A "Wallaby" of my own

[steamer]

Thanks John,

I appreciate the input and the kind comments! I have an alternate motive also....my son.

I want to spend a bit of quality time with him making something together and to teach him how it's done....at least old school. with an engine....not just lego's

Having different perspectives from you guys gives him new vistas to think about...and a chance for me to transfer some hard won experience that you can't buy. Where would a nine year old go to find this knowledge in this day and age?

Dave

 

[steamer]

Hi! Dave did we miss a birthday. Did you say another year older and how old is that if you don't mind me asking?
I am still following you here and since I am new to machining I really haven't had any input for you as of yet. I will try to focus on giving my view and see if I am on the right track. I will want you to comment on my input when I do. I will continue to follow along here in the shadows.

Don

Yes Don, I had a birthday recently.....I'm almost and old fart now.... :big:,,,,I ain't dead yet!
And Don if you feel like contributing...feel free... :bow:

 

[ProdEng]

Well here is my opinion on a machining sequence for the cover. My instinct would be to machine the gasket face first and everything else that could be managed in the same setup. My thinking would be to replicate a fixture; grip the casting by the spigot and support the rest of the casting with a couple of screw jacks. Machine the gasket face, the spot face for the through bore and the mounting holes. When you turn it over you have a good reference face and some reference holes to set up on. Bore the boss inside and out followed by a quick face mill. Easy ;D

Jan

 

[Ken I]

A belated happy birthday Dave.

I would do it this way.

Linish the gasket face - place it face down on a surface plate / acetate film - place a box around it (possibly a modeling clay wall) -place a modeling clay extension on the boss - plus a couple of modeling clay plugs (for bolt holes) spray release agent - fill with polyurethane/ aluminium powder mixture (cures in about 10 mins).

Remove modeling clay - bolt to mill - skim the poly flat - turnover and clamp to table - you now have a perfect conformal support with bolt holes in it - the job normally "sticks" well enough for light machining - or simply add clamps as you go - machine the gasket face and all the holes.

A sharp smack to the boss (via the hole left by the modeling clay) should release the part - beware of reentrant angles - unlikely on a casting.

This may sound like a lot of work but it isn't and goes very quickly and is ideal if you are processing multiple parts.

I use all the materials commercially so they are always to hand - so for me its no big deal.

As one of our members bylines states - "when the only tool you have is a hammer, all problems look like nails" or something to that effect.

Just my 2c - since you asked. Next time I do it I'll post on it.

Regards,
Ken

 

[steamer]

Made up the oil pump housing today. It didn't go exactly as planned but I perservered.
I need to order the 10T pinion stock before I bore the center. I also need to make some toolmakers buttons to complete that operation. Then the front and back plates. Pictures later today.

Dave

 

[stevehuckss396]

Made up the oil pump housing today.

You forgot to post the pictures.

 

[steamer]

OK, I foraged around my scrap bin and found a piece of bronze big enough to make the oil pump housing. The problem is the size of the stock is 2.5" OD by 1/2" long.....tough to hold!

So I made a glue chuck.

First I bored the .875" back on the bronze and faced the stock in the 3 jaw.

Then I turned up the glue chuck from a piece of 12L14 I had in the bin. I turned 1 end to .375 and then faced the other end and turned a male .875" spigot. I turned it a snug fit in the back of my bronze disk.

Now the glue! I bonded the close fitting bronze disk to the glue chuck with superglue.

Now I mounted the glue chuck and part into a collet and turned the OD. The glue chuck is 1.4" OD and I was taking .100" on diameter with ease.
The fianl size was 1.1875"

I intended to machine the spigots like Pete did, but I blew the set up on the mill, so I turned the diameter down and brazed some bosses on and then dressed it with the mill. The glue chuck is nice as I can put it in the lathe or the mill directly and have at it!

I need to make up some toolmakers buttons to locate the bores for the gears.....I will be using a angle plate much like the one Ramon used to turn his crankpins on his current build.
http://www.homemodelenginemachinist.com/index.php?topic=18523.90

Dave

 

[steamer]

Oh I forgot to mention.

A superglue chuck will come apart if you heat the part to about 400F with a torch. The residue comes off with some acetone and maybe some light scraping with a razor blade and you can then do it again.

I obviously removed the part from the chuck to braze the spigots on. I then pickled the part and cleaned it and remounted it to the chuck and cleaned it up on the mill and then wire brushed it in the lathe.

It needs ( 8 ) 2-56 clearance holes and the gear bores done still. The holes will be done in the mill, while I think I'm going to bore the gear locations on the lathe.

Dave

 

[stevehuckss396]

OK, I foraged around my scrap bin

Better, Thank you!!!


That collet chuck is sweeeeeet!!

 

[steamer]

That's my old Bison Chuck that I bought way back when I had my Atlas...Bison had just come out with it and the price was still reasonable. It also has an index ring on it with a dedicated index latch system.
It can be set to a specific position for ZERO rotationally. It has 24 positions.

I have modified the backing plate to make it adjust true also.

Dave

 

[bezalel2000]

Hi Dave

scratch.gif

What's the unfinished ply wood tennis racket for, between the chuck and headstock?

Bez

 

[steamer]

Hi Dave

scratch.gif

What's the unfinished ply wood tennis racket for, between the chuck and headstock?

Bez

So WHEN you drop the chuck..( you will drop the chuck) it drops on the plywood and not the ways which will leave a ding of shame!
;D

Dave

 

[mu38&Bg#]

I think he's asking about the aluminum plate that is part of your indexing arrangement.

Greg

 

[steamer]

That's actually steel! It's part of the indexing attachment. It's the mount for the index pin assembly. It mountes on the OD of the front bearing housing with a circular clamp. I roughed it out and never finished the edges as I wanted to see how it worked first...it worked great!....but I never took it off to clean it up! :big:

Guess I gotta now....

Dave

 

[steamer]

Ordered the pump gears today....I think I'm going to take a page from GailNM playbook make some cutters, and cut some gears for the rest of it. My son wants to cut gears!

Dave

 

[stevehuckss396]

Ordered the pump gears today....I think I'm going to take a page from GailNM playbook make some cutters, and cut some gears for the rest of it. My son wants to cut gears!

Dave

I have always wanted to learn to cut gears. Post some pix of your setup's if you think about it.

 

[steamer]

Will do Steve! I've cut gears before, and it's mostly tedious....not real technical
I'm going to make the cutters for this via Ivan Law's book and GailsNM spreadsheet for cutter dimensions.

You'll notice that the gear listed isn't 40 but 35. A 40 tooth gear falls within the range of the cutter dimensions show, however, the cutter is a standard endmill size. Which makes life easier.

Due time....and I get to use my Aciera in anger....can't wait!

Dave

 

[steamer]

I'm going to use Wheeltapers basic setup to make the cutters.

http://www.homemodelenginemachinist.com/index.php?topic=10449.0

Dave

 

[tel]

I have always wanted to learn to cut gears. Post some pix of your setup's if you think about it.

I've done a little photo essay here.

 

[stevehuckss396]

Then what, swing it around like a flycutter only level?