Great to see another CVA No.79 Jig Borer/Mill still doing the job it was made to do over 70 years ago. Mine is in daily use and has been since I bought it 40 years ago.
Mine is perfect for the low ceiling of the workshop and is in great condition, very accurate and working well. I have been working on power down feed and crossfeed, which you may see in some video, that is still work in progress.
Excellent fit insert to head and rose to insert, many variables there a sure sign of someone who knows what they're doing! Excellent work many thanks for posting, cheers Jim.
Thanks Rahul. I've not forgotten you, I'm still trying to find someone interested in helping with your project, it may take a little while yet. Be back to you when I have news. regards and best wishes, Ade.
My local engineer always pins the insert. It's never failed yet. I find the bronze lock rings stay in the head far better than the standard rings, which tend to loosen on longer journeys. I don't recommend using the locking tabs with the lock rings as these don't stop the lock ring loosening, but allow them to be loosen just enough to damage the threads.
I owned a 1973 Interstate and could never keep the pipes tight. Did have the ports sleeved with bronze but the inserts eventually pulled out. Recently I saw a different method of repair on a Roadster. It had spiggots welded into the ports with Triumph style externaly clamped pipes fitted. The owner said he has had no trouble with the pipes since doing this repair. Can't comment on the long term success as I havn't seen the bike again.
Interesting way of doing a repair.I dare say there are several ways to improve the original pipe clamping method, problem is in 2019 most (not all) folks wanting a repair want to preserve the original 'look' of the bike, hence finding 'invisible' ways of doing the repair, not necessarily better. Thanks for the comment, Ade.
@@AGEngineeringAgreed, definately not for a show bike. Also possible distortion of the head from welding, extra heat transfer into head while running and possibly fatigue cracking of the spiggots at the pipe junction as there would only be about 6mm wall at that point. Still much less machining for a cheaper repair.
Yes, my Commando was a pain in the neck too. I made up oversized exhaust rings but the design puts way too much stress just there, especially on the Commando where the engine is allowed to dance around.
The reason commandos have issues is usually down to the amount of movement in the isolastics. This can be especially bad when aftermarket, ridgedly mounted silencers are fitted.
When in Machine Shop Operations schooling ('86-'87), this was a project the instructor Allowed me to do. We decided to machine a single point threaded set of sleeves, these being SLIGHTLY oversize . This required sticking them in the freezer and installing them immediately. I was a little slow with the one but managed to pound it the rest of the way home. Then, it was sent to Bobby the weld instructor(Sweetheart of a guy). He said he had a little difficulty welding them , and wondered if the alloy didn't contain a little Magnesium or something. Too many years ago.
Thanks for watching and commenting, please take a look through the comments on the various exhaust thread repair videos I have posted, there are many discussions on this controversial issue 😂
Hi , not many use the 30 degree ½ included angle any more , compound set straight and just zero the compound slide and add clearance as required. Cheers
@@AGEngineering Myself and a family member both have Early Commandos (1971, 1972 & 1973) - would you consider these bikes "newer" and have a 60 degree thread in the exhaust port/nuts? Your help is appreciated! I will look to see if I can find my thread gauges as well.
Yes commando, atlas, later 650ss would be 60 degree. All the usual suppliers of new exhaust nuts/rings supply 60 degree, and usually they are not the greatest quality so are 'sloppy' enough to fit the worn original threads of earlier 55 degree head threads anyway.
It's quite difficult to determine the difference between 55 and 60 with thread gauges, I have had new and old nuts on my shadowgraph to measure thread angle.
The gap probably isn't a problem, and in fact will lock the ring in once the engine has been run a few miles. Modern shotguns use screwed in chokes with fine threads, and unless they are taken out and cleaned, the gasses enter any gaps and make them practically immovable.
I think you're going to lose must of the strength of the Loctite 680 at exhaust port temperature. Probably won't matter as it's well jammed in but there's a possibility the adapter will unscrew if the exhaust clamping ring is removed at a later date? Good job though.
Hi thanks for watching! The activator is for use on non-ferrous metal to help the cure, it also speeds the cure. I believe the loctite needs an ionic reaction ( copper ions?) as well as absence of air ( anaerobic ) to both bond and cure. Activator can also be used with steel to speed cure time or for large gaps where air may slow curing. As with most chemicals, skin contact not advised ( but we do, don't we! )
That's a standard indicator with a round nylon back stuck on with double sided tape that holds a couple of rare earth magnets. I use it to preposition the knee to height if I have to move it. I'll try and remember to show it in more detail in a video. Thanks for watching, Ade.
I was thinking of doing something similar with triumph heads. But instead of boring out the head and threading it, i was thinking of boring it out, and making an insert a light press fit into the head, and then tigging the insert in. finally threading the insert.
I would hope you have seen my earlier video on Triumph exhaust port thread repairs? I made 1.3/4" over-size inserts, taps this size can be quite reasonable prices on ebay, if you have a lathe for thread cutting to make the inserts. Look for Gordys Goodworks on TH-cam, he does a similar press fit/welded idea on a Triumph head. Honestly I have seen Norton heads with welded in press fit inserts break the weld when tightened up or have the weld crack in use. Personally I prefer a thread for all their known issues. What do other viewers think? Thanks for taking the time to comment, it is appreciated, Ade
A G Engineering Yes, belt and braces. Screw the insert in tight and weld the end up. Terrible design though, threads into aluminium and the steel stub screwed into it.
I've got an old bevel drive Ducati, they were notorious for trashing the exhaust threads. Both of the exhaust threads have been repaired with threaded inserts which are retained with a bead of weld.
Can't see the point of using Loctite 680 on the insert - according to the manufacturer's data the maximum temperature is 149*C for this grade , and the exhaust port will reach way beyond this in normal use.
Spot on observation, you'll like the next one where I use 638 then! As mentioned, this is experimental, the head may well end up in the scrap bin because there are more horrendous plans for it still. There are some more parts to this series to come. I have been looking at Minkon Fortafix ( Ouch very expensive, very high temp threadlock) and including a locking peg after assembly to avert potential unscrewing of the insert. I notice our American friends use JB Weld as a retainer, I'd be interested to know peoples thoughts on this.... The other thing to try is making the insert thread slightly over size and heating the head, then trying to screw the insert in before it grabs.....( I seriously doubt this would be possible) This has been mentioned in other posts on Norton forums etc. Thanks for watching and commenting, it's good to get some discussion going, sort of group problem solving! regards, Ade.
Mmmm, can't see JBWeld doing it myself. The shrink fit WOULD work but would have to be JUST right. Pretty difficult in practice. Have you thought of recessing the outside edge of the exhaust port and making the adapter thicker at the outside to fit inside the recess? You could make a better job of pegging it then. I fear the insert you just made would be too thin walled to peg.
It may be a possibility to make the insert flanged. I'm going to section an off-cut of insert to see how thick it is and if it may peg. I did do some snooping around on the net etc before this experiment started, take a look here:www.accessnorton.com/NortonCommando/documentary-exhaust-thread-repair.4289/
How much was the insert short by, not easy to see on the video. Could it have been because you need a little thread relief on the end of the insert? When I make inserts like that, I do the internal first so I can align the external thread with the internal for max wall thickness, ie no trough near a peak, but your insert seems thick enough to not worry about that . 648 is good to 180C according to Henkel, and that should be good enough. Although the pipe will get hot, the head should be under this high temp unless used in London traffic in the height of summer, if we ever get one. If you look at exhaust pipes that have gone blue, it is often a little away from the head, indicating that the head keeps the pipe cooler at the very end next to it. In the link you showed he was using thread locker, rather than a proper high temp retainer, perhaps the wrong choice?
The Bronze insert does not work as the expansion coefficient is lower than aluminium, my bronze insert backed out after a few years, the aluminium insert should work much better even if the loctite loses its grip.
Just make two little threaded holes on between the insert and the head port, let’s say 1/8” screw two stood’s make’ em flush and the insert will never comes out, period!!
Bad design norton triumph bonnie same also unbelievably Yamaha 600 or was it 650 can’t remember now I had a lot of problems with this bad idea never had an issue with Honda collet design though that’s one reason I went Japanese,,,,,,,,, reliability looking back still love the British machine s though
Some designs seem to be expensive to produce and not very good in practice, then once they are done, never get changed no matter what. The British Vs Japanese exhaust clamp methods is a good example of this. But then that's what makes them British! Thanks for watching, Ade
Got to take issue with Japanese design being any better, I have had to repair too many broken studs on them and it's even worse when the owner "helps" by drilling out the broken bit. I have developed special nuts to salvage the situation, if the is enough thread left, and the customer baulks at the cost of head removal.
Know where your coming from I have seen these issues you mention especially mr bodgit trying to drill it out and making a complete mess of it ,but I never had any problems. I owned 4 750 hondas over the years. Regards
Great to see another CVA No.79 Jig Borer/Mill still doing the job it was made to do over 70 years ago. Mine is in daily use and has been since I bought it 40 years ago.
Mine is perfect for the low ceiling of the workshop and is in great condition, very accurate and working well. I have been working on power down feed and crossfeed, which you may see in some video, that is still work in progress.
About 30 years ago I had a TRIUMPH Tiger 110 !!! A very powerful engine!
Thank you very much for sharing your work and videos.
Trying to keep classic bikes alive, one repair at a time! Pleased you are enjoying the channel, Ade
Excellent fit insert to head and rose to insert, many variables there a sure sign of someone who knows what they're doing! Excellent work many thanks for posting, cheers Jim.
Thanks for the vote of confidence James, much appreciated, Ade
Excellent work !!!! I send you a big hug from Argentina.
Thank you for the comment, best wishes, Ade
your hands are really like a goldsmith so delicate & precise- lots of respect & regards to you.
Thanks Rahul. I've not forgotten you, I'm still trying to find someone interested in helping with your project, it may take a little while yet. Be back to you when I have news. regards and best wishes, Ade.
Really good machine work there Ade well done mate.
Alan.
Thanks for watching Alan, all the best, Ade
i liked your previously on A G Engineering it was like episode of Columbo, that was a very useful video thanks for sharing
Thanks Andy, just trying something different!
i liked it keep it in, everyone should do that if they do videos in parts, as far as i know your the first
thats we call PERFECTION-- cheers from India
Rahul many thanks for your supportive comments
My local engineer always pins the insert. It's never failed yet. I find the bronze lock rings stay in the head far better than the standard rings, which tend to loosen on longer journeys. I don't recommend using the locking tabs with the lock rings as these don't stop the lock ring loosening, but allow them to be loosen just enough to damage the threads.
Great information 👍🏼
I owned a 1973 Interstate and could never keep the pipes tight. Did have the ports sleeved with bronze but the inserts eventually pulled out.
Recently I saw a different method of repair on a Roadster. It had spiggots welded into the ports with Triumph style externaly clamped pipes fitted.
The owner said he has had no trouble with the pipes since doing this repair. Can't comment on the long term success as I havn't seen the bike again.
Interesting way of doing a repair.I dare say there are several ways to improve the original pipe clamping method, problem is in 2019 most (not all) folks wanting a repair want to preserve the original 'look' of the bike, hence finding 'invisible' ways of doing the repair, not necessarily better. Thanks for the comment, Ade.
@@AGEngineeringAgreed, definately not for a show bike. Also possible distortion of the head from welding, extra heat transfer into head while running and possibly fatigue cracking of the spiggots at the pipe junction as there would only be about 6mm wall at that point. Still much less machining for a cheaper repair.
Yes, my Commando was a pain in the neck too. I made up oversized exhaust rings but the design puts way too much stress just there, especially on the Commando where the engine is allowed to dance around.
The reason commandos have issues is usually down to the amount of movement in the isolastics. This can be especially bad when aftermarket, ridgedly mounted silencers are fitted.
When in Machine Shop Operations schooling ('86-'87), this was a project the instructor Allowed me to do. We decided to machine a single point threaded set of sleeves, these being SLIGHTLY oversize . This required sticking them in the freezer and installing them immediately. I was a little slow with the one but managed to pound it the rest of the way home. Then, it was sent to Bobby the weld instructor(Sweetheart of a guy). He said he had a little difficulty welding them , and wondered if the alloy didn't contain a little Magnesium or something. Too many years ago.
Many thanks for taking the time to watch and comment, much appreciated, Ade
Do you actually expect that Loctite to withstand the extreme heat that area is exposed to??
Thanks for watching and commenting, please take a look through the comments on the various exhaust thread repair videos I have posted, there are many discussions on this controversial issue 😂
Why not cut internal thread 90% depth then tap. Great job by the way.
I have done that also, thanks for watching
Hi , not many use the 30 degree ½ included angle any more , compound set straight and just zero the compound slide and add clearance as required. Cheers
I use both ways, depending what I'm working on, thanks for watching and commenting
Hello, for the Norton exhaust nut tap you mentioned 1 15/16 - 14 Unified thread - is that a 55 degree thread angle?
The new exhaust rings are unified 60 degree, earlier Dommies were 55
@@AGEngineering
Myself and a family member both have Early Commandos (1971, 1972 & 1973) - would you consider these bikes "newer" and have a 60 degree thread in the exhaust port/nuts?
Your help is appreciated!
I will look to see if I can find my thread gauges as well.
Yes commando, atlas, later 650ss would be 60 degree. All the usual suppliers of new exhaust nuts/rings supply 60 degree, and usually they are not the greatest quality so are 'sloppy' enough to fit the worn original threads of earlier 55 degree head threads anyway.
It's quite difficult to determine the difference between 55 and 60 with thread gauges, I have had new and old nuts on my shadowgraph to measure thread angle.
Fascinating. Thanks.
Thanks for the support, Ade
Was there a 3rd instalment? ,l cant find it.
Unfortunately I never got to do one sorry, maybe one day 🤔
A-Plus from Canada!
Thank you for watching my old episodes Chris
The gap probably isn't a problem, and in fact will lock the ring in once the engine has been run a few miles. Modern shotguns use screwed in chokes with fine threads, and unless they are taken out and cleaned, the gasses enter any gaps and make them practically immovable.
Thank you for your thoughts, valid point. Many thanks for watching and commenting, Ade
I think you're going to lose must of the strength of the Loctite 680 at exhaust port temperature.
Probably won't matter as it's well jammed in but there's a possibility the adapter will unscrew if the exhaust clamping ring is removed at a later date?
Good job though.
Thanks for watching and commenting Peter, please see above reply to Gospelman on this issue. Kind regards, Ade
What does the Loctite activator do, why aren't you supposed to have it on your finger ?
Hi thanks for watching! The activator is for use on non-ferrous metal to help the cure, it also speeds the cure. I believe the loctite needs an ionic reaction ( copper ions?) as well as absence of air ( anaerobic ) to both bond and cure. Activator can also be used with steel to speed cure time or for large gaps where air may slow curing. As with most chemicals, skin contact not advised ( but we do, don't we! )
@@AGEngineering hello thanks for that
Out of curiosity, where did you get that magnetic-backed indicator on your mill's column?
That's a standard indicator with a round nylon back stuck on with double sided tape that holds a couple of rare earth magnets. I use it to preposition the knee to height if I have to move it. I'll try and remember to show it in more detail in a video. Thanks for watching, Ade.
Great work A G
Thank you Rob. How's sunny Lincolnshire?
A G Engineering it's not sunny😂
I was thinking of doing something similar with triumph heads. But instead of boring out the head and threading it, i was thinking of boring it out, and making an insert a light press fit into the head, and then tigging the insert in. finally threading the insert.
I would hope you have seen my earlier video on Triumph exhaust port thread repairs? I made 1.3/4" over-size inserts, taps this size can be quite reasonable prices on ebay, if you have a lathe for thread cutting to make the inserts. Look for Gordys Goodworks on TH-cam, he does a similar press fit/welded idea on a Triumph head. Honestly I have seen Norton heads with welded in press fit inserts break the weld when tightened up or have the weld crack in use. Personally I prefer a thread for all their known issues. What do other viewers think? Thanks for taking the time to comment, it is appreciated, Ade
Its just i don't fully trust loctite and those types of engineering adhesives, especially over a weld.
Maybe as Chris Stephens comments further down the post, threaded and the weld to prevent unscrewing?
A G Engineering
Yes, belt and braces. Screw the insert in tight and weld the end up. Terrible design though, threads into aluminium and the steel stub screwed into it.
I've got an old bevel drive Ducati, they were notorious for trashing the exhaust threads. Both of the exhaust threads have been repaired with threaded inserts which are retained with a bead of weld.
Can't see the point of using Loctite 680 on the insert - according to the manufacturer's data the maximum temperature is 149*C for this grade , and the exhaust port will reach way beyond this in normal use.
Spot on observation, you'll like the next one where I use 638 then! As mentioned, this is experimental, the head may well end up in the scrap bin because there are more horrendous plans for it still. There are some more parts to this series to come. I have been looking at Minkon Fortafix ( Ouch very expensive, very high temp threadlock) and including a locking peg after assembly to avert potential unscrewing of the insert. I notice our American friends use JB Weld as a retainer, I'd be interested to know peoples thoughts on this.... The other thing to try is making the insert thread slightly over size and heating the head, then trying to screw the insert in before it grabs.....( I seriously doubt this would be possible) This has been mentioned in other posts on Norton forums etc. Thanks for watching and commenting, it's good to get some discussion going, sort of group problem solving! regards, Ade.
www.ebay.co.uk/itm/Fortafix-High-Temperature-Thread-Lock-50ml-70gram/173135976058?hash=item284fb5567a:g:VUcAAOSwEfBZsSKt
Mmmm, can't see JBWeld doing it myself.
The shrink fit WOULD work but would have to be JUST right. Pretty difficult in practice.
Have you thought of recessing the outside edge of the exhaust port and making the adapter thicker at the outside to fit inside the recess? You could make a better job of pegging it then. I fear the insert you just made would be too thin walled to peg.
It may be a possibility to make the insert flanged. I'm going to section an off-cut of insert to see how thick it is and if it may peg. I did do some snooping around on the net etc before this experiment started, take a look here:www.accessnorton.com/NortonCommando/documentary-exhaust-thread-repair.4289/
How much was the insert short by, not easy to see on the video. Could it have been because you need a little thread relief on the end of the insert?
When I make inserts like that, I do the internal first so I can align the external thread with the internal for max wall thickness, ie no trough near a peak, but your insert seems thick enough to not worry about that
.
648 is good to 180C according to Henkel, and that should be good enough. Although the pipe will get hot, the head should be under this high temp unless used in London traffic in the height of summer, if we ever get one. If you look at exhaust pipes that have gone blue, it is often a little away from the head, indicating that the head keeps the pipe cooler at the very end next to it.
In the link you showed he was using thread locker, rather than a proper high temp retainer, perhaps the wrong choice?
The Bronze insert does not work as the expansion coefficient is lower than aluminium, my bronze insert backed out after a few years, the aluminium insert should work much better even if the loctite loses its grip.
Thanks for your thoughts
Just make two little threaded holes on between the insert and the head port, let’s say 1/8” screw two stood’s make’ em flush and the insert will never comes out, period!!
When (If) I get to doing a bronze insert version, that will be in the plan! Thanks for watching and commenting, Ade
Bad design norton triumph bonnie same also unbelievably Yamaha 600 or was it 650 can’t remember now I had a lot of problems with this bad idea never had an issue with Honda collet design though that’s one reason I went Japanese,,,,,,,,, reliability looking back still love the British machine s though
Some designs seem to be expensive to produce and not very good in practice, then once they are done, never get changed no matter what. The British Vs Japanese exhaust clamp methods is a good example of this. But then that's what makes them British! Thanks for watching, Ade
Got to take issue with Japanese design being any better, I have had to repair too many broken studs on them and it's even worse when the owner "helps" by drilling out the broken bit. I have developed special nuts to salvage the situation, if the is enough thread left, and the customer baulks at the cost of head removal.
Know where your coming from I have seen these issues you mention especially mr bodgit trying to drill it out and making a complete mess of it ,but I never had any problems. I owned 4 750 hondas over the years. Regards