Just a short note. No real work done this week due work and deciding to order in some tooling and supplies before I continue the project. See you next week, provided my parts arrive on time.
Harold
Saturday 22 February 2014
Saturday 15 February 2014
Well my post this week will not be as long as last week's nor will it have as many items done. Never got in the shop until Saturday. At least we have a nice day here sunshine and just above freezing. Hopefully later this week it is supposed to go higher with 4-5C temp and possible rain. This will go along way to getting rid of some of that lousy white stuff around here. With the snow on my roof the solar panels are not making me any money this past month.
Meanwhile in the shop this morning we turned the blank around so we could machine the other end of the "shake adjusting nut". Last week I machined the pocket that would hold the bearing in it. This week I would machine the end that goes onto the large sprocket that mounts on the headstock spindle. This has a threaded connection between the two such that when you unscrew it, it pushes against the thrust bearing which secures the entire headstock assembly inside the headstock casting. For those who may not know what I'm talking about (Sis) here is a picture.
The above drawing from the 1919 brochure should help. This is a cross section of the headstock, the "shake adjusting nut" is the item with red ink on it. The "large sprocket assembly" mentioned above has the blue line in it and the "thrust bearing" has the green line in it. Since the sprocket assembly is secured to the headstock shaft which runs through the centre of the headstock, when you unscrew the shake adjusting nut it will push up against the thrust washer which in turn pushes up against the headstock casting. This then removes any horizontal slop out of the headstock assembly. Actually a pretty simple system when you think about it. You do not need a lot of torque on this assembly just enough to snug the bearing up securely.
So we flipped the blank around set it up in the 4 jaw chuck and carefully dialled it in such that we had less than 1thou runout on the previously machined surface. Unfortunately the picture showing this was way out of focus. Once it was dialled in we carefully machined out the inner dimension to allow the headstock shaft to come through the nut. We then machined out the pocket where the thread would go. Once that was done we machined two slightly deeper pockets one at the front of the nut and one 1inch into the pocket which would be depressions on either end of the thread to allow easier threading. Once this was done we machined the outside to the correct dimension to allow the sprocket assembly to slide over top. We checked this out with the sprocket assembly before starting the threading operation.
Here are two pictures first one showing the old nut, the second one showing the new nut ready for threading along with the old one sitting beside it on the lathe.
Carefully using thread gauges I determined that the thread was 24tpi. Set the lathe up to cut this thread and then carefully went at it. Threaded this by 5thous increments. Once we got to 25thous depth checked the piece with the sprocket assembly. It would start but that was all so went in again at 2.5thous increments and after two more passes got the assembly to thread on. I was quite happy as it seemed to thread on really nicely. However once I went to unthread the assembly it went 5-6 turns and then started binding up. I was frustrated in that after a few attempts to unthread it it would not come off. We persisted and slowly using a pin wrench managed to unthread the assembly. So went back in and carefully cleaned out the threads again with the threading bar and took three spring cuts to entirely clean out the thread. This time it spun on and off quite easily but with no slop on the thread. So I think a job well done. Here are two pictures. The first one is when I initially spun the sprocket on and the second one is once the threads were cleaned out some more. This time the entire assembly is out of the lathe.
The only thing left to do is decide whether to place knurls back on the nut like my two originals had, which gave you the gripping surface to tighten the nut. Or would insert either grooves or pin holes to use the adjustable pin or slot wrenches. A couple of the other owners with lathes newer than mine have the slots in the nut however I noticed on one of these machines these slots were quite badly damaged. I think boring 3holes in the nut at 120degreees almost through the flange area might be cleaner and less susceptible to damage down the road. I will have to think about this. I'll decide by the end of the week and then either bore it, slot it or knurl it. The only issue against the hole is I would need to buy the pin wrench required for the diameter of the nut since I don't have one at this time.
So that was all we did this week however I'm glad it's done. I'll most likely have to make at least one more for the #39 lathe somewhere down the road as it's nut is also damaged. However I'll probably wait awhile as I would like to see how this one lasts and works. I'm a little concerned that I might have used the wrong material. I used 12L14 round stock for this based on ease of machinability and the quality of the metal. Its tensile and shear strength looked good and the usage of this material was stated as being good for this type of application. Well the material machines beautifully however I noticed that just securing it in the 4 jaw chuck left little marks on the metal where the chuck jaws dug in. There was no real concern about this marking because it was easily cleaned off however it did leave me with a little concern about the strength of the material. However as mentioned before there is no real torque or pressure on this nut so it should still work as required. I might though look at getting a piece of Durabar for the next nut.
Now we need to look at working on assembling the headstock. The only issue I would like to resolve first is the damaged teeth on the back gear and one on the large sprocket. Decisions, decisions. I Most likely just drill, tap and pin into the large sprocket and then fill it with braze material before grinding it back down to the right profile and there's a good chance I'll do the same with the other broken teeth. One thing I'm waiting on is some special welding rod that can be used with my Tig welder that should take the place of brazing. Once I recieve this will trial some repairs on damaged gears and see how this material works.
Well until next week enjoy the weather and the Olympics especially when Canada gets the gold medal in Hockey :=):=)
Harold
Meanwhile in the shop this morning we turned the blank around so we could machine the other end of the "shake adjusting nut". Last week I machined the pocket that would hold the bearing in it. This week I would machine the end that goes onto the large sprocket that mounts on the headstock spindle. This has a threaded connection between the two such that when you unscrew it, it pushes against the thrust bearing which secures the entire headstock assembly inside the headstock casting. For those who may not know what I'm talking about (Sis) here is a picture.
The above drawing from the 1919 brochure should help. This is a cross section of the headstock, the "shake adjusting nut" is the item with red ink on it. The "large sprocket assembly" mentioned above has the blue line in it and the "thrust bearing" has the green line in it. Since the sprocket assembly is secured to the headstock shaft which runs through the centre of the headstock, when you unscrew the shake adjusting nut it will push up against the thrust washer which in turn pushes up against the headstock casting. This then removes any horizontal slop out of the headstock assembly. Actually a pretty simple system when you think about it. You do not need a lot of torque on this assembly just enough to snug the bearing up securely.
So we flipped the blank around set it up in the 4 jaw chuck and carefully dialled it in such that we had less than 1thou runout on the previously machined surface. Unfortunately the picture showing this was way out of focus. Once it was dialled in we carefully machined out the inner dimension to allow the headstock shaft to come through the nut. We then machined out the pocket where the thread would go. Once that was done we machined two slightly deeper pockets one at the front of the nut and one 1inch into the pocket which would be depressions on either end of the thread to allow easier threading. Once this was done we machined the outside to the correct dimension to allow the sprocket assembly to slide over top. We checked this out with the sprocket assembly before starting the threading operation.
Here are two pictures first one showing the old nut, the second one showing the new nut ready for threading along with the old one sitting beside it on the lathe.
Carefully using thread gauges I determined that the thread was 24tpi. Set the lathe up to cut this thread and then carefully went at it. Threaded this by 5thous increments. Once we got to 25thous depth checked the piece with the sprocket assembly. It would start but that was all so went in again at 2.5thous increments and after two more passes got the assembly to thread on. I was quite happy as it seemed to thread on really nicely. However once I went to unthread the assembly it went 5-6 turns and then started binding up. I was frustrated in that after a few attempts to unthread it it would not come off. We persisted and slowly using a pin wrench managed to unthread the assembly. So went back in and carefully cleaned out the threads again with the threading bar and took three spring cuts to entirely clean out the thread. This time it spun on and off quite easily but with no slop on the thread. So I think a job well done. Here are two pictures. The first one is when I initially spun the sprocket on and the second one is once the threads were cleaned out some more. This time the entire assembly is out of the lathe.
The only thing left to do is decide whether to place knurls back on the nut like my two originals had, which gave you the gripping surface to tighten the nut. Or would insert either grooves or pin holes to use the adjustable pin or slot wrenches. A couple of the other owners with lathes newer than mine have the slots in the nut however I noticed on one of these machines these slots were quite badly damaged. I think boring 3holes in the nut at 120degreees almost through the flange area might be cleaner and less susceptible to damage down the road. I will have to think about this. I'll decide by the end of the week and then either bore it, slot it or knurl it. The only issue against the hole is I would need to buy the pin wrench required for the diameter of the nut since I don't have one at this time.
So that was all we did this week however I'm glad it's done. I'll most likely have to make at least one more for the #39 lathe somewhere down the road as it's nut is also damaged. However I'll probably wait awhile as I would like to see how this one lasts and works. I'm a little concerned that I might have used the wrong material. I used 12L14 round stock for this based on ease of machinability and the quality of the metal. Its tensile and shear strength looked good and the usage of this material was stated as being good for this type of application. Well the material machines beautifully however I noticed that just securing it in the 4 jaw chuck left little marks on the metal where the chuck jaws dug in. There was no real concern about this marking because it was easily cleaned off however it did leave me with a little concern about the strength of the material. However as mentioned before there is no real torque or pressure on this nut so it should still work as required. I might though look at getting a piece of Durabar for the next nut.
Now we need to look at working on assembling the headstock. The only issue I would like to resolve first is the damaged teeth on the back gear and one on the large sprocket. Decisions, decisions. I Most likely just drill, tap and pin into the large sprocket and then fill it with braze material before grinding it back down to the right profile and there's a good chance I'll do the same with the other broken teeth. One thing I'm waiting on is some special welding rod that can be used with my Tig welder that should take the place of brazing. Once I recieve this will trial some repairs on damaged gears and see how this material works.
Well until next week enjoy the weather and the Olympics especially when Canada gets the gold medal in Hockey :=):=)
Harold
Saturday 8 February 2014
I tell you I've had enough of this white stuff around me. Spent half the week moving snow around. Now we aren't as bad as some areas, however when you're not use to it, it just sucks. If we get any more I might run out of room for the snow I've cleared. Oh well can't beat Mother Nature she just keeps doing her thing. I am glad though that I bought a snow blower years ago, it definitely has gotten used this year.
Ok last week I left you with the Overhead drive mounted and the transmission installed. When I wasn't shovelling snow I managed to get some time to work in the shop. First thing I did was go to install the eccentric shaft on the front of the casting which is used to raise and lower the three step pulley assembly so that you can engage or disengage the drive belt. Also allows you to take pressure off the belt while you are not using the lathe. This shaft has a divot at one end where a pointed screw goes in to secure the shaft in the casting. Then on the piece of the shaft that extends outside of the casting is a machined flat spot for the set screw from the handle that goes on there. I installed the shaft so the screw engaged the divot then installed the handle so that the setscrew came out on the flat spot. Low and behold the handle does not sit where I expected it to and the movement makes no sense since there are two pins used as stops for the handle and the handle was no where near them. As well the handle has a ball bearingunder pressure from a spring that should go into two detents on the flange of the shaft when it is in the engaged and disengaged positions. After scratching my head for a while and sending off an email to the other owners who have this drive assembly I took a closer look at the shaft. After doing a close inspection at one end I noticed that the flange portion was actually a separate piece. Once we got this apart and cleaned up then the installation went as it should go. Here are some pictures showing what I mean.
First picture shows how the handle looked first time it was installed and you can see the two dots from the broken studs. Second picture shows the shaft with the divot in it as it was removed from the casting. Third picture shows the flange portion removed. Once this occurred the flange could be inserted in the casting and secured by the screw into the divot and the shaft was free to rotate in the flange piece allowing the handle to be mounted correctly so that it moved from stud to stud and the ball bearing went into the detents as it should as well.
I also quickly cleaned, primed and painted the two doors that go on the casting. I want to thank Tyler in California for allowing me to purchase the front door that went with this overhead drive. Later this summer I'll make a pattern for that door so we can get a new one cast to send back to him for his lathe. Here are four pictures showing the doors installed and what they cover.
As well I took some time to clean and paint the guard that goes over the gears just to the left of the headstock. When I was moving stuff and cleaning up in the shop I found this on a shelf, evidently forgot to do this when I was working on that area. Here is a picture showing the parts polished and the bracket awaiting cleaning and painting.
Now that this was done it is time to start working on getting my headstock back together. One of the first things we need to do is work on machining a new "shake adjusting nut". Previously I had purchased a 9" long pieced of 12L14 stock 3.75" dia to use to make the part. Cut off a 2.5" chunk and went to mount it in the chuck. Planned on using the three jaw since I had just confirmed it's accuracy earlier this week. I actually spent an hour checking out the lathe with a test bar prior to starting work on this piece. Was quite surprised at how good the numbers were. However the three jaw does not have reversible jaws and it was not big enough to mount the blank. So we removed this chuck and installed the four jaw chuck instead. Now, I find out that I don't have a chuck key for this chuck. So over to the toolbox to take out a couple of 1/4" drive ratchets and used them as chuck keys. Mounted the blank, dialled it in and started the machining process. I decided that the I would first work on the side that goes over the bearing that this nut presses up against. The bearing then is pushed against one end of the headstock to put tension on the whole headstock assembly. On my original nut there were three small knurled lines that would be used to grip the nut to tighten or loosen it. You do not put a lot of torque on this nut just enough to seat the bearing against the headstock wall. So essentially hand tight plus a little is all that is needed. Then there is a set screw that secures this nut to prevent it from loosening. I could machine this in the nut or I could elect to machine it similar to other machines which have three pin holes for a pin wrench or slots for a slot wrench. I've machined the piece down so I can still do either method. Once the outside was done I bored out the centre to the inner diameter needed to slip over the headstock shaft. Then we machined out the pocket where the bearing goes. This took a little bit of time as I don't normally take more than 20thous at one pass and I needed to remove almost 2.5" of material however the metal machined easily so the lathe did not have to work to hard. Now that this side is done I can flip it over and mount it back up in the 4 jaw dial it in and machine out the other side. This one will be a little more complicated as I need to machine to better tolerances to allow me to thread it so that it fits onto the other part of the headstock. So here are some pictures of the process. The first picture shows the receiver on the left that the "nut" screws into, the nut and the blank I bought. Second picture has my sawn off blank ready for the lathe. Just so you see the third pictures shows where the nut threads into. Even after cleaning and some honing of the stock it is still hard to get the nut into the receiver and to start the thread. I'll have to be real careful when I machine this areas as the tolerances must be very close. Fourth picture is on the lathe part way through the boring process, and the fifth picture shows the one half of the blank all done with the original nut laying beside it.
Ok last week I left you with the Overhead drive mounted and the transmission installed. When I wasn't shovelling snow I managed to get some time to work in the shop. First thing I did was go to install the eccentric shaft on the front of the casting which is used to raise and lower the three step pulley assembly so that you can engage or disengage the drive belt. Also allows you to take pressure off the belt while you are not using the lathe. This shaft has a divot at one end where a pointed screw goes in to secure the shaft in the casting. Then on the piece of the shaft that extends outside of the casting is a machined flat spot for the set screw from the handle that goes on there. I installed the shaft so the screw engaged the divot then installed the handle so that the setscrew came out on the flat spot. Low and behold the handle does not sit where I expected it to and the movement makes no sense since there are two pins used as stops for the handle and the handle was no where near them. As well the handle has a ball bearingunder pressure from a spring that should go into two detents on the flange of the shaft when it is in the engaged and disengaged positions. After scratching my head for a while and sending off an email to the other owners who have this drive assembly I took a closer look at the shaft. After doing a close inspection at one end I noticed that the flange portion was actually a separate piece. Once we got this apart and cleaned up then the installation went as it should go. Here are some pictures showing what I mean.
First picture shows how the handle looked first time it was installed and you can see the two dots from the broken studs. Second picture shows the shaft with the divot in it as it was removed from the casting. Third picture shows the flange portion removed. Once this occurred the flange could be inserted in the casting and secured by the screw into the divot and the shaft was free to rotate in the flange piece allowing the handle to be mounted correctly so that it moved from stud to stud and the ball bearing went into the detents as it should as well.
Once that was done we could install the three step pulley assembly and then mount the chains on the sprockets. I had to remove the assembly once to adjust the location of the sprockets so that the chain could run true. The sprockets have set screws as well as woodruff keys to prevent them from spinning however there is nothing to tell you where to lock them down until you see how the chain runs. As it was they are locked down right against the new Oilite washers I installed against the casting arm. Here are three pictures the first shows the three step pulley assembly installed and the other two show the handles as they should be. Up for when lathe is running and putting tension on the belt and down when the lathe is not running so as to take tension off the belt. I should also mention you can see a threaded rod with knurled handle in the centre of the three step pulley assembly. This allows you to tighten or loosen the belt tension as the belt wears down over time.
I also quickly cleaned, primed and painted the two doors that go on the casting. I want to thank Tyler in California for allowing me to purchase the front door that went with this overhead drive. Later this summer I'll make a pattern for that door so we can get a new one cast to send back to him for his lathe. Here are four pictures showing the doors installed and what they cover.
As well I took some time to clean and paint the guard that goes over the gears just to the left of the headstock. When I was moving stuff and cleaning up in the shop I found this on a shelf, evidently forgot to do this when I was working on that area. Here is a picture showing the parts polished and the bracket awaiting cleaning and painting.
Now that this was done it is time to start working on getting my headstock back together. One of the first things we need to do is work on machining a new "shake adjusting nut". Previously I had purchased a 9" long pieced of 12L14 stock 3.75" dia to use to make the part. Cut off a 2.5" chunk and went to mount it in the chuck. Planned on using the three jaw since I had just confirmed it's accuracy earlier this week. I actually spent an hour checking out the lathe with a test bar prior to starting work on this piece. Was quite surprised at how good the numbers were. However the three jaw does not have reversible jaws and it was not big enough to mount the blank. So we removed this chuck and installed the four jaw chuck instead. Now, I find out that I don't have a chuck key for this chuck. So over to the toolbox to take out a couple of 1/4" drive ratchets and used them as chuck keys. Mounted the blank, dialled it in and started the machining process. I decided that the I would first work on the side that goes over the bearing that this nut presses up against. The bearing then is pushed against one end of the headstock to put tension on the whole headstock assembly. On my original nut there were three small knurled lines that would be used to grip the nut to tighten or loosen it. You do not put a lot of torque on this nut just enough to seat the bearing against the headstock wall. So essentially hand tight plus a little is all that is needed. Then there is a set screw that secures this nut to prevent it from loosening. I could machine this in the nut or I could elect to machine it similar to other machines which have three pin holes for a pin wrench or slots for a slot wrench. I've machined the piece down so I can still do either method. Once the outside was done I bored out the centre to the inner diameter needed to slip over the headstock shaft. Then we machined out the pocket where the bearing goes. This took a little bit of time as I don't normally take more than 20thous at one pass and I needed to remove almost 2.5" of material however the metal machined easily so the lathe did not have to work to hard. Now that this side is done I can flip it over and mount it back up in the 4 jaw dial it in and machine out the other side. This one will be a little more complicated as I need to machine to better tolerances to allow me to thread it so that it fits onto the other part of the headstock. So here are some pictures of the process. The first picture shows the receiver on the left that the "nut" screws into, the nut and the blank I bought. Second picture has my sawn off blank ready for the lathe. Just so you see the third pictures shows where the nut threads into. Even after cleaning and some honing of the stock it is still hard to get the nut into the receiver and to start the thread. I'll have to be real careful when I machine this areas as the tolerances must be very close. Fourth picture is on the lathe part way through the boring process, and the fifth picture shows the one half of the blank all done with the original nut laying beside it.
Now all we need to do is as mentioned earlier rotate the piece in the chuck and machine out the other side. Hopefully by this time next week it will all be done and I can report success.
So until next week enjoy yourselves and congratulate your athletes who are over at the Winter Olympics. I wish them all the best and Go Canada Go.
Harold
Sunday 2 February 2014
Well Mother nature and the medical community conspired against me. Had planned on being at Mom's place this weekend into next week however with winter storm warnings on Saturday as well as this coming Tuesday and Wednesday decided not to risk the travel as I need to be back on Wednesday morning to allow the Hospital staff to draw some blood for testing. Oh well I'll have a chance to visit Mom in March when I go to part time status for my last month in the Military. However staying home allowed me to do some more work on the Overhead drive which we'll talk about now.
First I finished mounting the casting. I noticed during testing that if the casting was tight against the upper plate then the lower leg came at an angle to the lower plate. By inserting a couple of 1/8" spacers between the upper plate and the upper casting arm it now allowed the lower casting arm to be flat against the lower plate. So first thing we did was take some flat stock and make two spacers. Once they were done we placed them on the studs and hung the overhead casting. I then quickly drilled my extra hole in the casting and into the plate. Removed the casting so that I could remove the plate and finish drilling the hole and then tap the hole with 1/2" by 20TPI for a Hex bolt. Once that was done we reinstalled the plate and reinstalled the casting for hopefully the last time until we need to disassemble for moving. Here are a couple of pictures showing the two spacers being made and then the plates and spacers awaiting the casting. As well there is a picture showing the final mounting with all bolts installed.
Once the casting was installed it was time to start putting it all back together. First thing we installed was the transmission. This is a shaft with two sprockets on it that are engaged by a sliding mechanism that locks either of the sprockets depending on which way the slide is moved. Move it left you go to high gear move it right you go to low gear. I had spent some time earlier making sure it was all cleaned up and ready to be installed. When doing this I also adjusted the locking tabs on each side of the slider to ensure positive lock when gear engaged. I discussed this in an earlier installment. When I reinstalled it I added one new oilite washer since the old one looked worn down and badly scored. In the pictures below you will see it on the left side as being a little oranger than the rest. Otherwise all the rest of the original parts looked in good shape. Once the transmission was installed I could install the shifter arm and it's bracket. Here are some pictures showing these items. First picture is a close up of the transmission showing the two sprockets and the slot where the selector arm rides that moves the sleeve left or right. Second picture shows the complete assembly with the selector arm installed. The bottom two pictures show the selector arm from front and side view.
When I disassembled the Overhead drive to clean it we found that the two end caps of the transmission had a paper gasket underneath them. So bought some gasket paper and carefully cut some gaskets to match. Installed them under the caps before final assembly. After they were tightened down I carefully cut away the protruding parts so it became a nice clean install. Here is a picture showing some of the gasket sticking out before trimming.
First I finished mounting the casting. I noticed during testing that if the casting was tight against the upper plate then the lower leg came at an angle to the lower plate. By inserting a couple of 1/8" spacers between the upper plate and the upper casting arm it now allowed the lower casting arm to be flat against the lower plate. So first thing we did was take some flat stock and make two spacers. Once they were done we placed them on the studs and hung the overhead casting. I then quickly drilled my extra hole in the casting and into the plate. Removed the casting so that I could remove the plate and finish drilling the hole and then tap the hole with 1/2" by 20TPI for a Hex bolt. Once that was done we reinstalled the plate and reinstalled the casting for hopefully the last time until we need to disassemble for moving. Here are a couple of pictures showing the two spacers being made and then the plates and spacers awaiting the casting. As well there is a picture showing the final mounting with all bolts installed.
After bolting the top two nuts there was still a very slight gap between the bottom right casting and the plate in that location. So since the casting has threaded inserts to adjust to the lathe body I needed to thread this one insert out a little to compensate. However with the casting installed on the studs I needed a special little tool with two nubs on it that would go over the stud and match the indents on the insert. So we bought a 11/16" socket which was close to the right diameter, cut and ground the top to get two nubs and then filed a little of the outside diameter so it would sit over the stud and into the area of the insert. Grinding out the inside of a hardened socket is not easy. However got it done so that we could thread out the insert. Here's a picture of the socket being modified. Once it was done it worked quite well.
You'll notice in the above picture that only two screws are installed. When the assembly came to me it was missing some hardware. This was part of it. So over to the #39 lathe and carefully machined two replacement screws to match the ones that were missing. Here is a picture showing original screw and newly made one.
Pretty close match however mine is a little bit longer. This is not an issue as there was more hole than original screw. These were 5/16" by 26TPI screws. I still have to make two 1/4" by 26TPI screws for the bracket at the top of the casting that holds the selector arm to the casting. You can see the bracket on a previous picture of the transmission on the top of the casting. I'll do those tomorrow when I get back to work on it. After the two screws were made installed them in the caps one per side and installed the Gits oil caps at the same time. Heres a picture showing the screws installed along with the screwdriver malfunction mark on the casting which I'll have to touch up when I get the spray can out next time.
Well that's all for this installment. For those football fans out there I hope you enjoyed your Superbowl parties. I won't be watching the game however I will be checking out the commercials when they come on Youtube. Until next week stay warm and enjoy life.
Harold
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