Atlas 618 Thread Chasing Dial Drawing

The critical dimensions are the bore for the shaft, the perpendicular mounting hole, and the relationship between the two is the distance from the mounting hole to the lower end of the shaft bore. I can pull mine off my Atlas/Craftsman 6x18 and make some measurements. The tough one will be the gear. It is a 32 tooth gear with a profile to fit the Acme thread of the lead screw. Roughly measuring the diameter pitch, the o.d. measured .675" and the d.p. calculated to 50.37 which is not a standard pitch so a custom cutting tool would need to be made to cut the teeth. There was a method for cutting gear teeth using a slitting saw floating around recently. The width of the blade would need to be .027" o thinner to cut the root of a properly profiled tooth but since there is essentially no load on the gear, you could get away with a simple straight cut on the diameter with a .032" width blade.

Let me know if you want to proceed and I will disassemble mine and blueprint it.

The Clausing parts numbers for my lathe are:
threading dial assembly, 3950-18
dial, M6-62
body, threading dial, M6-63
gear, M6-64A
shaft, M6-65
 
RJSakowski said:
The critical dimensions are the bore for the shaft, the perpendicular mounting hole, and the relationship between the two is the distance from the mounting hole to the lower end of the shaft bore. I can pull mine off my Atlas/Craftsman 6x18 and make some measurements. The tough one will be the gear. It is a 32 tooth gear with a profile to fit the Acme thread of the lead screw. Roughly measuring the diameter pitch, the o.d. measured .675" and the d.p. calculated to 50.37 which is not a standard pitch so a custom cutting tool would need to be made to cut the teeth. There was a method for cutting gear teeth using a slitting saw floating around recently. The width of the blade would need to be .027" o thinner to cut the root of a properly profiled tooth but since there is essentially no load on the gear, you could get away with a simple straight cut on the diameter with a .032" width blade.

Let me know if you want to proceed and I will disassemble mine and blueprint it.

The Clausing parts numbers for my lathe are:
threading dial assembly, 3950-18
dial, M6-62
body, threading dial, M6-63
gear, M6-64A
shaft, M6-65
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Hello, I appreciate your offer very much. I will let you know. Thank you.
 
Alberg30 said:
Hello All, I purchased an Atlas 618 lathe a while a go. Was stored in a barn for more than 30 years waiting for a new owner. Was pretty rusty but it cleaned up very nicely with very little wear. The only issue i have is that the thread chasing dial is missing,
Does anyone here know of or have a drawing the assembly that i could manufacture one from? I know its not a big issue to make one without a drawing, but a drawing would make things easier.

Any info will be greatly appreciated.
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I posted a couple of pics. The machine was pretty rusty but cleaned up pretty good>
 
cross thread said:
If it were me , I would just buy it from antfarm , $40 is not that bad from him . What tooling and accessories did your lathe come with ? Welcome to the forum .
Mark .
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Hello, I will check that out. The machine came with all of the change gears, I do not believe they were used much or not used at all, There is a nice little four jaw chuck made in England. Did not get the face plate, Im not sure what came with the standard machine. Came with a sturdy steel bench also. I think it has the original motor, The type with the oilers. I have disassembled the machine completely, There is very little wear on the bed. All of the bearing surfaces are basically like new,
 
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I reverse engineered my thread dial. The gear is a 32 tooth with 50.266 diametral pitch and 14.5 pressure angle. Good luck finding a gear hob for that. I would grind a single cutter to cut it or use a slitting saw to approximate it. The rest of the parts are fairly simple.
618 Thread Dial 1.JPG
618 Thread Dial 2.JPG
 

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RJSakowski said:
I reverse engineered my thread dial. The gear is a 32 tooth with 50.266 diametral pitch and 14.5 pressure angle. Good luck finding a gear hob for that. I would grind a single cutter to cut it or use a slitting saw to approximate it. The rest of the parts are fairly simple.
View attachment 429257
View attachment 429256
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Hello RJ,Thank you for taking the time to do this. I do appreciate it a lot. I will let you know how i make out with the dial.
 
If you decide to make the gear, you can get a fairly good approximation with a vertical RT and a slitting saw. Basically, you would set up the RT vertically and cut the center of each gullet. then you would offset the RT slightly and rotate the RT slightly to cut the upper sides of the tooth. You may be close enough with 4 cuts per tooth. 6 cuts should give you a near perfect tooth.
www.hobby-machinist.com

Making any sized gear with just a slitting saw....

Pretty cool video.
www.hobby-machinist.com www.hobby-machinist.com
 
Alberg30 said:
Hello, I will check that out. The machine came with all of the change gears, I do not believe they were used much or not used at all, There is a nice little four jaw chuck made in England. Did not get the face plate, Im not sure what came with the standard machine. Came with a sturdy steel bench also. I think it has the original motor, The type with the oilers. I have disassembled the machine completely, There is very little wear on the bed. All of the bearing surfaces are basically like new,
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Sounds like you are going to have fun with this machine . As far as what came standard with the machine , I'm not sure anything did . Here are the things that were offered . http://www.lathes.co.uk/atlas-6-inch-lathe-accessories/
Also here is a good read . http://www.lathes.co.uk/atlas6inch/
Mark .
 
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