Hi,
This is an ongoing project started before Covid and everything that could go wrong and everything that couldn't go wrong went wrong. In spite of this I've kept having a go time permitting and now I've got a fully working machine. There are many micro wave transformer projects on YouTube and this is where I got the basic idea. A friend who owns a business uses TC tipped tooling in long handles to trim metal being spun manually; the TC tips receive a terrific beating and cheap tooling simply isn't up to the job. He has bought a number of top quality TC blanks at 10mm square x 3mm thick.
During one of my visits before Covid I was shown an attempt at brazing one of these tips using oxy/acetylene equipment which had failed in use and was asked if I had any ideas. Closely inspecting the failed tool it was evident the cause was a "dry joint". I discussed this with the guy who had brazed the tip and the method he used was standard procedure but as the tip and tool heated to cherry red he had pressed down on the tip with a screwdriver to bring the tip into close contact with the tool and I think this is only thing he did that could have accounted for the dry joint. I left with 22 TC tips and a length of 10mm square BMS bar stock to experiment with; these tools are only about 65mm long being inserts into the long handle.
Back home in the workshop I could now decide what to attempt; I had been informed the tips could simply be "planted" on the tool end with braze but I thought a better job could be achieved by forming a land to accept the tip so not having a mill and not wanting to bother using the lathe with an end mill chucked I cut the bar into short lengths then used a hacksaw and engineers files to create the land on each; I can file flat to a thou and the job was good arm exercise.
I have Sifbronze brazing flux and correct brazing rods but I also wondered if I could use brass shim stock so bought a small sheet of brass through eBay; my plan was to split the TC tips into two batches as an experiment; one batch using the brazing rod the other batch using the brass shim.
This work was extremely slow with all kinds of problems getting in my way including all the Covid problems trying to obtain materials and being in a Covid hotspot for well over a year meant only necessary journies from home mostly shopping so I started to lose much of my interest as time passed by.
Eventually I resumed work and at first tried using a big paraffin blow lamp to heat the tool but this failed miserably the flame not hot enough however using my Mapp Gas cartidge torch struggled but did heat to cherry red allowing the braze to flow after fluxing; I set the tool up in the big engineering vice and used a third hand just to keep the TC tip on position as I applied heat adding filler rod. Before doing this however I was fully aware of the dry joint problem and to simply copy the method would yield the same result in failure so I needed to resolve this and the solution came to me at around 3am whilst in bed fully awake in peace and quiet when I could concentrate without constant interruptions or demands on my time. I wondered if I could simply center pop the land using a hammer and punch knowing to center pop metal always throws up a round low burr?
One way to find out was to try the idea out never having seen this done before. I added three light center pops to a land and set everything up; as I say the blowlamp wasn't hot enough but the torch was; I heated the filler rod plunging it into the flux and it took a great deal of heat to bring the tool to cherry red but once the filler rod was seen to run the joint I could dispence with the heat. It looked good so I did the first batch using filler rod and due to Covid restrictions posted the batch to my friend who in turn quaranteed the batch for three days. A few days later an email was received saying he was delighted with the tooling it standing up well.
Having succeeded with brazing rod next was the brass shim; once again I center popped the land when I say center popped I didn't clout the punch only wanting to throw up a small burr ring; 10mm square shims were cut but now I formed a flux paste adding Sifbronze flux powder to water then brushing this to all surfaces of the joint; this too proved a success when the tools were tested so now I had the solution to the problem of the dry joint; by now I'd used quite a lot of expensive Mapp gas and wanted a way of heating the tools costing less then I remembered the "Metal melter" video on YouTube;
Having now added the run up to my brazing machine I'll add pictures thus far and continue in a second post with the brazing machine story; I keep running out of time but hope it's interesting so far.
Kind regards, Colin.
BMS tool blanks. Top row show lands added and a completed tool.
Roughing out the lands using a hacksaw which was time consuming followed by hand filing.
A batch roughed out.
Sorry about the poor picture but here the center pop has added indents throwing up a shallow burr.
Ready for brazing.
Cleanliness is very important indeed. Left shows the raw TC blank; right shows after rubbing on a Trend diamond hone with water as lubricant.
Labourious work but highly necessary; I enjoy this kind of project when I have rare workshop time to potter around.
The edges too were honed clean.
Here a brass shim has been placed in position; paste Sifbronze flux was added first then more flux added before adding the TC tip making a sandwich. I'm hopelessly colour blind so it didn't come as a surprise to find out there was a film of plastic on the brass sheet the hard way once heat was applied; I live and learn.
A third hand seen gently holding the tip in position and the picture taken just after the heat had been withdrawn. Brazed tooling can be seen these just having been done still needing fettling to tidy them up. Brazing with the torch worked well but I wanted a better method; The initial problem was now fully sorted and my friend was happy to now have a stock of tooling but I now wanted to experiment and this is where it really became a real pain as things went wrong all out of my control. Hopefully the next post showing the new brazing machine will prove more interesting. I'm out of time again; as usual I've got a more pressing job to do this time replacing a double glazed unit to the kitchen I've already replaced five lots of glazing; 20 years retired and still can't play out. My friend has grinding facilities and has a mill so any future tooling will have the lands added on the mill saving me lots of arm ache; Covid restrictions are being lifted so with luck I can visit my friend once again rather than commumicate by email.
This is an ongoing project started before Covid and everything that could go wrong and everything that couldn't go wrong went wrong. In spite of this I've kept having a go time permitting and now I've got a fully working machine. There are many micro wave transformer projects on YouTube and this is where I got the basic idea. A friend who owns a business uses TC tipped tooling in long handles to trim metal being spun manually; the TC tips receive a terrific beating and cheap tooling simply isn't up to the job. He has bought a number of top quality TC blanks at 10mm square x 3mm thick.
During one of my visits before Covid I was shown an attempt at brazing one of these tips using oxy/acetylene equipment which had failed in use and was asked if I had any ideas. Closely inspecting the failed tool it was evident the cause was a "dry joint". I discussed this with the guy who had brazed the tip and the method he used was standard procedure but as the tip and tool heated to cherry red he had pressed down on the tip with a screwdriver to bring the tip into close contact with the tool and I think this is only thing he did that could have accounted for the dry joint. I left with 22 TC tips and a length of 10mm square BMS bar stock to experiment with; these tools are only about 65mm long being inserts into the long handle.
Back home in the workshop I could now decide what to attempt; I had been informed the tips could simply be "planted" on the tool end with braze but I thought a better job could be achieved by forming a land to accept the tip so not having a mill and not wanting to bother using the lathe with an end mill chucked I cut the bar into short lengths then used a hacksaw and engineers files to create the land on each; I can file flat to a thou and the job was good arm exercise.
I have Sifbronze brazing flux and correct brazing rods but I also wondered if I could use brass shim stock so bought a small sheet of brass through eBay; my plan was to split the TC tips into two batches as an experiment; one batch using the brazing rod the other batch using the brass shim.
This work was extremely slow with all kinds of problems getting in my way including all the Covid problems trying to obtain materials and being in a Covid hotspot for well over a year meant only necessary journies from home mostly shopping so I started to lose much of my interest as time passed by.
Eventually I resumed work and at first tried using a big paraffin blow lamp to heat the tool but this failed miserably the flame not hot enough however using my Mapp Gas cartidge torch struggled but did heat to cherry red allowing the braze to flow after fluxing; I set the tool up in the big engineering vice and used a third hand just to keep the TC tip on position as I applied heat adding filler rod. Before doing this however I was fully aware of the dry joint problem and to simply copy the method would yield the same result in failure so I needed to resolve this and the solution came to me at around 3am whilst in bed fully awake in peace and quiet when I could concentrate without constant interruptions or demands on my time. I wondered if I could simply center pop the land using a hammer and punch knowing to center pop metal always throws up a round low burr?
One way to find out was to try the idea out never having seen this done before. I added three light center pops to a land and set everything up; as I say the blowlamp wasn't hot enough but the torch was; I heated the filler rod plunging it into the flux and it took a great deal of heat to bring the tool to cherry red but once the filler rod was seen to run the joint I could dispence with the heat. It looked good so I did the first batch using filler rod and due to Covid restrictions posted the batch to my friend who in turn quaranteed the batch for three days. A few days later an email was received saying he was delighted with the tooling it standing up well.
Having succeeded with brazing rod next was the brass shim; once again I center popped the land when I say center popped I didn't clout the punch only wanting to throw up a small burr ring; 10mm square shims were cut but now I formed a flux paste adding Sifbronze flux powder to water then brushing this to all surfaces of the joint; this too proved a success when the tools were tested so now I had the solution to the problem of the dry joint; by now I'd used quite a lot of expensive Mapp gas and wanted a way of heating the tools costing less then I remembered the "Metal melter" video on YouTube;
Having now added the run up to my brazing machine I'll add pictures thus far and continue in a second post with the brazing machine story; I keep running out of time but hope it's interesting so far.
Kind regards, Colin.
BMS tool blanks. Top row show lands added and a completed tool.
Roughing out the lands using a hacksaw which was time consuming followed by hand filing.
A batch roughed out.
Sorry about the poor picture but here the center pop has added indents throwing up a shallow burr.
Ready for brazing.
Cleanliness is very important indeed. Left shows the raw TC blank; right shows after rubbing on a Trend diamond hone with water as lubricant.
Labourious work but highly necessary; I enjoy this kind of project when I have rare workshop time to potter around.
The edges too were honed clean.
Here a brass shim has been placed in position; paste Sifbronze flux was added first then more flux added before adding the TC tip making a sandwich. I'm hopelessly colour blind so it didn't come as a surprise to find out there was a film of plastic on the brass sheet the hard way once heat was applied; I live and learn.
A third hand seen gently holding the tip in position and the picture taken just after the heat had been withdrawn. Brazed tooling can be seen these just having been done still needing fettling to tidy them up. Brazing with the torch worked well but I wanted a better method; The initial problem was now fully sorted and my friend was happy to now have a stock of tooling but I now wanted to experiment and this is where it really became a real pain as things went wrong all out of my control. Hopefully the next post showing the new brazing machine will prove more interesting. I'm out of time again; as usual I've got a more pressing job to do this time replacing a double glazed unit to the kitchen I've already replaced five lots of glazing; 20 years retired and still can't play out. My friend has grinding facilities and has a mill so any future tooling will have the lands added on the mill saving me lots of arm ache; Covid restrictions are being lifted so with luck I can visit my friend once again rather than commumicate by email.