Group Project: Dividing Head - The Build

The concentricity of the shaft will matter as it relates to the index plates. I guess I should shoot to have the shaft dead center on the outboard end of the shifter body. At the nose (inboard) it will not be so important. So I will start drilling from the outboard side.
Robert
 
If i used the D bit i was thinking of using it as a specified hole size instead of boring depending on the size of the hole.
 
rwm said:
12L14 on the way:
View attachment 367281
It occurs to me that some of these parts are probably best done as matched set. For example, Erik is doing the spindle. To get a close tolerance on the spindle nut is going to be hard without measuring the spindle threads over wires and having a go/no go gauge for the nuts. If you are making both parts then matching the threads by trial with the nut is much easier. If there is slight variation in the spindle threads you might want to have matched pairs that stay together. I suppose if Erik nails every spindle to be identical or we accept a lower class of fit on the nut it could work out. Thoughts?
Non threaded mating parts are easier. I will ream the bore of the shifter so as long as the worm shaft is <9/16 it will go.
Robert
Click to expand...

I bought 2 different new (different manufacturer) 1-1/2”, 12 tpi nuts on eBay AND a Shars 1-2” screw thread micrometer for this project. These all arrived yesterday.

After I have completed the work, the nuts will fit neither too loosely nor too tightly on all 8 spindles. If not, I will remake the spindle. I’m gonna sneak up on it!

A few years ago, I purchased some eBike axles from Zelena Vozila in Zagreb, Croatia; one of the axles had the the M16 threads too loose (i.e. wobbly) on one side. Come on now; don’t ship out scrap! You have to remake the part in this case.

If for some reasons my 2 sample heavy hex nuts are manufactured significantly different from each other, I will post that development here.

I am going to start work on the spindles this Sunday + Memorial Day. I have 4 lengths of 12L14 on hand now.

Moving forward, I can spend all day every Sunday until these are done. I will make every effort to put in a few hours on Saturday mornings, also. My work weeks are a whopping 67 hours.

BTW one supplier sells these heavy hex nuts for only $3.20 each. Should I spring for 6 more nuts so that everybody receives a nut on their spindle? I don’t mind; just say the word (quickly, lest they sell out). I would think that you guys would want to scrutinize the fit. I know I would!

F4D33BDE-CF30-4D5E-8917-BC32412B703C.png
 
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  • Wow
Reactions: rwm
I got my part drilled an reamed:

1622226265301.png

The long mark is the high point of the eccentric. Jeff must have known my SB lathe has 3" travel on the tailstock when he designed this 3.14" part!
Next question: I have been reading about the difficulties for press fitting small dowel pins in blind holes. The tolerances are tight and the air has to go somewhere. Are there any objections to drilling out to 1/8" and using red Loctite?

Dowel Pin basics

Newbie question here, let me see if I understand this correctly I am making a jig to hold a part to contour mill with some 1/2" alum tooling plate. I am going to use .125" dia. dowel pins for alignment so I figure I will drill the holes with a #31 (.120") drill then ream with a .1247" reamer...
www.practicalmachinist.com

Otherwise should I use an oversize pin and a .1250 reamer or a .1250 pin and an undersize reamer? I have none in stock.

I think I am going to have to use my bolt hole calculator to drill the hub. Not sure how to hold this piece yet. It is kind of tall to hold in the mill vise with a V block.

Robert
 
rwm said:
I got my part drilled an reamed:

View attachment 367464

The long mark is the high point of the eccentric. Jeff must have known my SB lathe has 3" travel on the tailstock when he designed this 3.14" part!
Next question: I have been reading about the difficulties for press fitting small dowel pins in blind holes. The tolerances are tight and the air has to go somewhere. Are there any objections to drilling out to 1/8" and using red Loctite?

Dowel Pin basics

Newbie question here, let me see if I understand this correctly I am making a jig to hold a part to contour mill with some 1/2" alum tooling plate. I am going to use .125" dia. dowel pins for alignment so I figure I will drill the holes with a #31 (.120") drill then ream with a .1247" reamer...
www.practicalmachinist.com

Otherwise should I use an oversize pin and a .1250 reamer or a .1250 pin and an undersize reamer? I have none in stock.

I think I am going to have to use my bolt hole calculator to drill the hub. Not sure how to hold this piece yet. It is kind of tall to hold in the mill vise with a V block.

Robert
Click to expand...

Nice chamfers!
 
Erik- I hope you didn't pay $28 in shipping on those nuts?! I hate when eBayers try to make all their margins on shipping.
Robert
 
rwm said:
Erik- I hope you didn't pay $28 in shipping on those nuts?! I hate when eBayers try to make all their margins on shipping.
Robert
Click to expand...

I saw that & I didn’t complain about it. However, the shipper noticed it and he threw $6 cash in the box.
 
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