you see. I had it that shape so that it cannot be pushed right back into the chuck jaws, and maybe cause damage if something broke and the holder had a backwards knock.
A hole was drilled and reamed thru it, just smaller than the shaft on the modified pin vice.
Then the pin vice shaft was turned down until it was a nice snug sliding fit in the hole. A bit of 1/8" silver steel was loctited into a cross drilled hole.
Total cost, apart from a bit of time, about 4 or 5 bucks.
Slowly but surely, we are getting there.
Blogs
So this time, I am making the jet and control valve holder. As far as I am concerned, the jet part is the most critical bit, because it not only has to be gas tight, it also has to be totally square to the main stack, otherwise the gas plume will be fired off to one side and maybe not burn correctly.
I started off by turning some stock down to be a snug sliding fit inside the body sleeve, and parted off to basic length. There is no mention, as far as I can recollect, of how all these bits are joined together, so I have decided to do some very fine silver soldering on mine, and that will require a small gap to allow for the capillary action of the silver solder and flux.
The holders were faced off each end to bring them to spot on length. Then each end was spot drilled. It didn't really need both ends doing, but with this build being so small, even having the base mounting screw slightly off centre will make the assembly look badly made.
On just the jet end, a chamfer is put onto the part. This is a certain size, as when assembled, this part extends slightly past the air inlet holes in the body sleeve. This chamfer allows the free flow of air from the holes to the jet area.
Each end was drilled to the correct size for tapping for my 8BA sized screws. For the drawing version, you would need to drill for 2-56 threading.
The holes didn't meet in the middle, they were drilled just deep enough to penetrate into the cross drilling area.
And this is where the cross drilling starts.
First off, by using my centre finder and a parallel clamped in the vice, I got the chuck spot on centre of the part diameter.
Now this is where things can get tricky. There is not much to grip on each end of the part for drilling the large cross hole. So I will show you how I got around it.
I will just mention now that you could hold the part across the vice, resting on parallels, but for a quantity amount, I didn't want to risk having the part not square across the jaws, hence the way I did mine. Just me being paranoid.
I am lucky in that I have some 3" long parallels, and by stacking them up, I could get to the height I wanted.
I put a strip of double sided tape across each pair, then clamped the pairs into the vice to leave the correct gap between them. All four were stuck to the fixed jaw, so that they won't move out of position.
The part was rested onto the parallels, equally, either side of the gap, with the jet end away from the backstop.
Then the back stop was brought into position, so that every part should end up in the same place each time.
With everything tightened up, I took a reading off the non jet end of the part, and positioned the chuck in the correct position for drilling.
The part was removed and the drill was checked for clearance as it went into the parallel area. It looks tight, but it isn't really, just a hoptical dillusion.
Part in position, and a fairly large spot drill put in. Because I am going thru in one hit, there is no way I want the large drill bit to wander as it goes down past those curved sides.
The drill is 1/64" smaller than the stated diameter. This is a reaming allowance for after assembly with the body sleeve.
I took it steady as it went thru, especially as it went past midway, where the two end drillings were. I didn't want to have an oversized hole at this late stage.
As it was, no gremlins appeared, and everything went very smoothly.
So back onto the lathe.
I broke out my mini tapping tool and power cut an 8BA thread into each end of each part.
After the first one was cut, I tried the screws that are to become the jets, just to make sure they were a good, non sloppy fit.
This shot also shows up a problem that normally happens with commercial screws. They just never get the threads right up to under the head, so an allowance has to be calculated to counteract the hold off gap that would be created if the screw and hole were left as they were. I usually use a length of 1.5 times the thread pitch (just roughly). For my 8BA threads, 0.025" will be fine.
So using a 3/32" milling cutter (just a little larger than the OD of the threads), I touched on, and then cut in the required amount.
As you can now see, the screw now goes all the way in, and I reckon, the jet will not require a sealing washer because of the good fit of the screw under the head and in the threads.
That's as far as I have got with the build, but because I was asked about my power tapping tool, I will show you that you don't have to spend big bucks to make tooling.
On the LHS you can see a commercial mini tap wrench, I bought this hundreds of years ago, and it is still going strong, maybe because it cost an arm and two legs back then, and I still think they are pricey now.
On the RHS is the way I got one for making my mini power tapper.
If you notice, it is part of a set of real cheapo pin vices. The commercial one has a square set to the jaws, but if you mount your tiny tap with the corners into the jaw slots, it clamps up just as well, and runs perfectly true.
The knurled part was turned down until the knurl was just gone, then the shaft was measured. An old large bolt was turned to the shape of the holder you see. I had it that shape so that it cannot be pushed right back into the chuck jaws, and maybe cause damage if something broke and the holder had a backwards knock.
A hole was drilled and reamed thru it, just smaller than the shaft on the modified pin vice.
Then the pin vice shaft was turned down until it was a nice snug sliding fit in the hole. A bit of 1/8" silver steel was loctited into a cross drilled hole.
Total cost, apart from a bit of time, about 4 or 5 bucks.
Slowly but surely, we are getting there.
Blogs
I hope it is Steve, lots of little techniques to be used.
But I am sure, now that I have got this far, maybe not the jet, but all the rest is well within the scope of the layman who can work to fairly fine tolerances and take their time on getting a good fit.
I can't wait to see how my twin licker will run on them. It ran fairly well when I bodged up a couple of gas burners when I first made it, but because they were so dirty running, the engine clogged up. Supposedly, these don't suffer from that problem.
John
But I am sure, now that I have got this far, maybe not the jet, but all the rest is well within the scope of the layman who can work to fairly fine tolerances and take their time on getting a good fit.
I can't wait to see how my twin licker will run on them. It ran fairly well when I bodged up a couple of gas burners when I first made it, but because they were so dirty running, the engine clogged up. Supposedly, these don't suffer from that problem.
John
This has been nagging me for hours.
Having just reread my post, it looks like I did one cut at the wrong time.
If I had left the chamfer at the jet end until the second lathe stage, just before I tapped the jet thread, the part would have been a lot easier to hold on the mill and it wouldn't have been endways critical.
I normally do a machining routine first, to show up any holding problems. But because I thought it was such an easy part to make, I didn't, and made life difficult for myself.
Next time, I will make sure I do.
Blogs
Having just reread my post, it looks like I did one cut at the wrong time.
If I had left the chamfer at the jet end until the second lathe stage, just before I tapped the jet thread, the part would have been a lot easier to hold on the mill and it wouldn't have been endways critical.
I normally do a machining routine first, to show up any holding problems. But because I thought it was such an easy part to make, I didn't, and made life difficult for myself.
Next time, I will make sure I do.
Blogs
I managed to get a little further with this project, not a lot, but enough to make up a post.
Before I start to silver solder bits together, I want to machine the pushing together parts while the metal is still hard. This is because for a few weeks after soldering, some of the metal parts will be softened by heating, They should age harden a little while other bits are made.
So using a razor sharp HSS tool, the bottom end of the stack was brought down to size to be a push fit inside the body sleeve, to the length stated on the plan. The reason for the HSS tool is that the carbide tipped ones that I normally use have a small radius on the tip, and so the two parts won't mate together tightly because the radius on the machined bit will hold them apart.
A nice tight and close fit.
Now we are ready to start the first silver solder assembly. The jet holders will be inserted into the end until the big holes line up.
You can see in this shot how small this unit is. 1.75" long, without the base.
If you have made these bits to plan, you should find that when the main holes are in line, there is a recess in the bottom of the unit. Jerry must have done this so that when it is mounted onto a base, it will pull down nice and tight onto the tube edge and so form a neat joint.
I am going to use that recess to my advantage, to hide the silver solder joint in there.
All the bits were assembled, and in each recess, I run a bit of liquefied flux (flux+water) around the inside edge, and then placed a half moon shaped bit of silver solder wire in there as well, pushed up to the outer edge.
Ready for soldering.
A few seconds later, after a flash over with a big burner, all have a perfectly formed fillet joint with no runout of solder onto the outside faces. They were then dropped into a citric acid bath for ten minutes, just to get rid of excess flux residue.
This is after they came out of the acid bath. Notice how neat the fillets are, and how little flux has gone onto the outer faces.
I have no idea why people have so much trouble with silver soldering, it really is as easy as I have shown it. The flux is the secret, I have used the Tenacity range for many years now, it is now up to Tenacity #5, and is really designed for stainless, but is perfect for almost all metals as it doesn't suffer the flux burnout as most others do.
I reamed thru the big cross hole, which tidied everything up, and cleaned off the rest of the flux with a bit of wire wool.
It is now ready for having the gas control valve making, which I should be doing in the next post.
Blogs
Before I start to silver solder bits together, I want to machine the pushing together parts while the metal is still hard. This is because for a few weeks after soldering, some of the metal parts will be softened by heating, They should age harden a little while other bits are made.
So using a razor sharp HSS tool, the bottom end of the stack was brought down to size to be a push fit inside the body sleeve, to the length stated on the plan. The reason for the HSS tool is that the carbide tipped ones that I normally use have a small radius on the tip, and so the two parts won't mate together tightly because the radius on the machined bit will hold them apart.
A nice tight and close fit.
Now we are ready to start the first silver solder assembly. The jet holders will be inserted into the end until the big holes line up.
You can see in this shot how small this unit is. 1.75" long, without the base.
If you have made these bits to plan, you should find that when the main holes are in line, there is a recess in the bottom of the unit. Jerry must have done this so that when it is mounted onto a base, it will pull down nice and tight onto the tube edge and so form a neat joint.
I am going to use that recess to my advantage, to hide the silver solder joint in there.
All the bits were assembled, and in each recess, I run a bit of liquefied flux (flux+water) around the inside edge, and then placed a half moon shaped bit of silver solder wire in there as well, pushed up to the outer edge.
Ready for soldering.
A few seconds later, after a flash over with a big burner, all have a perfectly formed fillet joint with no runout of solder onto the outside faces. They were then dropped into a citric acid bath for ten minutes, just to get rid of excess flux residue.
This is after they came out of the acid bath. Notice how neat the fillets are, and how little flux has gone onto the outer faces.
I have no idea why people have so much trouble with silver soldering, it really is as easy as I have shown it. The flux is the secret, I have used the Tenacity range for many years now, it is now up to Tenacity #5, and is really designed for stainless, but is perfect for almost all metals as it doesn't suffer the flux burnout as most others do.
I reamed thru the big cross hole, which tidied everything up, and cleaned off the rest of the flux with a bit of wire wool.
It is now ready for having the gas control valve making, which I should be doing in the next post.
Blogs
spuddevans
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Great writeup John, while I have no plans to make a mini gas burner, there is still a lot to learn that can be applied to other situations, so thanks for showing your process and explaining it so clearly.
That is so true. For folks who have never silver-soldered, just try the method that John shows here. Up to relatively recently I had never silver-soldered, but sticking to the method John explained in the paddleduck engine plans meant that after just one practice joint ( that turned out ok, amazingly to me ) I have been able to solder up a number of joints with only one joint not perfect ( but that was easily fixed ).
This really does open up so many engineering "doors" so it is well worth trying it.
Sorry about the slightly off-topic rant, back to your usual programming.
Tim
Blogwitch said:
That is so true. For folks who have never silver-soldered, just try the method that John shows here. Up to relatively recently I had never silver-soldered, but sticking to the method John explained in the paddleduck engine plans meant that after just one practice joint ( that turned out ok, amazingly to me ) I have been able to solder up a number of joints with only one joint not perfect ( but that was easily fixed ).
This really does open up so many engineering "doors" so it is well worth trying it.
Sorry about the slightly off-topic rant, back to your usual programming.
Tim
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