2 speed transmision evolution----

[12p3phPMDC]

Right on, thanks for the pics Miles...that's pretty much what I had in mind.
That integrated tilt feature is pretty cool.

Thanks for the explanation Thud !!

Great stuff!

 

[12p3phPMDC]

Miles,

Is that a MT #? mandrel in the center of the rotary table?

What are those threads for?

When I'm shopping for a rotary table, I keep thinking, "I need a 3 jaw chuck to go with it."

But, seeing the mandrel sticking out of the center of the rotary table got me thinking about the morse taper
in the center and that allows you to do some operations with out a three jaw if you can somehow
bolt your part to the mandrel. It looks like you have a "draw" bolt/bar in the bottom keeping the mandrel seated?


THud,

Your explanation of the bit breakage makes total sense...I think....
Does is it only happen in one direction, i.e. when you are leaving the slot in the direction the cutter is spinning?
and when you make the return path on the other side it's butter..?

 

[Thud]

Whew!, I finaly finished all the rough machining op's tonight on the dog sprockets. Still need the final de-buring & a little love when final fitting, but I feel like real progress has been made the last 3 days.

The sprockets are now about 1/3rd of their original weight. final thickness of .375" & just enough meat to still be a sprocket.
Here it is engaged with the clutch hub.

12p, the bit breakage is far more likely when entering a pocket. It automaticly becomes a climb cut in that senario. again only an issue when dealing with interupted cuts.

Unless I am mistaken, I recognize Miles's adapter on his rotary table as a 1x16 or 1.125"x16 (??) old standard chuck thread. I assume it has a MT in it as that is pretty common. On my 4" cheapo I made a indexing plate that falls on center & bolts to the turn table. It has a removable .75" mandrel that can be modded to fit the need.

 

[j3tch1u]

Before they are done, each driven sprocket will have been operated on with 4-set ups, & no less than 50 passes of the varius tools to make the cuts to depth. All hand cranked on an old smithy 3 in one mill.

very nice. i can imagine it took a lot of time to setup and recenter not to mention tool changes. are you using a wiggler? i've recently started using an led edge finder--love it.

 

[12p3phPMDC]

Awesome 8)

It seems to be a simpler part to machine because you probably don't need the small bit...


In general it appears that all the cuts for the beginning
and ending of the dogs and slots are radial lines.

So, it seems to cut the dogs
you'd
- first counter bore the end
- set the angle on the rotary
- Set the edge of the bit to be on the center of the rotary axis (makes it easy to get radial lines)
- make the cuts by feeding the Y axis in and out
- rinse and repeat....then clean out the waste?

 

[Miles]

Miles,

Is that a MT #? mandrel in the center of the rotary table?

What are those threads for?

12p,

It's an adaptor with the standard screw chuck mount for Myford lathes (1-1/8 x 12 tpi Whitworth thread).

It's not a Morse tapered hole in the table, it's a parallel hole. I adapted the adaptor to fit and tapped a hole in the end so that it could pulled down onto the table with studding and a nut.

Most rotary tables have a Morse taper hole in the centre and you can buy a Myford (or other) chuck adapter to fit this.

 

[etard]

Ok, back on topic.

Thud,
I can't wait to see how this thing speedshifts, it will send massive shock loads through the drive system. Are you putting any sort of dampening into the gearbox? I want one!! This truly is a labor of love for all those here on ES, cuz you will never make enough money back to offset all the labor you have put in. I, for one, am appreciative of this even though I might never benefit from this gearbox directly, perhaps it will prove there is a market for such an item and some company will pick up the baton. I'm wondering what those threads are cross sectioned, are they from holding it in the machine, or will this be how the sprocket is mounted to the shaft? Keep up the good work my man.

 

[Thud]

Etard-
Those threads are the remnents of the original set screw. Totaly out of play on the re-pourpose.
Dampening schnapaming! I am designing a cush drive rear sprocket carrier, to smoothe out the shock loads
this thing should do full power shifts!

I am still torn between making my next build another out law bicycle, or just bite the bullet & re-use an old motorcycle title & call it what it is. (prolly "out law" as that is my nature )

 

[AussieJester]

I am still torn between making my next build another out law bicycle,

:: VOTES for outlaw bicycle:: High end downhill mountain bike rc motor and 2 speed tranny :: druuuuuels::

[youtube]JoqDYcCDOTg[/youtube]

 

[Thud]

I did a quick model for a customer....I thought I would share this for ease of visualiation:

motor mount machined to accept an Astroflight or an 80mm Turnigy. The flange on the bottom is the mounting area to the frame of the vehicle. the nub sticking out is the actuator shaft.
perfectly clear??

looking for good ideas on mounting options......I will be welding tangs to the frame for bolt on security. Clamps could be fasioned easily enough for a seat post mounting senario(assuming there is room in that area) feed back from hillbilly would be good, He was looking for an easy packadge in another thread. no bad suggestions....

 

[johnrobholmes]

That looks like a great way to start the mounting. Maybe a third point for rigidity? I won't be the best help here though, as the frame will be built around the box instead of vice-versa

 

[enoob]

no bad suggestions....

light sabre holder is missing as is the bolt pattern for an enoob/alternator. :lol:

just ribbing ya thud. very nice work .

ive been talking to the old man and we may just find out how much fun some bass fishing could be . he imports trucks from down south and i may just do a trip out east come spring . see what kind of trouble we could get into.

 

[Thud]

Hi Ho,
Enoob, you can stop by anytime bro. Make a list & we'll build someting cool 8) Got a ton of bass holes also in every direction. My treat.

Spent the day making tooling to ease set ups for production. Had a good casting session thursday night,
Here is a pile o' trannys waiting to be machinerd.

peek a boo! this one has bearings.

I call this style case the "AJ Smoothie". The plan is to grind & polish it to a mirror finish & powdercoat it the reagle blue Aussi Jester is so fond of. (casting alloys hate anodising Kim) But powder over a chrome like shine is schweett lookin'. This ones kinda rough outa the sand.

 

[damcard]

That's impressive. I can't wait to see the final unit. -David

 

[AussieJester]

Freakin schweet Thud good too hear the casting went so will this time round for you
too. Blue powdercoating FTW

KiM

 

[flyinmonkie]

Thud,

Have you thought of getting the cases molded out of high density plastic? The initial tooling is expensive, but then it gets pretty cheap if you make others. Could lighten up the whole thing as well. It would be hard to make it shiny bling, but you could get about any colour.

Clay

 

[AussieJester]

Could lighten up the whole thing as well.

Clay

If I can get my hands on one of these masterpieces ill show you how to "lighten it up" quick smart

KiM

 

[12p3phPMDC]

Thud,

Lookin good man!!

Do you use a boring head to counterbore the bearing pockets?

 

[liveforphysics]

Thud,

Have you thought of getting the cases molded out of high density plastic? The initial tooling is expensive, but then it gets pretty cheap if you make others. Could lighten up the whole thing as well. It would be hard to make it shiny bling, but you could get about any colour.

Clay

Plastic is a tranny fail. Any flex means failure for trannys. Aluminum with ribs for stiffening is what it takes to make a tranny reliable, and what Thud made looks perfect to me.

The thing looks pretty damn light to me, and I bet to get close to equal stiffness from plastic it would take more weight, if it were even possible.

 

[Thud]

FM,
I would think a potential material would be the graphit re-enforced plastics simular to what's used on current hi-end rc car chassis might be alright for a chain system I have designed. (I am with LFP when it comes to stifness for a real gear 2 gear tranny though). I really doubt there will be a high enough demand to look at that option regarding trans cases. Given I can make the match plates for a production foundry to cast these by the hundreds, I hadn't considered plastics as an option. I am going to make a carbon fiber unit just for looks soon enough though. Thanks for the sugestion though.

12p,
You seem very interested in the machining procecess, A budding tool & die hobbyest? given I need to make accurate holes in qty. to fit these bearings, I made a series of mods & some new tools to do just that.

step 1) Is of course locating the first hole & clamping everything securly. Careful layout & wigglers work fine.
2) drill a pilot hole to depth. The pilot hole dia. is determined by of the chisle point of the next tool
3) drill the next rough dia hole to depth. I modified a 1"dia. drill bit for a very shallow point
4) bore the final dia with the boring tool. (this one is made to length to fit this set up & matches the
other tool lengths to ease tool changes without disrupting any positioning.
Here is a picture of the tools in sequence:

the block to the far right is a simple setting gage to allow tool sharpening & repositioning back to correct.
diameter.

here it is in use. the tool body is .75" cold rolled steel. a 3/16"sq. lathe tool cut & ground to fit,secured with 2 10-32 set screws.

 

[amberwolf]

12p,
You seem very interested in the machining procecess, A budding tool & die hobbyest?

Probably not the only one here--I know I am, but I don't even yet know enough to ask useful questions. Wait till I learn more and I'll have tons of questions for you!

 

[flyinmonkie]

Ah yes, I didn't think about the flex and the forces on the case. Metal it is then.

Kim, if you drill holes in it you'll have gear oil running all over the road. lol

Keep up the great work Thud.

Clay

 

[amberwolf]

Drill holes and fill them with lexan plugs.

 

[mud2005]

2) drill a pilot hole to depth. The pilot hole dia. is determined by of the chisle point of the next tool
3) drill the next rough dia hole to depth. I modified a 1"dia. drill bit for a very shallow point

wow, thats amazing! Is that done on a mill or drill press?

I needed to make a 1-1/8" hole today and I used a 3/8" drill bit then a bunch of end mills from 1/2" to 3/4" cutting 1/16" at a time until I got to the boring head.

how do you use a 1" drill bit?? I find the chatter is way too much. I'm using a mini mill though, are you on a much sturdier machine?

 

[Thud]

Mud,
I am using a mill. (old smithy 3-1 machine...very flexible flyer) medium slow rpm's. correct feed rates & the most important item:
properly tightend gibs on the machine. (this is a quite stiff set up)
A lot of newer machinests are not aware that you can adjust your machine to get the results you desire.

Another tip is properly sharpend tool.
The pilot hole should only be the dia of the chisle point.
opening a .75" hole with a 1"dia drill is begging for chatter & drift. not enough load on the cutting edge to stabilise the tool.