$20 power slotter for my lathe!

[John Hill]

  $20  slotter and maybe gear cutter!

Hmmm... 20  NZ bux must be about 7 quid!

This little chinese drill press was too cheap to ignore at about $20 and it has been resting it its box while I decided what it might be useful for.

First step, mount it on the cross slide of my 12x36 lathe.





The orginal base has been replaced by a turned plate and a support fashioned to hold a ball bearing in line with the spindle of the drill.




A spindle is mounted in the chuck with the other end in the bearing. A simple cross drilling and a set screw form a simple tool holder for 6mm tool steel.  As you can see it cuts a nice slot in the end of this piece.



The next step is to make an indexer for the lathe spindle and fortunately I have a set of Hercus lathe change gears on hand that can be pressed into service.  The change gears are not Chinese but they do appear to be of adequate quality.

[Dean W]

That's an interesting setup, John.   It looks like it has a number of possibilities.  Along with maybe gear cutting, long keyways should be workable too.

"The change gears are not Chinese but they do appear to be of adequate quality."

Now, that's funny!  Save your money, and one day, you too can have a set of plastic lathe gears!

Dean

[John Hill]

{A couple of days later!}

I have made an indexer to go with the vertical spindle:-

I made a pile of bits...




...which put together look like this..



...the aluminium bit screws into the end of the spindle and the small hole goes over the stud that secures the gear case cover..


One detail which you cannot see is that I added a nut on the gear cover stud inside so that the knurled knob has something secure to screw down on to, not just the springy fibreglass cover.

Now I should be able to cut a few gears!

[Bernd]

Boy, talk about a simple solution. Nice design John. 

Bernd

[Stilldrillin]

Now, THAT`S clever! 

Very well done John..... 

David D

[Dean W]

Now, that's one slick direct indexer. 
You can get nylon or plastic gears pretty cheap, which should open up a
lot of different tooth counts/indexing spaces for your work.

Good thinking, John.  Looks neat, too.

Dean

[fluxcored]

Wow, this is fantastic!! I'm currently working towards cutting a 32T change gear and your setup solves a lot of issues for me.

Does your setup cope with cutting steel?? I'm assuming the work piece in the chuck is ali. Not a problem really because I plan my gear to be brass/bronze.

Dean, exactly the reason why I'm currently scavenging old printers for plastic gears.

[John Hill]

Hi Fluxcored.

It does cut steel but it is really hard to keep the carriage feed slow and steady enough as (at least with my lathe) it is not possible to use power feed without the spindle turning.

John

[andyf]

That looks a great idea, John. I've got a spare Chinese drill press which I'm eyeing up.....
A couple of questions:
Do you think there would be any virtue in shortening the column (and the bar which holds the cutter) to improve rigidity? Not so much that you can't see the cutter, of course.
The clearance between my quill and the head casting is, to put it politely, generous. Your idea doesn't require the quill to move up and down as when drilling, so I assume you have fixed it to the head casting - was this with a slit and a pinch bolt, epoxy, or some other cunning ploy?

Andy

[John Hill]

Andy
I left the column full height so that the majority of the forces are on the lower bearing.

No, I didnt modify the drill head in any way.

The real issue with rigidity, as far as I can see, is the lower bracket which is a simple adaptation of the original drill table clamp. The bracket is much longer than it needs to be and would be better if it was shorter, the clearance required to the column is only the radius of the cutters to be used.  However I made it that long to line up with the drill spindle.

What would be better would be to make two rigid brackets (shorter of course) and use two spur gears to drive it with the drill. That would improve rigidity and reverse the rotation of the cutter shaft which would make feeding easier.

As it stands, the thing I would like to improve most is the convenience of feeding at a slow and steady rate.

BTW, I have since trimmed the corners off that bit of ugly angle iron on the lower bracket!

[75Plus]

Hi Fluxcored.

It does cut steel but it is really hard to keep the carriage feed slow and steady enough as (at least with my lathe) it is not possible to use power feed without the spindle turning.

John

John,

This comment set me to thinking. I also have a 12 X 36 lathe similar to yours. It would be possible to replace the drive shaft for the carriage with a longer one and add separate power feed on the right end of the lathe. From the looks of mine a length of keyed shafting of the proper diameter extending through the bearing block would be fairly easy to do. An alternative  would be to shorten the existing shaft and add an extension similar to this sketch.


Joe

[John Hill]

That should work Joe.  I was thinking of drilling and taping the end of the shaft so I could screw some sort of drive in.

[madjackghengis]

John, I've gotten a couple of windshield wiper motors from a surplus center listed on the internet as just that, for few bucks, and any one of them would make a good power feed.  I've also used a 9/16ths socket on my drill/driver to put power feed on the top slide, you could drill and tap the lead screw for a bolt and use that method, and there is no shortage of old drill/drivers which could become permanent fixtures on machines for power variable feed.  Don't forget for indexing, one can always use a strip of card stock, around a round piece of plywood, center drilled, and mounted on a drill press table, having used the dropping vertical parallels to put lines on the card stock and drilling holes in a piece of stock attached to the plywood, to index odd numbers and primes.  It looks like you should be cutting gears for a while good job on the milling column for your lathe. mad jack

[John Hill]

Mad Jack,  the wiper motor is a good idea and just so happen to have a few of those!  (Off topic, one less than I had as someone I know was lamenting the problems he was having fitting wipers to his Lancia Stratos and what he really needed was a complete set from an Austin Maxi (c1970), he was surely beamed with joy when I pulled a complete set out from under my bench!)

Back on topic, I am thinking of fitting the drive to a change gear that I can put in place when I need it, that would drive via the lower gear box and prevent this old duffer starting the lathe with the auxilary drive in place!