Hi Paul, it occurs to me that the hole in the bush just might be deliberately excentric as a method of achieving tram on final assembly at the factory. In that case, the last job after tramming would be to dimple the bush for the locking screw. I'll have a look at the pin on my machine later
Chris that is technically possible as you say but my guess is they would put the bush in and then just ream it through in line with the head trammed. I think they just forgot the reaming on mine. Cheers
@@HaxbyShedHi Paul, I think that if I'd been building the machine, I would have done exactly as you say. I wonder if Harrisons had a production process where they had to allow for removing cumulative errors at the end of final assembly. I think I'll take the pin/bush assembly out of mine and see what it looks like!
That mill is getting better and better Paul. I bet its not been that good for decades. I think I'd make a new bush for it, tram it to within an inch of its life and then use the smallest standard taper reamer I could, imperial or metric to recut the taper to suit a standard taper pin.
Hi Matt, I think sometimes it would be quicker just to throw the original parts away and just start again but I always like to make the original part work first on the assumption that the "manufacturer knew best". But it also shows the subtle complexities which you don't see in the flashy videos which say "hey presto" it's done and everything is fantastic now. Cheers
Hi Paul. That's a right can of worms you've had to deal with. You could try making a new good tight fitting bush and tapered pin all in one piece. Your lathe topside is already set. So you could machine the taper running the spindle in reverse cutting the back side. You could use this like a plug guage. Make the tapered pin diameter section slightly larger so the bush doesn't bottom out. Also make the pin longer so you can tap it from the back to eject it. Just a thought. I think that the discrepancy you've got is all to do with the fit of that bush. Great job. I enjoyed watching your process. Just another thought. If you just crack the four head retaining nuts loose. Can you rotate the head in the direction required to true it up while the bush is in place. This may show the slight movement you require.....Tony
Hi Tony, I think your idea of the bush and pin combined is spot on. You know sometimes I don't know how Harrison came up with such poor designs - yes ok for the early models but you would think over the decades these machines were in production they could have improved it (in many areas). Still a good machine though, very capable for a small machine. Cheers
@@HaxbyShed Hi Paul. I think the bush is a time proven method. I'm assuming it's made that way to save removing the complete damaged head for re machining a tapered pin hole perfectly true again in the head casting. It just needs the bush hole re-bored larger in the lathe, then a tapered pin reamer started while the bush is chucked up. Then the bush is transferred back to the machine, the the head trammed in and locked in place. Then the tapered pin reamed is used to re-finish the bush and the machine main body at the same time. You don't need another milling machine with extra long tooling to reach the damaged hole in the head if it's done the other way around. Appreciate your reply comment. Tony
Hi Paul. A very interesting episode indeed. The taper pin in all probabilities will only get you within a few thousand of final tram. You did very well to get it oh so very close. 👏👏👍😀
This pin on your millhead reminds me of when I worked on a Cincinnati universal 14U Grinding m/c the headstock had the same taper pin, it was in good condition but I always had to jiggle it a bit one way or another, so yes I think your right to leave it at that, interesting video thanks for sharing, 🇬🇧 Coventry.
Hi Grahame, the thing is that, as a latecomer hobbyist, I sometimes lack the experience to know what matters so I usually try for 'perfection' when really it does not matter that much in the real world. Cheers
Yes, I agree that sometimes it just isn't worth aiming for perfection! Perhaps the accuracy of the pin location is limited by the radial location of the head on the other casting. Clearance between the two will limit angular accuracy. I think you did well to get that fit between the three components. Well done! Thanks for sharing.
Hello my friend you always see the hidden detail. Yes it does rely on the rotational fit between the vertical head front and back castings. Good catch. So I think it supports the case that the taper pin locator is accurate enough for most work, but may never be 100%. We have another comment saying a single pin will never be accurate but two pins opposed can be - probably for the reasons you flag. Good thinking. Cheers
Hi Max, yes it would be good to see how vertical Olga's head is with just the pin. 😁 You probably gather I like to check and analyse things to death but then I feel I know all I need to know (about anything). Cheers
I appreciate the work to make the pin, fix the bushing and then do the nudge-and-fudge to get the head trammed in without the pin since the pin is not as accurate as desired. Well done. My milling machine head does not have a registration pin, so I can only do nudge-and-fudge. This takes a LOT of time. I do not have screws to assist, jut the mallet moving too little or too much. I dread if I need to rotate the head for a future operation. Dave.
Hi Dave, there is no doubt the pin gets the head close very conveniently and then it's just a 'micro nudge' with the pin loose to get it spot on for those jobs that need it. Cheers
Hi Paul, Definitely a strange fish? Nice job on the taper. It doesn't matter how parallel the clarkson holder is, or any point of attachment when using it as a mounting point for tramming. Great job, thanks for sharing
Hi John, it took me quite a while to think of a way to check the vertical tram - I watched several 'over complicated' UA-cams before I came up with that way. And as you say, any error in the taper attachment does not affect the measurement. Cheers
Time for a few thoughts. It wasnt clear when you recut the taper in the bush whether you moved the cross slide to open the hole or whether you did it the easy way. By which i mean if have open it enough to move the pin in 7mm dont move the cross slide but move the saddle along that 7mm and you get it right without trying to move the ctoss slide a merest smidge. If you know this trick sorry for repeating but i know lots of folks don't. Now for your pin not setting the tram perfectly. One taper pin and a rotating stub will never reset each time because of the play in the rotating part. You can overcome this by preloading the head in the required direction when tightening the nuts. To get consistent zeroing you would need two taper pins opposite each other to lock the head accurately. I found this out when i got fed up with the rotating vice on my mill having to be retramed square after an angle cut. I drilled and taper reamed one hole but it didnt workout, so i did the same on the other side and hey presto perfect everytime. I have the same issue with my lathe toolpost but there i have the Dickson original pin hole and the centre pivot only, so i have to preload the toolpost when tightening, granted it only really matters to be dead nuts on square when using a parting tool but doesnt hurt tge redt of the time. Thinking of parting, if you have ptoblems of chatter, move the top slide fully to the right to effectively lock it like a solid mount before starting to part off. It does make a difference to the cut, a quick and cheap way of reducing the need of the popular trend of replacing top slide with a solid block in an effort to increase rigidity. Hope my "life lessons" aren't too boring, or im trying to teach my grannie how to suck eggs.😉
Hi Chris, well this guy did not know the trick either (i.e move the saddle not the topslide)! Such an obvious neat idea when you know. Thank you. I have made some investments in parting tooling which will make an appearance in due course. Cheers Paul
@@HaxbyShed the deleted message was the other me, the account I had planned to show the engineeringly bits of horrors that I get asked to fix. If it was deleted before it went in your cache, the gist of it was, I hope you meant move the saddle not the cross slide, you still need to move the top/compound slide to cut the taper, just further in but on the same radial setting. Perhaps one of us should do a video showing the trick as it seems it is not as widely known as it should be. Although I came up with idea, rather than being taught or read it, I have no doubt it is not an original idea as it is so obvious.
Hi, I saw your video about the taper pin. I have a selection of taper reamers and taper pins that you are welcome to have if you could use them. We are ten miles south of York.
Hi Ben, I kind of agree but it's fine within limits. The head swivels in a spigot which itself has a bit of play. As somebody pointed out, accuracy would require two taper pins opposed. Cheers
Hi Paul, really well presented video, well done!! Nice bit of wood turning as well!! Just curious, when perfectly trammed with the clock gauge how far out of alignment was the mark on the head? After all this your bound to find a taper reamer set at your next autojumble. Have a great weekend!!
When I get a moment I'll recheck the alignment mark on the head. It did look slightly off still, aligned on the taper pin. A viewer has offered me some taper pins and reamers and I will follow that up. Cheers Paul
Its a bit of a rough trick but you could skim just enough off the outside of the bush so that the pin will go in with the head perfectly tramed, then loctite the bush in place. As I said, a bit rough but should work. Cheers
I think it would work Peter. The bush has to come out to remove the T-head bolts that secure the vertical head front section so possibly a softer retaining loctite would be required rather than strong thread-locking loctite. Cheers
Maybe it could be useful to first tram perfectly and than give the tapered hole a touch of stone or something. It could well be that the original pin was bent due to a crach, and damnaged the hole. Just an idea.
Hi Michel, thinking about it now I think basically you are right. It would be best to set the head perfectly vertical first and then adjust the pin/bush to that. I often use "dead reckoning" when a simpler practical approach would be better actually. I assumed the manufacturer made it exactly vertical set with the taper pin when it left the factory and that may be a false assumption. Cheers
Thanks Paul, this is the one i have been waiting for! Is it possible that the hole in the centre of the bush is off centre on purpose, and the last job they would do in the factory would be to tram the mill, fit the taper pin, fit the bush, rotating it till it went in, and then mark the bush through the grub screw hole and drill the bush for the point of the grub screw? Theoretically you would then leave the bush in place and just remove the pin to move the head. Phil
Hi Phil. I was thinking down that line at first, but the theory wouldn't work. The bush hole would only align at the two points, near the top and near the bottom. As you rotate the bush, its hole centre would become out of line with a pre-machined hole in the main body. I think they've pre-bored the main machine body, pre bored the bush central, fitted the bush, locked it with the grub screw, tram the head in true, then hand taper ream, aligning both holes. Tony
@@eyuptony i take your point Tony but it takes a lot of effort to produce a slightly off centre bush in a lathe! However i first came to the conclusion because i thought the outer edge of the bush was knurled, but on re watching the video I don’t think it is! I will check my manual when i have a minute!
Hi Phil and Tony, I'm with Tony on this one. I think they pre-machine the tapered hole in the main body, trammed the head, put the bush in and then hand ream to "line bore" it. But in this case I think they forgot the reaming bit !! Another Friday job. Still it's only been like that for 50 years so we caught it in time😁 Cheers
@@HaxbyShed I have thought some more and I think you are both right, even the slightest offset of the centre hole would cause it to bind at two points!
@@HaxbyShed Hi Paul. It would have been a good fit when new but the gorilla's bashing that tapered pin in to try and realign the head will have ruined all the three components. The machine body hole, the bush and the pin. They must have given that pin a fair old wack to bend it. Cheers Tony
I think you are doing more than it's worth. On my mill the head is out of tram on purpose, this way it's cutting on one side only with a 200mm cutter. The reason is when I'm resurfacing a cylinder head it leaves a mirror finish. If the head is in perdect tram then when the front of the cutter leaves the cut it sinks ever so slightly and marring up the last bit of the surface. In the real world besides the precision instruments the level of precision is much less then what you are looking for. Just measure how much your table snags in the far end of it travel. The world is made out of rubber as they say. Have a nice day.
Hi Mr Logan880121. Thank you for that advice. My son wants his cylinder head skimming and sometime I will make a suitable fly cutter. Knowing to give it a slight lift on the front is helpful thanks. Cheers
Hi, good spot thanks. I agree the 75mm should have been written against the longest side on the drawing, yes. But I think my calculation is right because I used Sin = O/H. Misleading I agree. Off camera slips like that don't matter but when you claim to be explaining how it should be done it's a bit embarrassing 😒 Cheers
Hi John, yes I probably could. I think by that stage I had just had enough messing for that day. It would be easy enough to do as you suggest, when I'm in the mood for a small job. Cheers
Your bush is crap. You can see the inner part flopping around in the outer shell. Replace the shell with ANYTHING and you'll be fine. Or better anyway.
Hi skyfreakwi, sure yes you are right. I always try to make the original parts work if I can but I agree that bush is a bit of a lost cause and a new one would be better. Cheers
Hi Paul,
it occurs to me that the hole in the bush just might be deliberately excentric as a method of achieving tram on final assembly at the factory. In that case, the last job after tramming would be to dimple the bush for the locking screw. I'll have a look at the pin on my machine later
I had that same thought. Being eccentric, perhaps the bush could then be realigned to account for future wear? 🤔
Chris that is technically possible as you say but my guess is they would put the bush in and then just ream it through in line with the head trammed. I think they just forgot the reaming on mine. Cheers
@@HaxbyShedHi Paul, I think that if I'd been building the machine, I would have done exactly as you say. I wonder if Harrisons had a production process where they had to allow for removing cumulative errors at the end of final assembly. I think I'll take the pin/bush assembly out of mine and see what it looks like!
That mill is getting better and better Paul. I bet its not been that good for decades.
I think I'd make a new bush for it, tram it to within an inch of its life and then use the smallest standard taper reamer I could, imperial or metric to recut the taper to suit a standard taper pin.
Bill yes that would work, I'm not sure why they used a bespoke angle pin. Cheers
Cheers Paul. I admire your tenacity!
Hi Matt, I think sometimes it would be quicker just to throw the original parts away and just start again but I always like to make the original part work first on the assumption that the "manufacturer knew best". But it also shows the subtle complexities which you don't see in the flashy videos which say "hey presto" it's done and everything is fantastic now. Cheers
Excellent Paul, just the type of film I like to watch. And very useful to me.Thanks.
You are welcome Carl, glad it was useful. At least now you know what to expect on yours - we can compare. Cheers
Hi Paul. That's a right can of worms you've had to deal with. You could try making a new good tight fitting bush and tapered pin all in one piece. Your lathe topside is already set. So you could machine the taper running the spindle in reverse cutting the back side. You could use this like a plug guage. Make the tapered pin diameter section slightly larger so the bush doesn't bottom out. Also make the pin longer so you can tap it from the back to eject it. Just a thought. I think that the discrepancy you've got is all to do with the fit of that bush. Great job. I enjoyed watching your process. Just another thought. If you just crack the four head retaining nuts loose. Can you rotate the head in the direction required to true it up while the bush is in place. This may show the slight movement you require.....Tony
Hi Tony, I think your idea of the bush and pin combined is spot on. You know sometimes I don't know how Harrison came up with such poor designs - yes ok for the early models but you would think over the decades these machines were in production they could have improved it (in many areas). Still a good machine though, very capable for a small machine. Cheers
@@HaxbyShed Hi Paul. I think the bush is a time proven method. I'm assuming it's made that way to save removing the complete damaged head for re machining a tapered pin hole perfectly true again in the head casting. It just needs the bush hole re-bored larger in the lathe, then a tapered pin reamer started while the bush is chucked up. Then the bush is transferred back to the machine, the the head trammed in and locked in place. Then the tapered pin reamed is used to re-finish the bush and the machine main body at the same time. You don't need another milling machine with extra long tooling to reach the damaged hole in the head if it's done the other way around. Appreciate your reply comment. Tony
Hi Paul. A very interesting episode indeed. The taper pin in all probabilities will only get you within a few thousand of final tram. You did very well to get it oh so very close. 👏👏👍😀
Hi Andrew, we'll see how I get on when theory meets practical world. I'm pretty happy with it now. Cheers
This pin on your millhead reminds me of when I worked on a Cincinnati universal 14U Grinding m/c the headstock had the same taper pin, it was in good condition but I always had to jiggle it a bit one way or another, so yes I think your right to leave it at that, interesting video thanks for sharing, 🇬🇧 Coventry.
Hi Grahame, the thing is that, as a latecomer hobbyist, I sometimes lack the experience to know what matters so I usually try for 'perfection' when really it does not matter that much in the real world. Cheers
Yes, I agree that sometimes it just isn't worth aiming for perfection! Perhaps the accuracy of the pin location is limited by the radial location of the head on the other casting. Clearance between the two will limit angular accuracy.
I think you did well to get that fit between the three components. Well done! Thanks for sharing.
Hello my friend you always see the hidden detail. Yes it does rely on the rotational fit between the vertical head front and back castings. Good catch. So I think it supports the case that the taper pin locator is accurate enough for most work, but may never be 100%. We have another comment saying a single pin will never be accurate but two pins opposed can be - probably for the reasons you flag. Good thinking. Cheers
Hi Paul, wonderful video, cheers from the US, Florida, Paul
Hi Paul, I bet Florida is a bit warmer than here. Cheers
@@HaxbyShed heading into winter here, gets into the 80's f in the days and down in the 70's at night....stay warm my friend, Paul
Great end result . My big mill has a similar pin arrangement , will be interesting to check how true they are ...or not . 👍
Hi Max, yes it would be good to see how vertical Olga's head is with just the pin. 😁 You probably gather I like to check and analyse things to death but then I feel I know all I need to know (about anything). Cheers
I appreciate the work to make the pin, fix the bushing and then do the nudge-and-fudge to get the head trammed in without the pin since the pin is not as accurate as desired. Well done.
My milling machine head does not have a registration pin, so I can only do nudge-and-fudge. This takes a LOT of time. I do not have screws to assist, jut the mallet moving too little or too much. I dread if I need to rotate the head for a future operation.
Dave.
Hi Dave, there is no doubt the pin gets the head close very conveniently and then it's just a 'micro nudge' with the pin loose to get it spot on for those jobs that need it. Cheers
Hi Paul,
Definitely a strange fish? Nice job on the taper.
It doesn't matter how parallel the clarkson holder is, or any point of attachment when using it as a mounting point for tramming.
Great job, thanks for sharing
Hi John, it took me quite a while to think of a way to check the vertical tram - I watched several 'over complicated' UA-cams before I came up with that way. And as you say, any error in the taper attachment does not affect the measurement. Cheers
Gday Paul, it’s a lot better then what you started with, I reckon that plenty close enough mate, cheers
Hi Matty, it seems none of these jobs are simple and I can easily be tripped up with the detail but I enjoy solving the puzzle. All the best, Paul
Time for a few thoughts.
It wasnt clear when you recut the taper in the bush whether you moved the cross slide to open the hole or whether you did it the easy way. By which i mean if have open it enough to move the pin in 7mm dont move the cross slide but move the saddle along that 7mm and you get it right without trying to move the ctoss slide a merest smidge. If you know this trick sorry for repeating but i know lots of folks don't.
Now for your pin not setting the tram perfectly. One taper pin and a rotating stub will never reset each time because of the play in the rotating part. You can overcome this by preloading the head in the required direction when tightening the nuts. To get consistent zeroing you would need two taper pins opposite each other to lock the head accurately. I found this out when i got fed up with the rotating vice on my mill having to be retramed square after an angle cut. I drilled and taper reamed one hole but it didnt workout, so i did the same on the other side and hey presto perfect everytime. I have the same issue with my lathe toolpost but there i have the Dickson original pin hole and the centre pivot only, so i have to preload the toolpost when tightening, granted it only really matters to be dead nuts on square when using a parting tool but doesnt hurt tge redt of the time. Thinking of parting, if you have ptoblems of chatter, move the top slide fully to the right to effectively lock it like a solid mount before starting to part off. It does make a difference to the cut, a quick and cheap way of reducing the need of the popular trend of replacing top slide with a solid block in an effort to increase rigidity.
Hope my "life lessons" aren't too boring, or im trying to teach my grannie how to suck eggs.😉
Hi Chris, well this guy did not know the trick either (i.e move the saddle not the topslide)! Such an obvious neat idea when you know. Thank you. I have made some investments in parting tooling which will make an appearance in due course. Cheers Paul
@@HaxbyShed the deleted message was the other me, the account I had planned to show the engineeringly bits of horrors that I get asked to fix.
If it was deleted before it went in your cache, the gist of it was, I hope you meant move the saddle not the cross slide, you still need to move the top/compound slide to cut the taper, just further in but on the same radial setting.
Perhaps one of us should do a video showing the trick as it seems it is not as widely known as it should be. Although I came up with idea, rather than being taught or read it, I have no doubt it is not an original idea as it is so obvious.
Another good effort!
Thanks LE. It seems everything I work on has hidden complexities. Very few jobs are actually as straight forward as they seem. Cheers
Hi, I saw your video about the taper pin. I have a selection of taper reamers and taper pins that you are welcome to have if you could use them. We are ten miles south of York.
Hi Stuart that would be great, could you send me a message to the email address in my 'about' section on my channel page? Thanks Paul
whats the use of a location-pin if its not dead on accurat ?
cheers ben.
Hi Ben, I kind of agree but it's fine within limits. The head swivels in a spigot which itself has a bit of play. As somebody pointed out, accuracy would require two taper pins opposed. Cheers
Hi Paul, really well presented video, well done!! Nice bit of wood turning as well!!
Just curious, when perfectly trammed with the clock gauge how far out of alignment was the mark on the head?
After all this your bound to find a taper reamer set at your next autojumble.
Have a great weekend!!
When I get a moment I'll recheck the alignment mark on the head. It did look slightly off still, aligned on the taper pin. A viewer has offered me some taper pins and reamers and I will follow that up. Cheers Paul
Its a bit of a rough trick but you could skim just enough off the outside of the bush so that the pin will go in with the head perfectly tramed, then loctite the bush in place. As I said, a bit rough but should work.
Cheers
I think it would work Peter. The bush has to come out to remove the T-head bolts that secure the vertical head front section so possibly a softer retaining loctite would be required rather than strong thread-locking loctite. Cheers
Maybe it could be useful to first tram perfectly and than give the tapered hole a touch of stone or something. It could well be that the original pin was bent due to a crach, and damnaged the hole. Just an idea.
Hi Michel, thinking about it now I think basically you are right. It would be best to set the head perfectly vertical first and then adjust the pin/bush to that. I often use "dead reckoning" when a simpler practical approach would be better actually. I assumed the manufacturer made it exactly vertical set with the taper pin when it left the factory and that may be a false assumption. Cheers
Thanks Paul, this is the one i have been waiting for! Is it possible that the hole in the centre of the bush is off centre on purpose, and the last job they would do in the factory would be to tram the mill, fit the taper pin, fit the bush, rotating it till it went in, and then mark the bush through the grub screw hole and drill the bush for the point of the grub screw? Theoretically you would then leave the bush in place and just remove the pin to move the head.
Phil
Hi Phil. I was thinking down that line at first, but the theory wouldn't work. The bush hole would only align at the two points, near the top and near the bottom. As you rotate the bush, its hole centre would become out of line with a pre-machined hole in the main body. I think they've pre-bored the main machine body, pre bored the bush central, fitted the bush, locked it with the grub screw, tram the head in true, then hand taper ream, aligning both holes. Tony
@@eyuptony i take your point Tony but it takes a lot of effort to produce a slightly off centre bush in a lathe! However i first came to the conclusion because i thought the outer edge of the bush was knurled, but on re watching the video I don’t think it is! I will check my manual when i have a minute!
Hi Phil and Tony, I'm with Tony on this one. I think they pre-machine the tapered hole in the main body, trammed the head, put the bush in and then hand ream to "line bore" it. But in this case I think they forgot the reaming bit !! Another Friday job. Still it's only been like that for 50 years so we caught it in time😁 Cheers
@@HaxbyShed I have thought some more and I think you are both right, even the slightest offset of the centre hole would cause it to bind at two points!
@@HaxbyShed Hi Paul. It would have been a good fit when new but the gorilla's bashing that tapered pin in to try and realign the head will have ruined all the three components. The machine body hole, the bush and the pin. They must have given that pin a fair old wack to bend it. Cheers Tony
I think you are doing more than it's worth. On my mill the head is out of tram on purpose, this way it's cutting on one side only with a 200mm cutter. The reason is when I'm resurfacing a cylinder head it leaves a mirror finish. If the head is in perdect tram then when the front of the cutter leaves the cut it sinks ever so slightly and marring up the last bit of the surface. In the real world besides the precision instruments the level of precision is much less then what you are looking for. Just measure how much your table snags in the far end of it travel. The world is made out of rubber as they say. Have a nice day.
Hi Mr Logan880121. Thank you for that advice. My son wants his cylinder head skimming and sometime I will make a suitable fly cutter. Knowing to give it a slight lift on the front is helpful thanks. Cheers
@@HaxbyShed you have to lean in to the cut. So the front is cutting not the back. It will make a konkav surface, but it's so little it doesn't matter.
The hypotenuse should be 75 mm when calculating the length of the short leg. It won't make much of a difference in this case though.
Hi, good spot thanks. I agree the 75mm should have been written against the longest side on the drawing, yes. But I think my calculation is right because I used Sin = O/H. Misleading I agree. Off camera slips like that don't matter but when you claim to be explaining how it should be done it's a bit embarrassing 😒 Cheers
Interesting!
Thanks Danny. 👍
The bush is off Center why can you not just rotate it and re pin it to your zero ?
Hi John, yes I probably could. I think by that stage I had just had enough messing for that day. It would be easy enough to do as you suggest, when I'm in the mood for a small job. Cheers
Your bush is crap. You can see the inner part flopping around in the outer shell. Replace the shell with ANYTHING and you'll be fine. Or better anyway.
Hi skyfreakwi, sure yes you are right. I always try to make the original parts work if I can but I agree that bush is a bit of a lost cause and a new one would be better. Cheers