# One Rob and hacksaw blade later



## Norppu (Jul 13, 2018)

A lot of my (future) projects will be needing gears. Making gears with milling machine and indexing head would of course be quite easy. Since I do not have a milling machine not to taslk about an indexing device I need to look for another solution. Buying a milling machine would probably be the best but that thing needs a place to sit on. At the moment I am a little bit out of space in my shop so that is not an option. Also, the negotiations with my financial advisor would be quite something.

I ended up in creating a device that can be used to mill gears in a lathe. I got the idea from looking a video made by Rob aka Xyundu. This was one of the reasons I bought the vertical slide. Rob's design is looking really temporary but it served as a source of the idea. So I decided to make mine a little bit more like a tool.

Starting with a mild steel block 100 x 100 x 20 mm.



After doing the basic layout and boring some of the needed holes while the block was still intact I started the process of making a gap in the middle of the block. I do not own a bandsaw so my options are either a jigsaw or a hacksaw. Ended up using both. The jigsaw was used to make room for the hacksaw blade on the last cut. I have done a lot of cutting with hacksaw and I have learned diverse methods to get the cut straight. Without proper setup the saw tends to wander everywhere and occasionally also in the desired direction.






After a decent workout I now have a gap in the block. The surface finish is horrible. Well, I've got a bunch of good quality files. I also enjoy filing as there is something pleasant in getting really smooth finish on a lump of steel. It is like having a portable milling machine. I am quite satisfied with the result. It took me 3 hours to finish and I enjoyed every minute of it.



Rob used a cardboard wheel in order to index the gear. I will use a more permanent method. As I am an IT-Dinosaur I have collected some IT-Junk during all these years. I have a few aluminum alloy disks which are perfectly round, 3 mm thick and about 150mm in diameter. I will convert these into indexing disks and have a proper setup in the gear grider. Indexing the indexing disks involves some CAD work.


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## Rooster (Jul 13, 2018)

Greeting's Norppu, i also use a hacksaw and files in place of a milling machine. There is alot of satisfaction in making what you need by hand, but i do wish i had a nice old vertical mill. Atlas made a nice gear cutting attachment for there lathes that i have been thinking of making.
I look forward to seeing more of your project, keep us posted.


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## ttabbal (Jul 13, 2018)

Are those HDD platters? I have a stack of old drives I've been meaning to tear down...


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## brino (Jul 13, 2018)

@Norppu 

Watching this thread.....already looking forward to the next episode.
Thanks,
-brino


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## Boswell (Jul 13, 2018)

I did a fair amount of fabricating with only hands tools but I am SOOO glad I finally got some powered shop tools. I never got the "romantic" aspects of using hand tools. But that is just me. Very nice work, and I am also looking forward to seeing your progress.


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## Norppu (Jul 13, 2018)

Actually I am not a romantic man. I just like to relax by doing something really demanding that takes my thoughts away from my job. Now as I am in vacation I really intent to take a deep dive on manual work. Rather than having DRO I use the ARO and even ERO (Eyeball ...) whenever sufficient.
For me it is really important that I separate my actual job (Datawarehousing specialist) from my hobby.

Those aluminum disks are guts of several bigger hard disks. They are perfectly round and made of some quite hard aluminum alloy. In addition these have some fancy plating which contains the magnetic material. It is like glass and does not wear easily. These are perfect for indexing disks.

I like the 4-jaw chuck. In addition to be able to align and realign the work piece perfectly it also allows use of scrap material. The block that I removed from the frame is now on it's way to become the indexing disk mount. The thread is M40 x 1. I will bore the hole to be a interference fit with a 10mm axle.  First drill to 9.5 mm and then bore to 9.98 mm. I like to push my limits.

The swarf tray was a modification which I made quite early. Ity is made of 3mm polycarbonate and protects the ways from swarf and other falling objects like chucks, work pieces etc... It seems that there is more gravity in my workshop as things tend to fall ...

When I threaded the thing I noticed that it actually grow on diameter as the disks did not fit any more. Delicate touch with fine file and metal brush fixed that. Obviously some burr.


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## Boswell (Jul 13, 2018)

I really like your swarf tray. How is it attached? Do you every need to remove it when working close to the chuck?


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## Norppu (Jul 13, 2018)

Boswell said:


> I really like your swarf tray. How is it attached? Do you every need to remove it when working close to the chuck?


You nailed it. The first version stumbled with the headstock gearbox. Then I bent is as shown (the original was straight) and now it slides up the headstock wall and there is no limitation on cross slide movement.
Bending polycarbonate can be done either by just bending it (it does not break) or first applying heat to the area to be bent and then bending it (bends easier).  Polycarbonate does not melt, it just becomes softer and then it burns.


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## Norppu (Jul 14, 2018)

Interference fitting a 10 millimeter axle into a supposedly suitably sized hole ... FAIL.
There are quite some difficulties with small dimension interference fitting:
- it is quite hard to measure a 9.9x millimeter hole accurately. I have snap cages and the smallest was barely small enough to fit in there. When measuring I got quite some random results.
- the thermal expansion of that small hole is neglible. That translates into very precise tolerances.

What happened was that the axle went in 10mm and then stopped there. Could not hammer it more in nor could I get it out enymore.  So far so good - it sits tightly where it is supposed to be sitting.

However, the plate holder was no more concentric with the axle. Wobbly is a mild expression. Ahh ... Ok, will need to reshape the holder, there is enough material for that. Now it is concentric but the threads are not. So I had the thread it again. This time I chose another thread type - I do not know the name of this but it is square on other side the other side having a 15 degree angle. I have inserts for this thread type and also holder and a boring bar for those.

What I did not realize was that when threading it is absolutely disastrous if the workpiece slips in the chuck. Mine did and the the insert broke. Luckily the workpiece did not suffer (much). Replaced the insert, spent some quality time figuring out how to realign the thread and now I have a good enough threaded plate holder with axle. Next piece is the nut - it will be interesting to make.


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## Norppu (Jul 18, 2018)

After making the threading tool for lathe I was able to machine the threads (this was the third time in  row) for the plate holder and inside the nut that is used to hold the plate in place.



Again, some DDR mystery tool steel for making the index lock. It is of a simple construction with two hardened pins glued to the holder. There is a spring that pulls the braced steel pin against the disk edge. If there is a slot in the edge then the steel pin will fall into that edge and locks the disk.

The lock pin is 4 mm in diameter which happens to be the same diameter as chainsaw sharpening files. What is still needed is a pin that indexes the disk with the disk holder. It will also be a 4mm hardened steel pin.

Milling toll steel with a milling attachment is scary and it produces swarf that is razor sharp and is painful in hands.


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## Norppu (Jul 18, 2018)

Basically this tool is now ready. Maybe two handles for tightening the work piece squeezer. Also, a fly cutter to accommodate gear cutting bits.

Here are the individual components.

The frame which I made from 20mm thick hot rolled steel plate. It has two 4mm pins for aligning the index locker.



Index disc holder with thread which I made three times over. I also learned that interference fitting small diameter components is not a trip in the park. It has a 4mm pin to register the index disc.




Nut for keeping the index disc in the holder. I made a threading tool because I had no internal threading tooling. The threading/boring bar works really well.



The index locker is made of tool steel. It has a silver soldered 4mm pin to lock the index disc. The groove is 4mm wide to slide with the fram pins. The pins and the locker are hardened.



The work piece is held by this expanding holder. The index disk holder shaft has a flat to accept the set screw of the work piece holder. This registers the index disc with the work piece. When the set screw is tightened the holder expands and grips on a center hole of the gear blank. In this case the hole needs to be 13mm but it is easy to make other sizes. The holder it self is split and the I measured a 0.3mm expansion with very light tightening.



The work piece is pushed against the bottom of the frame while machining the gear teeth. This nut is used to tighten the assembly. This is still missing a handle to operate the tool without extra wrenches. The thread is M16 x 1.



This is how the tool looks when it is is assembled.


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