Electric Traction Engine

[JasonBModerator @jasonb]

That is how the full size were done but takes quite a set up to do on a model and your Tee section will be half hard brass so not easy to bend.

Have a look through the first couple of pages here to see some 4" scale wheels being rolled from tee.

Most people use a rolled rim from flat stock and weld in a "washer" to form the tee. If you can find it then tube works too, possibly on your size cut from a propane/butane cylinder suitably purged first. or ERW tube at least for the fronts.

[Ron LadenParticipant @ronladen17547]

Thanks Jason, I cant open the link for some reason so havnt had a look.

Ron

[Anonymous]

Posted by Ron Laden on 18/11/2018 08:33:39:

Andrew, why two engines ? are you building the second one for someone else, sorry I am just been nosey.

When I visited the casting supplier for my engines, before committing to purchase, I was told it doesn't take twice as long to build two engines, only an extra 30%. So I hatched a plot to build two, keep one and sell the other. Now that I'll be fitting one with rubber tyres and one with steel wheels I may well end up keeping both, at least in the short term. I think that the 30% extra is a bit optimistic, it's more like 45%. But it's true in that some time is taken making fixtures and setting up, and I spend a lot of time drawing and redesigning parts, both of which are independent of the number of engines.

Andrew

[Ron LadenParticipant @ronladen17547]

Having spent most of the winter making and adding mods to the mill and lathe its time to get back to some modelling, still more mods to do but they can wait.

I fancy some milling and turning so I am going to start with a set of axle and shaft bearings. I have serviced the rotary table and have a 100mm 4 jaw independent on the way from ARC. The bearings will be copies of the Minnie type, just scaled up to 1.625". I was going to make them in bronze but I have decided to use cast iron which I understand is a good bearing material, also got 3 sizes of ground steel rod on the way for the shafts and axle.

Will see how they turn out.

Ron

[Ron LadenParticipant @ronladen17547]

For the bearings I need the RT with a chuck so I am pinching the lathe 3 jaw. I just need to make a square mounting plate for it, 3 off allen csk screws will pick up in the M8 chuck fixing holes. The plate can then be fastened down to the table using the 4 Tee slots. Also need to turn up a stepped spigot to centre the chuck to the table, should work out ok.

[JasonBModerator @jasonb]

Ron have you thought of mounting your vice on the rotary table and then hold the rectangular flange of the bearings while you mill the teardrop shape.

[Ron LadenParticipant @ronladen17547]

Posted by JasonB on 16/03/2019 08:54:46:

Ron have you thought of mounting your vice on the rotary table and then hold the rectangular flange of the bearings while you mill the teardrop shape.

No, I didnt give that a thought Jason, I was thinking of holding the bearing by the boss in the 3 jaw. I can see that mounting the vice a good idea, thanks for that.

Whilst talking bearings Jason have you any thoughts on my using cast iron, I couldnt think of any reason why not but with your experience you may think differently.

Ron

[JasonBModerator @jasonb]

Should be fine, the other option that is cheaper than cutting from solid bronze is to use steel and fit a bronze bush, CI will be the quicker build as its easier to machine.

[Ron LadenParticipant @ronladen17547]

Posted by JasonB on 16/03/2019 16:08:39:

Should be fine, the other option that is cheaper than cutting from solid bronze is to use steel and fit a bronze bush, CI will be the quicker build as its easier to machine.

Thanks Jason

[Ron LadenParticipant @ronladen17547]

Jason, re the vice mounted on the RT, probably me being a bit dumb but how do you centre the workpiece to the RT centre..?

[JasonBModerator @jasonb]

Some packing between work and fixed jaw is often needed and the final adjustment made with the play around the two vice fixings. Will post a photo when I'm in later.

[JasonBModerator @jasonb]

Here you go, the bolt slots on my vice are about 1" from the jaws so to be able to bolt it to the rotary table any work needs to be packed so that the ctr of the work is approx 1" from the fixed jaw. This valve chest is 3/4" thick so 3/8" to ctr and you can see I have added 1/2" and 1/8" packing to bring the total to 1". You can the n slide the vice around for the last small adjustments to bring your ctr mark or hole below the spindle.

[Ron LadenParticipant @ronladen17547]

Thanks for that Jason, just checked my vice and it is a bit more 1.312" from bolt slots to fixed jaw so need to adjust accordingly.

[Ron LadenParticipant @ronladen17547]

I am in need of some bedside reading, any recommendations for a good beginners guide to gear cutting..? I see No 17 in the workshop practice series covers gears – gear cutting so was thinking of getting that one.

I was going to buy in the gears but with a RT coming with a dividing set I would like to have a try at producing my own. Not knowing much about it but the RT set is 3 plates 15 – 49 and I am going with MOD 1.5 and 2.0 gears so hoping the plates cover those.

Ron

[JasonBModerator @jasonb]

Without knowing the number of teeth on your gearwheels its impossible at this stage to say if you will have the divisions needed. You may find it easier on the SX2 to stick with MOD1.5 and just cut a few more teeth

Edited By JasonB on 19/03/2019 08:00:18

[Ron LadenParticipant @ronladen17547]

Posted by JasonB on 19/03/2019 07:42:34:

Without knowing the number of teeth on your gearwheels its impossible at this stage to say if you will have the divisions needed. You may find it easier on the SX2 to stick with MOD1 and just cut a few more teeth

Jason, is your thinking that MOD 1.5 and 2.0 could be too heavy for the mill..?

[JasonBModerator @jasonb]

I meant to type 1.5, yes I think MOD2 may be a bit of a strain.

[Ron LadenParticipant @ronladen17547]

A compromise could be to buy in the Mod 2 – 80T, 25T and the motor 12T and then make the Mod 1.5 gears. If I have got it right it would mean 5 cutters to cover the 15,20,25,30 and 50T gears.

Just looked at cutters and that seems a bit of a mine field, I saw a set of eight Mod 1.5 cutters at over £700 down to a Chinese set of eight for £56 (dont fancy those). Looking at the cutters individually, I found some at £22 each and I,m guessing that is maybe the going rate for something half decent..?

[JasonBModerator @jasonb]

Should be able to get the 20 & 25 from the same cutter.

Also worth doing the sums for what it would cost to buy the MOD1.5 gears over the cost of a cutter, you could pick those smaller gears up for around £5 from someone like Beltingonline but if you wanted to have a go at cutting then make the larger ones where the gear and cutter costs are about the same

[Ron LadenParticipant @ronladen17547]

That makes sense Jason.

[Ron LadenParticipant @ronladen17547]

Well if I just go by the sums then it is really a no brainer, I can get a full set ot Mod1.5 gears from China for £60. There would be a risk in what you receive but I have had gears from China in the past and they were very good. They are thicker than I need so will need machining down but that shouldnt be an issue.

I can always save my gear cutting practice for a later date.

Edited By Ron Laden on 21/03/2019 08:18:41

[Ron LadenParticipant @ronladen17547]

Thinking ahead, and where appropriate on the engine I would like to go with studs and nuts and not set screws. I know they can be made up with the nuts fixed to the stud with a couple of threads protruding (looks good) and then used like set screws. I could be wrong but I think the studs and nuts are often fixed together by silver soldering..? I was wondering if Loctite 638 retainer would work or is it not strong enough..? One of the first fixing jobs will be the horn plates probably 5BA or 4BA with one size smaller nuts.

It was just a thought.

Ron

[JasonBModerator @jasonb]

Depends if you want it to look like areal engine in which case all that lot should be rivited

Button heads may be a good compromise

[Paul KempParticipant @paulkemp46892]

Ron,

As Jason says horn plates are normally rivetted, in fact on FS engines they are often an upward extension of the firebox sides and the centre 'rivets' you see are actually the knocked up ends of the boiler stays, the ones around the edges being the rivets holding the boiler plates together. On models it is normal to have a small number of screwed fixings (6 or 8 per side) and button head Allen screws are good for that, the socket can be filled after fitting if you wish and the rest are dummy rivets. I am pretty sure some of the kit manufacturers just advocate loctiteing plain shank round head rivets in suitable clearance holes. With yours being cold this would be fine.

Paul.

[Ron LadenParticipant @ronladen17547]

Posted by JasonB on 28/03/2019 17:50:59:

Depends if you want it to look like areal engine in which case all that lot should be rivited

Button heads may be a good compromise

That just reinforces something I thought the other day, I need to spend an hour with a full size engine armed with my camera.

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