10-12-2012, 04:53 PM
Hi,
Thanks for adding the lathe picture Big Al; like you I never throw drive belts away.
Your Lorch lathe looks a lot different to when I first saw it out of the back of your car David; it is delightful. At work we must have used miles of the round belting for powered conveyors; it used to be obtained in big rolls and as you describe it is simply cut to length and the ends heated before being quickly brought together to form an endless belt.
After going to so much trouble in obtaining the air con clutch the next step is how to fit it to the lathe?
These clutches I believe are directional in rotation it being clockwise so this limits my options for fitting. The motor I'm using has a very short shaft and this is 19mm diameter slotted with a key-way so leaves little metal to play around with. Had the shaft been longer I could have added the clutch directly to the motor. Unfortunately although this would have been the easy option I decided to install a counter-shaft.
The only other position now open to me is to locate the clutch on the counter-shaft directly connecting it to the mandrel via the drive belt. The original four stepped pulley speed arrangement is no longer required as the VFD will give variable speed over a much greater range; I would however like to retain both stepped pulleys and use them to power the counter-shaft thereby saving money in buying single pulleys.
Owning an engineering lathe or having access to one is a must; without; this project would immediately stop here. To have components turned professionally is a very expensive process and will deeply upset anyone as tight as me. I was once quoted £150 plus VAT to have a single headstock bearing turned from Tufnol this quote was from the Tufnol company. I turned both headstock bearings out of Whale Tufnol for under £20.
Now I had a big decision to make; the clutch had been mounted directly onto the aluminium compressor casing allowing the outer clutch plate shaft to revolve through its axis. The clutch plates both outer and inner needed to revolve but the energising magnetic coil needed to be fixed. I decided to turn a new mounting securing this with countersunk socket screws to a steel backplate.
I have a selection of material and chose steel for the new clutch mounting boss but it would be tight on diameter if I wanted to bolt rather than weld to the backplate. Measurements were taken directly from the original mounting using a digital vernier calliper and accuracy was called for as the clutch drum bearing and coil were interference fits.
The steel blank was cut to over length using my big Startrite band-saw. A band-saw can be very dangerous when it comes to cutting round material; whilst unsupported as soon as the moving blade makes contact it tries to turn the material just as a belt turns a pulley; this can catch a novice out and could result in loss of a finger or two. The round material must be prevented from turning and a simple way is to securely clamp two short lengths of timber to it as shown in the picture ensuring the clamp does not foul either the blade or guides. If a mitre guide is available then the round material can be clamped directly to this. Keep hands away from the moving blade at all times and use a push stick.
Cutting steel blank using Startrite band-saw.
Once cut to length a 3/4” diameter hole was drilled right through on axis; this was the largest bit my big drill would accept on its #2MT. The prepared blank could now be mounted in the lathe and brought to exact size. I was very fortunate here because my lovely wife Bron had just bought me a Clarke 300mm engineering lathe as a Christmas present; both my Myford's are still in kit form awaiting full restorations. It was interesting to use such a small lathe for the first time but with patience and light cuts it did a splendid job in fact I found using the Clarke most enjoyable and for once I was warm and comfortable in the workshop.
Turning blank and using boring bar.
Initially I intended to use 6mm socket countersunk screws because I have these in stock for mounting the boss to the back-plate. Unfortunately the outer diameter was not big enough to accommodate this but 5mm screws could be used. I visited Screwfix and bought 100 of these 5mm x 16mm stainless screws as they were cheap and useful to have in stock for future projects. There was just enough metal allowing these screws to be used without breakthrough at the edge or damage the accurately turned coil seating.
As usual whilst doing my projects the weather was dire it being a wet black hole outside making everything gloomy. I needed to very accurately space 6 holes around what I'll call the flange section. I've had great difficulty many times in trying to obtain accuracy and this proved a nightmare a few years ago whilst I was gear cutting so now was the time to find a better way than resorting to using my drawing instruments again; I truly detest wearing glasses but without I'm blind; these bi-focals test my patience and trying to read a protractor in the gloom was a pain. I've attempted to learn CAD (Computer Aided Design) many times over the last 14 years only to fail miserably. As the weather was so bad anyway I thought I would once again have a go at CAD and downloaded emachineshopCAD which is totally free. The story is covered in detail here;
http://golbornevintageradio.org/forum/sh...p?tid=2716&pid=29058#pid29058
The accurately cut out paper template was attached to the flange using double sided adhesive tape and a newly sharpened centre punch and hammer were used to “pop” the six hole centres before removing the template. The holes were drilled at tapping size but before tapping I now wanted to use this boss as a drilling guide for the backplate. The backplate is heavy steel section 70mm x 10mm. The backplate was marked for the boss centre and a 3/4” diameter hole drilled through; this hole was opened up to give clearance for the 7/8” diameter shaft. Now the boss could be secured to the backplate using a long bolt;nut and washers allowing the six holes to be drilled through the backplate. With the boss released the holes in the backplate were opened up to clearance for the screws but at this point I took extreme care not to open up the wrong holes. The boss holes were then tapped at 5mm.
Paper template attached.
The backplate was then countersunk at the holes on it's back face and at last I had a brand new clutch mounting in my hand. The backplate still requires cutting to length but the length is not yet determined due to our terrible climate; I'm simply fed up of working in these conditions. The workshop is now very comfortable but I have to visit the garage often to obtain tools and materials and I hate wrapping up like an Eskimo for each visit. Fortunately our winter only lasts nine months each year or it would depress me.
Secured to back-plate and socket screws.
I've made a start on the new counter-shaft this being 7/8” diameter. The diameter at one end has been reduced to exactly match the original shaft diameter as has the end section that will eventually be threaded at 9mm x 1.5mm to accept the securing nut. A key-way needs cutting but that is another job. The new shaft was right at the lathes extreme it being 12” long; as the shaft ends were not accurately centred I had to resort to using the fixed steady setting the shaft to run true before turning could commence. The tail stock could be removed for this operation.
Maximum length in lathe.
The clutch plate faces were very rusty the outer plate being worst. I cleaned up the inner plate using abrasive paper but the outer plate was proving hard work so I chucked it in the lathe and skimmed it.
Skimmed outer clutch plate.
It takes longer to write the story than to do the work but at least I'm giving step by step accounts of how this job is progressing; oh for some warm dry weather and fingers crossed this project turns out as expected.
Kind regards, Col.
Old and new clutch mounts and new steel clutch mount.
Thanks for adding the lathe picture Big Al; like you I never throw drive belts away.
Your Lorch lathe looks a lot different to when I first saw it out of the back of your car David; it is delightful. At work we must have used miles of the round belting for powered conveyors; it used to be obtained in big rolls and as you describe it is simply cut to length and the ends heated before being quickly brought together to form an endless belt.
After going to so much trouble in obtaining the air con clutch the next step is how to fit it to the lathe?
These clutches I believe are directional in rotation it being clockwise so this limits my options for fitting. The motor I'm using has a very short shaft and this is 19mm diameter slotted with a key-way so leaves little metal to play around with. Had the shaft been longer I could have added the clutch directly to the motor. Unfortunately although this would have been the easy option I decided to install a counter-shaft.
The only other position now open to me is to locate the clutch on the counter-shaft directly connecting it to the mandrel via the drive belt. The original four stepped pulley speed arrangement is no longer required as the VFD will give variable speed over a much greater range; I would however like to retain both stepped pulleys and use them to power the counter-shaft thereby saving money in buying single pulleys.
Owning an engineering lathe or having access to one is a must; without; this project would immediately stop here. To have components turned professionally is a very expensive process and will deeply upset anyone as tight as me. I was once quoted £150 plus VAT to have a single headstock bearing turned from Tufnol this quote was from the Tufnol company. I turned both headstock bearings out of Whale Tufnol for under £20.
Now I had a big decision to make; the clutch had been mounted directly onto the aluminium compressor casing allowing the outer clutch plate shaft to revolve through its axis. The clutch plates both outer and inner needed to revolve but the energising magnetic coil needed to be fixed. I decided to turn a new mounting securing this with countersunk socket screws to a steel backplate.
I have a selection of material and chose steel for the new clutch mounting boss but it would be tight on diameter if I wanted to bolt rather than weld to the backplate. Measurements were taken directly from the original mounting using a digital vernier calliper and accuracy was called for as the clutch drum bearing and coil were interference fits.
The steel blank was cut to over length using my big Startrite band-saw. A band-saw can be very dangerous when it comes to cutting round material; whilst unsupported as soon as the moving blade makes contact it tries to turn the material just as a belt turns a pulley; this can catch a novice out and could result in loss of a finger or two. The round material must be prevented from turning and a simple way is to securely clamp two short lengths of timber to it as shown in the picture ensuring the clamp does not foul either the blade or guides. If a mitre guide is available then the round material can be clamped directly to this. Keep hands away from the moving blade at all times and use a push stick.
Cutting steel blank using Startrite band-saw.
Once cut to length a 3/4” diameter hole was drilled right through on axis; this was the largest bit my big drill would accept on its #2MT. The prepared blank could now be mounted in the lathe and brought to exact size. I was very fortunate here because my lovely wife Bron had just bought me a Clarke 300mm engineering lathe as a Christmas present; both my Myford's are still in kit form awaiting full restorations. It was interesting to use such a small lathe for the first time but with patience and light cuts it did a splendid job in fact I found using the Clarke most enjoyable and for once I was warm and comfortable in the workshop.
Turning blank and using boring bar.
Initially I intended to use 6mm socket countersunk screws because I have these in stock for mounting the boss to the back-plate. Unfortunately the outer diameter was not big enough to accommodate this but 5mm screws could be used. I visited Screwfix and bought 100 of these 5mm x 16mm stainless screws as they were cheap and useful to have in stock for future projects. There was just enough metal allowing these screws to be used without breakthrough at the edge or damage the accurately turned coil seating.
As usual whilst doing my projects the weather was dire it being a wet black hole outside making everything gloomy. I needed to very accurately space 6 holes around what I'll call the flange section. I've had great difficulty many times in trying to obtain accuracy and this proved a nightmare a few years ago whilst I was gear cutting so now was the time to find a better way than resorting to using my drawing instruments again; I truly detest wearing glasses but without I'm blind; these bi-focals test my patience and trying to read a protractor in the gloom was a pain. I've attempted to learn CAD (Computer Aided Design) many times over the last 14 years only to fail miserably. As the weather was so bad anyway I thought I would once again have a go at CAD and downloaded emachineshopCAD which is totally free. The story is covered in detail here;
http://golbornevintageradio.org/forum/sh...p?tid=2716&pid=29058#pid29058
The accurately cut out paper template was attached to the flange using double sided adhesive tape and a newly sharpened centre punch and hammer were used to “pop” the six hole centres before removing the template. The holes were drilled at tapping size but before tapping I now wanted to use this boss as a drilling guide for the backplate. The backplate is heavy steel section 70mm x 10mm. The backplate was marked for the boss centre and a 3/4” diameter hole drilled through; this hole was opened up to give clearance for the 7/8” diameter shaft. Now the boss could be secured to the backplate using a long bolt;nut and washers allowing the six holes to be drilled through the backplate. With the boss released the holes in the backplate were opened up to clearance for the screws but at this point I took extreme care not to open up the wrong holes. The boss holes were then tapped at 5mm.
Paper template attached.
The backplate was then countersunk at the holes on it's back face and at last I had a brand new clutch mounting in my hand. The backplate still requires cutting to length but the length is not yet determined due to our terrible climate; I'm simply fed up of working in these conditions. The workshop is now very comfortable but I have to visit the garage often to obtain tools and materials and I hate wrapping up like an Eskimo for each visit. Fortunately our winter only lasts nine months each year or it would depress me.
Secured to back-plate and socket screws.
I've made a start on the new counter-shaft this being 7/8” diameter. The diameter at one end has been reduced to exactly match the original shaft diameter as has the end section that will eventually be threaded at 9mm x 1.5mm to accept the securing nut. A key-way needs cutting but that is another job. The new shaft was right at the lathes extreme it being 12” long; as the shaft ends were not accurately centred I had to resort to using the fixed steady setting the shaft to run true before turning could commence. The tail stock could be removed for this operation.
Maximum length in lathe.
The clutch plate faces were very rusty the outer plate being worst. I cleaned up the inner plate using abrasive paper but the outer plate was proving hard work so I chucked it in the lathe and skimmed it.
Skimmed outer clutch plate.
It takes longer to write the story than to do the work but at least I'm giving step by step accounts of how this job is progressing; oh for some warm dry weather and fingers crossed this project turns out as expected.
Kind regards, Col.
Old and new clutch mounts and new steel clutch mount.
Happiness is a wreck of a cabinet to restore.
