South Bend thread dial

Mark_f

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A little while back, I posted an easy build for a thread dial for the 9 inch South Bend lathe. We'll, I am making another one that will look more like the factory one. There are and will be many more photos on my web site. I am posting the gear here because it always seems to be the biggest problem making your own dial. So here goes. If anyone needs more info, let me know.

For those of you who want to make your own thread dial for your lathe, the gear is always the problem, today I successfully made a nice quality gear very simply. I got the idea from a similar setup I saw on the net. I made this little contraption in about an hour to see if it worked. It works nicely , so I will probably make a better one. It is simply a means to hold an aluminum gear blank and index it accurately. I'm attaching photos here so anyone can copy it. I ground a 1/4 " square HHS tool to cut a 29 degree , 8 TPI acme thread and put it in a boring bar and fly cut the gear teeth on my Burke mill. I will be making a whole write up on this on my private web site. I am also going to machine a body similar to the SB version over the next few days. If anyone wants , I will post that process also. The nice part of this is this gear has cost nothing to make. Everything is from my scrap box. Any questions , just ask.

Mark

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Very cool indexer, nice job. Always great to see different approaches to problems.
 
somehow..someday...seeing the way you did that will assist me with something....

well done
 
Would love to see the write up.


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I am working on it now. I want to show how you can make a good quality thread dial similar to the original for next to nothing. The thread dial I made in my other thread works great , but for lack of a better description, it is kind of modern looking. This doesn't affect its operation but just looks "out of place" to me , so I am going to try and make one closer to the original style. It will take some time as I took on a job for a couple weeks and it really digs into my shop play time.

Mark

Would love to see the write up.


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I am working on it now. I want to show how you can make a good quality thread dial similar to the original for next to nothing. The thread dial I made in my other thread works great , but for lack of a better description, it is kind of modern looking. This doesn't affect its operation but just looks "out of place" to me , so I am going to try and make one closer to the original style. It will take some time as I took on a job for a couple weeks and it really digs into my shop play time.

Mark

Excellent! Take your time. I understand. I'm pretty much a weekend warrior in my shop...


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This is the write up I have started so far on this thread dial.

THREAD DIAL FOR SOUTH BEND 9 INCH LATHE


A little while back I posted a thread building a thread dial for my South Bend 9 inch lathe. I made a decent thread dial and it works just fine, but it is kind of “modern” looking ( for lack of a better word) and to me it kind of looks out of place. It is a nice thread dial, but I desire one that looks more like the original style that south bend used. The first thread dial was made from my scrap box and cost nothing except the $1 dollar I paid for the plastic gear.
thread dial completed.jpg This is the first thread dial. Threaa dial on lathe.jpg See what I mean about it looking “modern” ?


I am starting a new thread dial that is going to be closer to the original style used by South Bend. I will be using only scraps and items I have on hand, so this thread dial will hopefully cost me nothing. The main purpose of this project is to show how even with limited resources you can have quality tooling.


I started with the gear as it is the main problem for the home machinist, trying to obtain a decent quality gear. I started by making an aluminum blank for the gear that I made on my lathe. It is about the same dimensions as the original South Bend gear. I next made a little fixture to hold the gear blank and index it to cut the teeth.
image.jpg This is the fixture I made from scraps to make the gear. I used a 32 tooth plastic gear ( the same as the one I made the previous thread dial with) as a pattern for indexing.


image.jpg Here , I am fly cutting the teeth in the gear. The fixture is set at a 3 ½ degree angle on the mill table to get the angle on the teeth for a better fit on the lead screw.


The next two photos are of the finished gear.
image.jpgfinished gear 2.jpg


Now that I have a nice quality gear that fit’s the lead screw nicely, it is time to start making the thread dial body. I drew a basic print based on photos of a factory thread dial and measured the lathe to figure out the needed dimensions.


aluminum blank for thread dial.jpg I found a chunk of good quality aluminum large enough to make the body.


turned OD and gear pocket.jpg I first turned the bottom O.D. and bored the recess for the gear.


machining thread dial body.jpgmachining thread dial body1.jpg Next I roughed out the thread dial body.


thread dial body and gear.jpgThis is the roughed to size thread dial body and the gear.thread dial body roughed out.jpg


Tomorrow I will do some of the finish work on this body.

Mark

thread dial completed.jpg WP_20141027_18_26_28_Pro.jpg image.jpg image.jpg image.jpg finished gear 2.jpg aluminum blank for thread dial.jpg turned OD and gear pocket.jpg machining thread dial body.jpg machining thread dial body1.jpg thread dial body and gear.jpg thread dial body roughed out.jpg Threaa dial on lathe.jpg thread dial on lathe2.jpg
 
Lot of progress today.

The next step will be to do the finish milling on the body. First it is set up in the mill and .400” is milled off one side creating the front of the body.

milling flat.jpg Milling the front of the body

completed milling flat.jpgThis is the body with the flat completed.


The next step will be to mill the 45 degree angle at the top.

milling angle.jpg

completed cutting angle.jpgThis is the angle completed .

I was going to use the rotary table to shape the top, but it seemed like a lot of work setting up, so I used my belt sander to shape the top and polished it .



complete body and gear.jpg
 You can just see the shape of the top in this photo.


I was originally going to try to carve the body and support block as one piece but it would have been a lot of fancy complex machining. I want to keep this simple enough for anyone to make. So, I decided to add the support block as a separate piece. This meant milling a flat on the side of the body to bolt the support block to.
body showing support block notch.jpg





support block.jpgThis is the support block to mount to the notch I cut on the body.


The next photos show the body and support block together and test fit on my lathe.

test fit on lathe.jpg test fit on lathe 2.jpg


 It fits really well and I think it looks much better. Even though I like shiny polished metal, I think I will give this a coat of gray paint to match the lathe.

completed body and support block.jpg This is the complete unit except for the dial. I wanted a brass dial and I bored the body for a 1 inch dial, then found out my brass is only .900 diameter, so the dial will probably be a little fancier as I am thinking a two tone brass and aluminum dial. So far the cost for this project is $0.00 and I intend to keep it that way.


Mark


Will try to finish it up this weekend.

milling flat.jpg completed milling flat.jpg milling angle.jpg completed cutting angle.jpg complete body and gear.jpg body showing support block notch.jpg support block.jpg test fit on lathe.jpg test fit on lathe 2.jpg completed body and support block.jpg
 
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Subscribed! Well done!


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