A Dividing Head Anyone Can Build

[Mark_f]

Mark-this is awesome! A great design and it looks great too. I'm not entirely sure this is a dividing head that "anyone" can build. You just have the skills to make it look easy! Nevertheless I may give it a try. But I'm not makin' no 0.008 shims!
R

Thank you, but I bet you can do it.

The first thing to realize is that you can do anything if you take it piece by piece. Everything is common sense if you break it down into smaller pieces. More so when I was younger, someone would say to me " can you fix this?" or " can you make this?" .. I would say " sure... no problem". And I may have never seen the thing before in my life. but I just looked at things as small individual pieces or projects and it was easy to comprehend. Sometimes I hit a bump like snapping the tap in a part that would take many hours to replace, but you just sit back, look at the options and work through it.

When I was in my twenties, I worked in a building with a water powered elevator. It was powered by a 20 foot long piston cylinder 30" in diameter and used packing for rings. It had pulleys galore and what seemed like a mile of cables. This thing was leaking badly. I had never in my life seen a contraption like this. It was made in 1902. my boss said " can you fix it?'. I said "sure". When he came back that elevator piston, pulleys and cables and parts were scattered all over the basement. He said " I sure hope you can put that back together." I looked dumbly at him and said " me too". He never came back and I had it running by the end of day. Everyone that saw that mess still laughs about it 40 years later.

I guess what I am saying is... I always thought I can fix or do anything and I been doin it for over forty years. ( I slowed down a lot though).

If you think you can't ...you won't.... but if you try you most often succeed.

I see so many talented people on here say " I don't have the skills to do that" but they do good work.

 

[jeff_g1137]

Mark-this is awesome! But I'm not makin' no 0.008 shims!
R

Hi
If you go for 1/8" end play, you can make a 1/8" washer.

 

[rwm]

That's closer to the tolerances I am capable of....
R

 

[Silverbullet]

Wow I've been thinking about making my own too. This is great I was looking for a right angle gear drive from a motor or from a snow blower gear box . In the works another project when I get time . Thanks loads

 

[Mark_f]

I started to work on the front index plate. It will have 24 holes for direct indexing which will cover many of the common needs for divisions. I set the plate up on my rotary table which reads down to 5 minute increments and this will be plenty accurate. I used a small center drill to start the holes . This was done to prevent drill flex or walking and preserve the accuracy.


After going around and starting the holes, I next drilled them through with a new sharp .125 drill. Now I have an accurate row of 24 holes in the front index plate. They were a little snug fit on a .125 dowel pin so I ran a .125” reamer in each hole for a good sliding fit. This process took a couple of hours but is the best way to insure the quality desired.
Next the plate was put in the 4 jaw chuck on the lathe and 360 graduations put on the outside edge to mark the 360 degrees. This was an extra feature I thought might come in handy.

After the graduations , I stamped the numbers for the degrees. This photo is the setup to stamp the numbers This is all on the edge of a .250” thick disc. And surprisingly it is very easy to read and looks good.



I drilled and reamed a hole in the plate and the spindle flange for a .125 dowel pin. The dowel pin is pressed into the flange and secured with lock-tite bearing mount paste. This pin locates the plate and keeps it from turning.
This is the finished index wheel installed.


I milled a handle bar for the worm shaft. This will hold the handle and the index plunger. It was milled from 5/16” thick aluminum bar 1” wide and coated with the black wrinkle finish.
Here the handle bar is installed . The handle and index plunger will be made from brass.

The last item done today was I made a brass pointer to indicate the position of the dividing head body.

Tomorrow I will start the tedious task of drilling the index plates. There will be three or four rows of holes on each plate and I have three plates. I have been using Shop Calc to work out the rows of holes needed and they will cover all divisions up to 50 and many over that.

Mark Frazier

 

[Mark_f]

I made the spindle lock today. I started by placing the entire dividing head on the mill table and milling the mounting surface square and parallel with the spindle. This is important because there is only .005" clearance on the lock and the spindle has to turn free when unlocked. This was the reason I left this flat area when I made the worm mounting plate.


Next , I turned a hole in a piece of .375" aluminum plate .005" larger then the collar on the spindle. I then milled the lock plate and slit one side for a clamp bolt.

The plate is installed on the dividing head. A perfect fit.

A "T" handle was made by modifying a long bolt. The handl sits 2 inches above the lock to make it easy to access.


I also started to make the index plates.The plates have .125" holes. To get the most accuracy, the holes are spot drilled with a small center drill. Then they are drilled with a newly sharpened .125 drill bit. My rotary table reads to one minute divisions. To lay out the holes that do not divide evenly into 360 degrees ( such as 21 holes which is a hole every 17.14286 degrees), I converted the decimal degree number to degrees, minutes, and seconds. I then moved my rotary table to each position as accurately as it will read ( which is 1 minute divisions. this makes a very accurate plate and the accuracy is enhanced by the use of the 30:1 gear ratio.
The first one done has 4 rows of holes with 20 , 24 , 36 , and 48 holes. Yes, I should have reversed the order of the holes to make more space between the 48, but it works just fine. I started a second plate and have rows of 21 and 28 holes done. I will be adding rows of 13 and 22 holes. these 8 rows of holes will give me almost all the common division senarios and more. I still have another plate that will hold 4 more rows of holes. I am figuring which number of holes gives the most additional division senerios and will put them on the last plate.

As soon as the brass for the handle and plunger arrives , I can make those and this project will be done and ready to use.

 

[MikeWi]

It's been said before, but I'll say it again. You really make this look easy!

 

[Mark_f]

It's been said before, but I'll say it again. You really make this look easy!

Actually, it is pretty easy, once I got going.

 

[machinistmarty]

Amazing work Mark, Kudos!

 

[wrmiller]

That newly sharpened .125 drill bit was done on that fancy sharpener of yours, right?

Nice work as always Mark.