39 Tooth Gear for my Emco Maximat V10 Metal Lathe

Project:
Make a 39 tooth gear for my lathe to allow me to cut 1mm metric threads on my imperial lathe

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

Process:
After I built the Dividing Head and the Fly Cutter making the gear was actually one of the more exciting projects.

The way my lathe is set up is in the gear change box there is a 45 tooth gear made out of nylon that serves as a sort of "sacrificial" gear in case the carriage got stuck or jammed into the chuck or any other such catastrophic event so that way it would strip the teeth off of the nylon gear instead of breaking somewhere else. The nylon gear has a metal core with the main hole for the shaft plus two smaller holes for two roll pins that lock together with a larger metal gear behind it.

It also looks like there originally was a second nylon gear which must have broken over the last 43 years of use, but the metal core was still there so what I decided to do for this gear is to bore the center hole to about 10 thou smaller than the diameter of that extra steel core and press it in with my vise. That actually worked out quite well and I can now officially cut 1mm threads on my imperial lathe.

The theory behind it is that I can use different gears in place of the 45 tooth gear to create an approximation of a metric thread. On my lathe, I have the following imperial TPI (Threads Per Inch) settings: 8, 9, 9.5, 10, 11, 12, 13, 14, 16, 18, 19, 20, 22, 24, 26, 28, 32, 36, 38, 40, 44, 48, 52 and 56.

Now, taking the 22 TPI setting as an example and converting it to metric, with the regular 45 tooth gear it will cut a (25.4 / 22) = 1.154545...mm thread.

HOWEVER, if I use a 39 tooth gear INSTEAD of the 45 tooth gear it will change to a (25.4 / 22) * (39 / 45) = 1.000606060...mm thread. As you can see, the error in my thread is 6 ten-thousandths of a mm for each thread. In other words, for a 4 foot threaded rod using my 39 tooth gear I will be off by less than one mm which for my applications is more than accurate enough.

I have also calculated a chart for most other metric threads and might cut me some gears just to have them on hand should I ever require other metric threads.

Math is awesome!!!

Pictures:

The dividing head set up with my gear blank

Cutting the first few teeth

Another view

The metric test thread

The 39 tooth gear installed at the place where the 45 tooth gear normally sits

Another view

A picture of the chart I printed out with the TPI settings, gear tooth numbers and tolerances

The finished 39 tooth gear

Another view

Documents:
Metric threads by changing 45 tooth gear.pdf

Tools:
Lathe and accessories
Dividing Head
Vise
Fly cutter

Materials:
2" of 2" nylon

Cost:
$0.00

Time:
2hrs

Savings:
$30

Conclusion:
It works! So pumped about this!

Fly Cutter

Project:
Creating a fly cutter to cut a 39 tooth gear

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

Process:
This one was actually quite easy. So easy in fact that I hardly took any pictures. I simply took a piece of 1-1/4" cold rolled steel, turned the shank down to 3/8", milled a slot at the bottom for the high speed steel tool bit, drilled and tapped two holes for the set screws and that was pretty much it.

Pictures:

Tapping the holes for the set screws

Close-up of the tapping action

The fly cutter in action on a piece of nylon

The finished 39 tooth gear

Tools:
Lathe & accessories
Tap & die set

Materials:
3" of 1-1/4" cold rolled steel
2 set screws

Cost:
$0.00

Time:
2hrs

Savings:
$30

Conclusion:
It works great

Threading Insert Tool Holder

Project:
Building a threading insert tool holder / boring bar to allow me to cut internal 1mm metric thread for the Ejector Nut for my Emco Maximat V10 Mill

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

Process:
The process in itself was fairly easy, but because I had never built one of these it took a little fiddling around. Also, I learned that a sharp end mill makes all the difference in cutting O1 tool steel. Duh...

I was getting ready to build the ejector nut for removing the end mill holder of my mill, but had not yet had a need for a small (under 5/8" diameter) internal thread so the first thing I had to do is build a tool holder for one of my threading carbide inserts I had scored on kijij a few months back.

I took some 1/2" O1 tool steel that I had bought at Metals R Us in Dartmouth, NS a while back, cut off a 5" piece and milled a triangle out at the end to hold my insert. After matching up the tilt-angle of the insert with another boring bar, I milled off about 60 thou at the top and about 80 thou at the bottom, then drilled and tapped a hole for the screw that holds down the insert.

After it was all milled to size, I hardened it by heating it with my oxy/acetylene torch to a bright cherry red and quenching it in motor oil. After it had cooled down I sanded the surface to reveal the shiny metal and tempered it to a slight straw color.

After letting it cool down slowly I was ready to re-install the threading insert and cut the internal thread for the ejector nut.

Pictures:

Using some Dykem layout fluid to mark the line to mill

Milling the top flat

Marking the height of the threading insert

The milled, drilled, tapped and installed threading insert

A side view

Top view

Dialing in the shank to mill

The finished threading insert tool holder

Threading the internal 1mm metric thread

The finished ejector nut

Tools:
Lathe and accessories
Angle grinder
Oxy/Acetylene torch
Tap & die set
Metal scribe

Materials:
Dykem layout fluid
6" of 1/2" O1 tool steel
Internal threading insert
Old motor oil

Cost:
$10.00

Time:
3hrs

Savings:
Probably at least $100 bucks if not more

Conclusion:
It worked pretty good. I ended up having to grind off some off the side of the bar but after that it worked great.

Ejector Nut for Emco Maximat V10 Mill

Project:
Building an ejector nut to remove the tool jammed in the mill spindle

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

Process:
In order to cut the worm and worm gear for my Meatal Band Saw repair I had to be able to remove the tool that was jammed in the spindle for my mill and in order to do that, I had to follow another fairly lenghty rabbit trail as follows:

1. I wanted to remove the tool from the mill spindle
2. To do #1, I needed an ejector nut
3. To do #2, I needed to be able to cut an internal 1mm metric thread
4. To do #3, I needed a 39-tooth conversion gear
5. To do #4, I needed to have a fly cutter, a threading insert tool holder as well as a dividing head

After I built the Dividing Head, the 39-tooth conversion gear and the Threading Insert Tool Holder I was able to cut the 1mm internal thread with my Fly Cutter into the ejector nut and use the dividing head again to cut a 13mm hex nut at the other end.

This project was actually quite fun. Once I had all the tools I needed, all I had to do is turn down a piece of mild steel, drill, bore and thread one side and use the dividing head to cut a hex nut on the other end.

Once the ejector nut and the ejector pin were built it was simply a matter of taking a wrench on the ejector nut and an adjustable wrench on the mill holder side and tighten them up to eject the morse taper #2 (MT2) tool which was locked in the mill spindle.

Pictures:

The top of the mill spindle

Hand drawn diagram of ejector nut

AutoCAD diagram of ejector nut

Drilling and boring the ejector nut

Cutting the internal 1mm metric thread with the newly built threading insert tool holder

After the outside was knurled and the hex nut side was turned to size

Using the dividing head to cut the hex nut

Close-up of mill before the first cut

Getting ready to cut the second (of six) sides of the hex nut

Getting ready to cut the third side

The finished ejector nut

Another view

The ejector nut installed on top of the mill spindle

Another view

The removed end mill holder

Tools:
Lathe and accessories
Dividing head
Angle grinder
Threading insert tool holder

Materials:
2" of 1.25" cold rolled steel

Cost:
$0.00

Time:
2hrs

Savings:
Probably at least $50 bucks

Conclusion:
I have now finally and successfully removed the MT2 end mill holder from the mill spindle

Diamond Dresser Tool Holder for my Emco Maximat V10 Metal Lathe

Project:
Finding a way to hold a diamond dressing tool to dress the grinding wheels on my Tool Post Grinder

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

Process:
After I built my Tool Post Grinder Holder to true up my 3-jaw chuck I needed a way to dress the grinding stone so I ordered some Diamond Dressing Tools on ebay and got started thinking about how to hold the tool in a way that is completely adjustable in all 3 axes.

After some thinking and researching I decided to create a base out of metal that clamps to the bed ways with a vertical threaded rod (adjustable in the z-axis), then have a horizontal piece of threaded rod which allows the tool to be adjusted in the x and y-axis and a last bushing that would allow turning the tool holder in different angles.

The horizontal piced had to be long enough to reach over the carriage of the lathe and it had to be sturdy enough not to bend when the diamond tip made contact with the grinding stone.

After the bushings were turned down and milled on one side, I brazed them to the threaded rod with some bronze brazing rods. I did this three times and drilled/tapped the final bushing to accept a bolt to tie down the diamond dresser.

In retrospect, I probably could have simplified things a bit and lose some of the adjustability, but since it won't be used all that often it will do just fine.

Also, although I used 5/8" threaded rod, the tool holder is still a bit more flexible than I would have liked it to be.

Pictures:

Drilling the support brackets

The finished diamond dressing tool holder

Another view

Close-up

Tools:
Measuring tape
Marker
Drill press

Materials:
12" of 5/8" threaded rod
2" of 1-1/2" cold rolled steel
3" by 4" by 1/4" mild steel plate
Two 5/8" nuts cut in half
Brazing rod
1 set screw

Cost:
$10.00

Time:
3hrs

Savings:
$50

Conclusion:
I would probably give it a 6 out of 10 because there's a bit more flex in the threaded rod than what I would have liked it to be.

Clamping Set for my Emco Maximat V10 Metal Lathe

Project:
Building a tie-down/clamping set for my metal lathe/mill

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

Process:
When I was working on the Dividing Head, I came to a point where I had to clamp a piece down to the mill table which was too large for my vise so I decided that instead of buying a Step Block and Clamp Set for about $75 bucks (CAD) at Harbor Freight (I might still buy one at some later time) I would make a quick set in my shop.

The bolts were made out of 1045 and hardened/tempered with my oxy/acetylene torch. The clamps were made out of some scrap 3/8" mild steel I had in my Scrap Metal Bin. One hole was drilled for the clamp-down bolt and the other hole was tapped for the counter-bolt which replaced the regular step blocks.

One thing I learned is that it's important to start the die exactly perpendicular to the bolt blank because I ended up cutting the tread quite crooked. It still works, but it doesn't look too pretty. If I had to make them again I think I would cut the thread on the lathe and then clean it up with the die just to get it to the perfect dimensions. That would eliminate the die pulling sideways and cutting a crooked thread.

Pictures:

Cutting the bolt blank

The threaded end turned to size

Using a die to cut the thread of the bolt

You can see how it cut a bit crooked at the bottom right

Doing the second tie-down bolt

After the heads were cut to fit into the T-slot of the carriage

Clamping down one of the parts for my dividing head once the bolts were hardened and tempered

Close-up

Another view

And yet another view

Drilling the holes with an end mill

Tools:
Metal lathe & accessories
Oxy/Acetylene torch
Tap & die set
Drill press
Angle grinder
Measuring tape
Marker

Materials:
A 2" by 4" piece of 3/8" mild steel
Two 3" pieces of 3/4" 1045 steel
Two self-locking nuts
Two 2" bolts in place of the step blocks

Cost:
$0.00

Time:
3hrs

Savings:
$75.00

Conclusion:
It works great