Dividing Head for Indexing and Cutting Gears

Project:
Building a dividing/indexing head for my lathe

Difficulty Level (Easy, Medium, Hard, Insane):
Hard

Process:
Similar to Alice tumbling down the rabbit hole, I've been on a journey on a thousand rabbit trails lately. It all started when I bought a Metal Band Saw, didn't notice that the previous owner kludged the gearbox together with some low-quality machine screws which came loose, jammed up the worm and snapped off 3 teeth of the worm gear. So here's the journey along these rabbit trails ending with the dividing head:

1. I need to replace the worm gear used in my metal band saw
2. To do #1, I need to be able to cut a worm with a 2.76 TPI pitch
3. To do #2, I need to have a 96 tooth gear for my metal lathe change gears
4. To do #3, I need to have a dividing head

I decided to not do a full write-up, but instead let the pictures speak for themselves. Please feel free to email me at eigenheerc at hot mail dot com if you have any questions.

A few more notes:

1. I had to make the chuck spindle and the chuck spindle guide plate twice because after I had finished it for the first time I realized that I didn't have enough room to lock the chuck spindle with enough force so I decided to make it pretty much the same size but out of square stock so I had some room for the locking clip in the corner

2. When you hear a tap creak TWICE, STOP and take it out. I learned that the hard way by snapping it right off at the very bottom of a hole. It was very nasty. I did fix it by welding it and re-turning it but in the end it didn't matter anyways because I had to re-do the entire part.

3. I also learned the hard way that it's a lot easier to move holes in AutoCAD than AFTER they are drilled

4. I can see how people would get addicted to making metal chips; the colors are truly beautiful

Videos:

Pictures:

Parting off a 4" diameter piece of metal for the base

The three parts making up the swivel base

The base assembled and marked for the holes

The underside of the swivel base

The finished swivel base ready for install on the gear reducer

The gear box I bought at an auction among other things for a few bucks

Matching up the center of the gear output shaft with the lathe center

Another view of the bear box on the swivel base attached to the cross slide of my lathe

Another view from further down

Testing the concept of an angled miter gear cutting scenario

After the gear box was taken apart, sand blasted and painted

Milling one of the cover plates perfectly parallel to the gear box

The finish after milling the cover

The cleaned up gear box

Getting ready to cut off a piece of the 4" diameter 10V45 I bought at an auction for $2 bucks

Facing the blank

Done facing and getting ready to turn it down to size

Starting to turn down the chuck spindle support part

Another view, with the colorful chips

Almost done turning down the chuck spindle part to the proper diameter

Colorful chips

Some more chips

The chuck spindle guide plate

Another view

Mounting on an arbor to get both sides of the part concentric

Another view with the diy lathe dog. I don't like it a lot so I'll probably make another (smaller) one

Marking out the holes on the chuck spindle

Getting ready to cut the 8 TPI thread

Cutting a relief groove for the thread

After the scratch pass

Back to the chuck spindle support plate

Clamping it down to the cross slide

Drilling the holes in the chuck spindle support bracket

The front of the chuck spindle support bracket

The back of the chuck spindle support bracket

The finished chuck spindle

The chuck spindle inside of the chuck spindle support bracket

After I broke that bloody tap. It was a 1/4" x 20 HSS tap and should not have snapped as I was being very careful not to put too much pressure on it. This was such a PITA

I was so mad so I took the oxy/acetylene torch and melted the crap out of that stupid tap

Fitting a piece of metal into the hole

The fitted plug

After the plug was welded into the chuck spindle support bracket

After the weld had cooled down

After the chuck spindle support bracket was machined back down to size

The outside actually turned out quite nicely

The two holes drilled and tapped. They ended up not being strong enough to clamp down the chuck spindle so I had to re-do this entire part

Close-up of the welded and machined area where the tap broke off

The chuck spindle support bracket mounted to the gear box

The finished (first version) of the chuck spindle and support bracket

Getting ready to cut another chunk of 4" diameter 10V45

Another chunk I bought at the auction for a few bucks. This one is a 12" by 16" by 1" mild steel

Cleaning up the surface

Marking out the piece for the (second version) chuck spindle support bracket

PERFECT

Milling the other side

Getting ready to drill and then bore the hole

After the front was faced off

Boring the front

The finished bore

Dialing in the back side

Test fitting the (second version) chuck spindle support bracket on the gear box

After the holes were drilled and counter sunk

Starting on the chuck spindle. This had to be perfectly accurate. I ended up turning it to 1 thou oversize and then sanded the rest down to within half a thousands

Starting on the threaded side of the chuck spindle

Almost ready to cut the thread

Bluing the part with Dykem layout fluid

The finished chuck spindle

The chuck spindle (second version) fit into the chuck spindle support bracket. There is less than half a thousands gap between the two parts. This is probably the most accurate part I have ever machined so far

Marking out the position for the chuck spindle locking clip

Milling down a piece of mild steel to make the chuck spindle locking clip

Laying out the two holes for the roll pins to prevent the clip from rotating when tightening it

The finished chuck spindle locking clip

Close-up of the locking clip

Another view

Getting ready for the crank handle extension

After the scratch pass

The threaded end

The crank handle extension installed with a small set screw

Some more beautiful metal chips

Getting ready to bore the indexing plate holder

The finished indexing plate holder

The back of the indexing plate holder

The front of the indexing plate holder

Test fitting the indexing plate holder

After the mounting holes were drilled and counter sunk

Before installing the screws

The indexing plate holder installed on the gear box along with a test crank handle

5/8" melamine pattern for the sector arms

The two sector arms and two of the three indexing plates

Facing off the indexing plate

The finished indexing plate

Another view

Boring out one of the sector arms

Almost finished one of the sector arms

Another view of the sector arm

Test fitting the sector arm

After my neighbor drilled the indexing plates for me on his CNC machine. Thanks Bernie! That saved me countless hours of mind-numbing drilling

Cutting some small grooves to make it easier to follow the correct hole pattern

Drilling the second sector arm

Both sector arms test-fitted on the dividing head

Using the dividing head and the mill to mill the outside of the sector arms

Close-up

Top view of milling the outside rim of the sector arm

Another view

Milling the slant of the sector arm

Another view

And another one

Close-up of milling the sector arm slant

And yet another view

Installing a  little ball bearing with a spring on the underside of the sector arm to provide a bit of friction to the sector arms

Close-up of the installed ball bearing

The finished crank handle my brother in law and I made on night

The bored out side where the plunger will go

Starting on the plunger

Test fitting the plunger in the crank handle

Close-up of the latch pin of the plunger in the indexing head plate against the sector arm

Knurling a brass knob

Tapping the brass knob to 5/16 x 18

The finished brass knob

Another close up of the latch pin

The modified plunger with the latch pin at the end

The finished plunger

Another close-up of the plunger

The finished brass knob to lock the plunger in the retracted position

Marking out the hole in the crank handle for the brass knob that locks the plunger in the retracted position

The finished dividing head

Close-up of the knob that locks the plunger in the retracted position

Close-up of the knurled brass knob

Close up of indexing plate 2

Indexing plate 3

Close-up of indexing plate 3

Indexing plate 1

Close-up of indexing plate 1

The chuck spindle locking clip

Another view of the locking clip

Another close-up of the latch pin in one of the holes

Another view of the brass knob that locks the plunger in the retracted position

Top-view of the latch pin engaged in the indexing plate against the sector arm

The latch pin engaged and touching the other sector arm

Close-up of the knurled brass knob

Close-up of the locking screws for the sector arms. The silver screw locks the sector arms together, the black screw keeps the sector arms from falling off

A front view of the crank handle, sector arms and the indexing plate

Another front-view

The finished dividing head

Side View A

Side View B

Index Plate Holder

Crank Handle

Index Plate Side View

Sector Arm 1

Sector Arm 2

Plunger

Crank Handle Extension

Chuck Spindle Guide Plate

Chuck Spindle

Chuck Lock Clip

Chuck Spindle Guide Plate Front View

Chuck Spindle Guide Plate Front View with Chuck Lock Clip

Index Plate 1

Index Plate 2

Index Plate 3

Tools:
Metal lathe & accessories
Angle grinder
Oxy/Acetylene torch
Hammer
Measuring tape
Drill press
Vise
Tap & die set
Bench top grinder
Aluminum foundry


Materials:
5lbs cast aluminum
12" of 4" diameter 10V45
6" of 2" diameter 1018
6" of 5/8" stainless steel
1" spring 3/8" diameter
1" of 1" brass
Nuts & bolts

Cost:
Probably about $50 bucks in materials

Time:
40 hrs

Savings:
$1000

Conclusion:
It works great. I can't wait to start cutting gears