TB2 - Elmer's Coomber #46

[Brass_Machine]

Team...

The next build will be the Elmer's #46. Since we have some relative new people, I want to keep this one simple... so to Elmer's scale it will be.

My current build team consists of:

1. Bob Warfield
2. JMe - Jacques
3. Bretk - Bret
4. Myself
5. te_gui - Brian
6. PowderKeg - Wes
7. Joe D - Joe
8. ksouers - Kevin
9. kustomkb - Kevin
10. GailInNM - Gail
11. zeusrekning - Tim
12. kvom - Kirk
13. Dick L. - Dick


We will be doing the parts assignments in the next couple of days. You can get the plans from this LINK.

Eric

 

[te_gui]

So is this where we start chiming in as to what parts we would like? I would volunteer for the bases, I have some aluminum tooling plate that is crying to be used. Also I see we are going to stick with the "stock" size, are there going to be any other mods made to the plans to perhaps improve performance, ie bushings, ball bearings, etc.

Brian

 

[Brass_Machine]

We will be building 16 engines. 1 for each team member (total 13). 1 for HMEM to display at shows. 1 to sell for charity and then 1 as a gift for our fearless leader (Rake60) as a thank you for the board.

Parts break down:

Base (16 Each) - te_gui
Bearing Block (4 Big 4 Small) - joe d (and wood sub-bases)
Bearing Block (4 Big 4 Small) - Dick L
Bearing Block (4 Big 4 Small) - Bob Warfield
Bearing Block (4 Big 4 Small) - Zuesrekning
Cylinder Shaft & Piston (8 Each) - ksouers
Cylinder Shaft & Piston (8 Each) - kustomkb
Cam Ring (16 Each) - GailinNM
Fly Wheel (8 Each) - kvom
Fly Wheel (8 Each) - Brass_Machine
Head (32 Each) - PowderKeg
Piston Rod & Fork (16 rods & 32 forks) - bretk
Rollers & Pin (32 rollers & 32 Pins) - JMe

Gail, since you have built this engine before... does this seem like a logical break down?

Eric

 

[Brass_Machine]

To help us keep organized in here, when posting about the build... please use the following in the subject:

for the Elmers OC:

TB1 - "insert your subject here"

and for the 2nd team build:

TB2 - "insert your subject here"

Many thanks
Eric

 

[Powder keg]

I'd like to do the heads.

Wes

 

[GailInNM]

Eric.

Looks OK to me except that you need 32 heads instead of 16. I will look at it again in the morning (after coffee) when I am a little more awake. The bearing block that acts as the valve block will need to be a close fit to the valve part on the cylinder, but I think that if we use a 1/2 inch end mill shank as a gauge pin to make the bearing block we will be OK if they are being bored. If they are reamed, then we should be able to just tolerance the mating part as it is easy to measure. Just a little coordination effort for the different people making them.

This only loosely relates to the team build, but I have been asked about the cam layout by people who are just interested in how it could be done manually easier than Elmer's way. I posted a zip file in the downloads section that has a Excel XLS file in it that can generate the cam coordinates for any size Coombers engine and a text file withe the coordinates for the Elmer's # 46 cam along with two ways of making it with out CNC. This is only for reference for the people who are interested in how it all works. Later I will post about how to draw them in CAD and to do them CNC if there is any interest.

Best wishes to all and looking forward to a very successful team build.
Gail In NM,USA

 

[Brass_Machine]

Eric.

Looks OK to me except that you need 32 heads instead of 16. I will look at it again in the morning (after coffee) when I am a little more awake. The bearing block that acts as the valve block will need to be a close fit to the valve part on the cylinder, but I think that if we use a 1/2 inch end mill shank as a gauge pin to make the bearing block we will be OK if they are being bored. If they are reamed, then we should be able to just tolerance the mating part as it is easy to measure. Just a little coordination effort for the different people making them.

This only loosely relates to the team build, but I have been asked about the cam layout by people who are just interested in how it could be done manually easier than Elmer's way. I posted a zip file in the downloads section that has a Excel XLS file in it that can generate the cam coordinates for any size Coombers engine and a text file withe the coordinates for the Elmer's # 46 cam along with two ways of making it with out CNC. This is only for reference for the people who are interested in how it all works. Later I will post about how to draw them in CAD and to do them CNC if there is any interest.

Best wishes to all and looking forward to a very successful team build.
Gail In NM,USA

Gail,

Thanks for the input! And thanks for uploading the XLS spreadsheet!

Eric

 

[Powder keg]

I'm interested in how you draw them in CAD Gail. So please post)

Wes

 

[JMe]

Hi
i propose to make rollers and pins
Regards from Belgium
Jacques

 

[Dick L.]

I'd like either Bearing blocks or Flywheels, your choice. ;D I have 6061 for the bearings blocks and I might have enough yellow brass for the flywheels but I need to check that out.
Thanks,
Dick

 

[kvom]

I'm thinking the flywheel might be doable by me with a bit of coaching.

Kirk

 

[ksouers]

I'll take a set of cylinder-shafts and pistons.

 

[bretk]

I'll take the piston rods and forks

-Bret

 

[kvom]

Any preference on the material for the flywheels: steel/brass/al?

 

[Brass_Machine]

Any preference on the material for the flywheels: steel/brass/al?

Added a poll for it.

Eric

 

[Dick L.]

Ok, I checked and I have 2" Brass for 16 flywheels I'll donate to the build if that's the way we go. It's made up of end cuts but the OD isn't marred up much.
Dick

 

[te_gui]

Let the modifications begin. While we are on the subject, I am thinking about changing the overall thickness of the base to 1/2" and increasing the footprint slightly so I can run a radius around the top edge. The additional thickness will allow for counterboring for socket head rather then flathead capscrews (hate them with a passion) as well as additional mass under the model which is never a bad thing. The outer dimensions will only increase enough for the radius so as to leave the bearing boys their original real estate. Any objections?

 

[Powder keg]

Sounds OK to me. What do the rest think?

Wes

 

[bretk]

Agree on the thicker base, I would also like to propose moving the flywheel outside of the second support, thus making it easier to see the piston movement and allow the flywheel and cam ring not to appear so cluttered and close. What does everyone think?

-Bret

 

[Brass_Machine]

Let the modifications begin. While we are on the subject, I am thinking about changing the overall thickness of the base to 1/2" and increasing the footprint slightly so I can run a radius around the top edge. The additional thickness will allow for counterboring for socket head rather then flathead capscrews (hate them with a passion) as well as additional mass under the model which is never a bad thing. The outer dimensions will only increase enough for the radius so as to leave the bearing boys their original real estate. Any objections?

Done!

I think that is a good idea.

Eric