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Smart and Brown 1024 tachometer (from S&B insert tooling)

I looked at the video again and the only dimension I have is the larger outer diameter of 3.75". If you could give me any critical dimensions ( I don't need a good drawing, just some measurements ) I would appreciate it. the inner shoulder locations and depth of bores would be good as well as the smaller outer. Thanks a lot for the trouble. We S and B guys are a small group. The new groups I.O. for S and B is just getting started but you would be a great source. Dave
 
I looked at the video again and the only dimension I have is the larger outer diameter of 3.75". If you could give me any critical dimensions ( I don't need a good drawing, just some measurements ) I would appreciate it. the inner shoulder locations and depth of bores would be good as well as the smaller outer. Thanks a lot for the trouble. We S and B guys are a small group. The new groups I.O. for S and B is just getting started but you would be a great source. Dave

OK - I will try to have a look at this tomorrow.
 
This is my drawing of the drawtube collar:

Drawtube Collar.jpg

A few notes on the drawing.

Most of the dimensions are essentially open limits.
The only exceptions are:

1)The internal bore of 1.875", which must be a close sliding fit on the end of the spindle. I suggest you measure yours and make sure that you get this fit right.

2) The depth of the 2.745 bore and the position of the set screw holes. This must match up with the position of the groove that the set screws engage.

3) The 2.745 bore should be a good fit on the grooved collar.

It may be that you don't have this part with the groove; I can't really see from your photos. If you don't have it let me know, because you will need to replicate it.

I don't understand the purpose of the internal 1/16 fillet radius. This appears to be just clearance over the snap ring on the end of the drawtube. If that is the case then you could just make the bore square.

The set screws are 2BA. You could of course replace these with a local US thread, but since all the rest of the threads on this lathe will be BA or Whit (or in my lathe, metric for some leadscrews!), you might want to avoid confusing subsequent owners. The set screw end must snugly engage the groove so don't stray too far from the 2BA diameter.

This part could be made of any available steel. It is heavily over-engineered for the job it has to do.

I have the CAD model I made for this drawing if you have the means to use it.

I hope that helps and I haven't missed anything significant. If I have let me know.
 
This is my drawing of the drawtube collar:

View attachment 312917

A few notes on the drawing.

Most of the dimensions are essentially open limits.
The only exceptions are:

1)The internal bore of 1.875", which must be a close sliding fit on the end of the spindle. I suggest you measure yours and make sure that you get this fit right.

2) The depth of the 2.745 bore and the position of the set screw holes. This must match up with the position of the groove that the set screws engage.

3) The 2.745 bore should be a good fit on the grooved collar.

It may be that you don't have this part with the groove; I can't really see from your photos. If you don't have it let me know, because you will need to replicate it.

I don't understand the purpose of the internal 1/16 fillet radius. This appears to be just clearance over the snap ring on the end of the drawtube. If that is the case then you could just make the bore square.

The set screws are 2BA. You could of course replace these with a local US thread, but since all the rest of the threads on this lathe will be BA or Whit (or in my lathe, metric for some leadscrews!), you might want to avoid confusing subsequent owners. The set screw end must snugly engage the groove so don't stray too far from the 2BA diameter.

This part could be made of any available steel. It is heavily over-engineered for the job it has to do.

I have the CAD model I made for this drawing if you have the means to use it.

I hope that helps and I haven't missed anything significant. If I have let me know.

Thanks. the only other measurement I can think of is the distance from the collar to the end of the bar. I have been told it is 515mm or 20.28". If yours matches that or is slightly different, I'd appreciate a good measurement. Mine is off a picture so there is some distortion.

I usually change the 3/16-32 or even the 2BA if I can to 10-32. The sources for English screws here in US is often India and that stuff seems undersized. I've ordered screws for my dickson holders and they all fit loosely. In fact, the BSW fit my UNC which shouldn't happen, particularly in a set screw application. Dave
 
The distance from the flat face of the collar to the end of the screwed portion of the drawtube is 20.25" on my lathe. I do not think this needs to held with any precision, but if it was a long way short it might result in over-stressing the collet thread.
 
I took the bar apart and the thrust bearing is good. I cleaned up the brazing. The extra washer is to pinch the bearing against the spindle to secure the collet. It works but not as it should be so I'll make a replacement. Thanks, Dave
 
I think making a new grooved collar is the right thing to do. If you have just a washer, the large collar will probably not extract when you pull the drawtube out of the spindle. You can take it out afterwards but it is not as convenient. The other consideration is alignment. The heavy collar should be located on the spindle and on the handwheel assembly. If it was just located on the spindle it might well rattle around a bit and that is not something you would want with something that heavy at a couple of thousand rpm.

I think the design of the grooved collar is self evident but let me know if you need dimensions.
 
I should be good. The bore on the bearing end should be more shallow so the collar doesn't seat on the wheel, the the bore on the other end needs to clear the 1.875 spindle.

I see why you mounted the tach reader back there so I may try to do something similar. Keeps it out of the way. i had planned to put the display on the DRO but mounting in the back allows it on the front panel assuming I have the room. Dave
 
I should be good. The bore on the bearing end should be more shallow so the collar doesn't seat on the wheel, the the bore on the other end needs to clear the 1.875 spindle.

Yes that is correct.

I see why you mounted the tach reader back there so I may try to do something similar. Keeps it out of the way. i had planned to put the display on the DRO but mounting in the back allows it on the front panel assuming I have the room. Dave

If you take the end cover off you get very good access and a nice flat casting to attach the optical sensor. Very easy to get everything set up with just the right clearances. You can run the cable out the back of the headstock via a hole which just happens to be there. Alternatively I think you could go through the electrical enclosure that normally has the Crabtree reversing/starter box in it.
 
I looked at the draw bar collar and have a couple more questions. My bar was remade and i suspect the length changed making the collar non functional. The 1.875 bore into the spindle depth seems critical as it is what pulls the collet to the bar. The distance from the back of the wheel to the end of the bar is 21.875 but the distance to the face of the collar is 20.25 making the collar 1.375 or slightly less in thickness. That looks less than the original. Can you verify and also give me the depth of the 1.875 bore as the distance from that shoulder to the end of the bar is what I want to verify.

I don'r understand why S and B made the large hole with the chrome ring on the end of the headstock, only to fill it with the large diameter collar. A 2" hole would have worked as well and saved a block of steel. thanks, Dave
 
I'm happy to make some measurements for you, but I'm not really clear what dimensions you need. The depths of the 1.875 and other collar bores are given on the drawing I made. Possibly you need the overall length of the small collar with the groove that engages with the set screws? If so maybe the best thing would be for me to dismantle that part of the drawtube and make a drawing of it. Or maybe it is the drawtube itself that you need? A sketch would clarify.

Provided that the drawtube is able to engage the threads of the collets and then pull up for a few turns before bottoming out, you should be fine. If it can't do this then certainly there is a problem to resolve. There is no need for great accuracy in this area.

The large size of the hole in the LHS headstock cover is possibly a result of wanting to have plenty of design versatility. There is a keyway in the left hand end of the spindle that is obviously intended for something but I'm not sure what. I seem to recall that there was an optional 5C lever closer that could fit in there and that would probably have needed the larger diameter and perhaps the keyway. If you are really curious, try Bracehand - they probably know the answer, and might even sell you a lever closer if you can stand the prices.

My 1024 does not have chrome rings. They can look shiney but mine are just polished Aluminium alloy.
 
I had forgotten that you included that drawing. It came through so small in the text i missed it. That should be all I need. I believe my bar is 1/8-3/16 shorter than the original and was concerned that shortening the collar would take too much steel off the 1.875 shoulder. Your depth of .5" is a little less than a measurement I had for a square head bar and the distance between the 1.875 shoulder and the 2.75" shoulder looks to be in the .5" range so I should be able to reduce the length and still have at least .25-.35" of steel. The distance from the recessed shoulder to the end of the bar is the critical dimension for me.

Chris Hallybone has been a great help and the prices have been reasonable but he is hard to contact. I wondered about the key in the spindle. I've never seen anything but a wheel on a 1024. Thanks, Dave
 
Hi billmac
Could you send me a pm please. Tried to pm you, but your inbox is full. Just a query about something you posted on another thread and this thread is one of your more recent posts I could find.
Many thanks
Gary
 
What did you use for the optical tape? How many divisions did you use? I've got a tachulator with rpm and sfm. Thanks, Dave

Assuming that this question is directed to me -

I didn't use an optical tape. I just painted a convenient flange face on the spindle into gloss white and matt black sectors. This works perfectly with the optical transducer I used. This transducer is refective rather than transmissive, meaning that it contains a LED that sends out light and has on the same plane a photo-transistor that picks up the light reflefcted back. Possibly your tachulator expects to use a sensor where the LED light needs to pass through an optical tape and then be picked up on the same axis on the the other side of the tape? That would be much harder to use for a lathe spindle if this is the case.

In my first attempt I used one white, one black sector (i.e. just divided the periperal into two parts). This worked fine for higher spindle speeds but would cause a wandering read out at lower speeds. After a bit of thought and some sums I decided that the signal rate was too low to get a steady read out so I repainted it into 6 sectors and adjusted the tachometer to get the correct calculation. That worked well at both low and high speeds.

These days I feel much more confident with microcontrollers than I was when I first fitted this tachometer. It is really quite easy to build your own tachamoeter from scratch without using a kit and then you can get all the facilities you want without compromise and at a very low cost.
 
Thanks, Bilmac. Here is my set up. The flange could serve for the reader if the four holes don't mess up the readings. I think the flange is also the bearing adjustment. There is a set screw that was loose but the flange had not loosened up. I could also put a second ring with a 2.875+ ID and paint that to avoid messing with the adjusting flange. DaveDSCN3980.jpgDSCN3981.jpgDSCN3984.jpg
 
I've much enjoyed your dialog about your S&B 1024's. I have a '63 round head, which is pretty much original. I'm running my shop via a PhasePerfect, the machine is 240V, so the power up was pretty straight forward. There were some minor repairs, and the usual cleaning - but I really like the machine. The main annoyance is that the brake has been gutted. The brake on mine was different than the one you have shown (which aligns to what is in the documentation). Mine was a disc. The disc was still present, but the actuator is gone. I agree a VFD would be a nice upgrade - but the original configuration is very good (nice to have the 6 speeds of shift on the fly). I'm jealous that the VFD also makes it easy to brake the spindle. I struggle to change the existing drive to VFD, just to get a braking resistor.

Did either of you end up with the rear tool post? The sales pamphlet has a thumb nail image - it doesn't look to tough to make (waiting for a rainy day). Do either of you know if there was an official platform over the headstock or tailstock? Anyway, I like what you guys have done with your machines. Regards, DavidC

DSCF4262.jpgDSC02893.jpgDSC02385.jpg
 
Craig, when you say platform over the headstock do you mean a shelf that bolts over the top? Mine has one of those. I don't have the second post but have an Algra ( dickson clone ) and an extra Multifix A if you need a second.

My brake was not original and didn't work well. The three speed motor was wound 550 and had issues which required a rewind or a new motor. If yours is good, keep it and find a brake solution. There is a motor for sale in the UK and maybe you can negotiate for the brake. A vfd with the existing motor isn't ideal. There are two separate windings and a Dahlander connection for the third speed, 6 pole separate, 4 pole with 2 poles kicking out. If you were to wire a vfd, you would want to program for the 6 pole and the 4 pole and avoid the Dahlander. You would have to run the middle speed at 120 hz though. DaveDSCN3401.jpg

PS, I do have the spare motor, some Matrix clutch parts, a Santon switch and original buttons if you need stuff. Dave
 








 
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