16mm IDRIS

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16mm IDRIS

This topic has 182 replies, 13 voices, and was last updated 12 May 2016 at 20:15 by John Rudd.

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10 June 2015 at 17:34 #192971
Alex Collins
Participant
@alexcollins55045
Hi All

I'm now back from my jaunt around the Med. Should be back in the workshop over the coming days.
Just ordered some cogs. 32 and 48 dp in a range of sizes.
Next CSME night is next week. I'll take em the Boiler and ask them to be gentle with me…..

Still debating the make / buy wheels thing. I have the stock so will probably have a go.
That eccentric certainly looks fun to make. Done a few before in the 4 jaw so not expecting any issues.
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12 June 2015 at 13:48 #193143
martin ranson 2
Participant
@martinranson2
IDRIS DRAWING ERROR … in part 4 of the series, at the bottom of page 872 is figure 16 … there are 3 references to 7 BA threads … these should read 6 BA … the text alongside the drawing correctly reads 6 BA … cannot blame the gremlins for this one … my fault.

martin
12 June 2015 at 22:27 #193197
Alex Collins
Participant
@alexcollins55045
Hi Martin. I had already worked that one out. I have 6 BA screws and they all fit as expected.
I will comment that this makes the crank pin bushes very thin. I may go up a bit on the ID of the bushes.
16 June 2015 at 19:04 #193767
Alex Collins
Participant
@alexcollins55045
16 June 2015 at 19:57 #193772
Alex Collins
Participant
@alexcollins55045
I'm wondering where the text went that was with the photo….

4 wheels started.

Boss is 16mm dia X 11mm long. may well reduce this later. It's 16mm cos I have a 16mm Collet.

I turned the boss taking ~ 2mm cuts down to 17mm dia then cleaned it all up. The myford was quite happy with this.
Parted them off at 7mm with a 2mm wide tool. It really didn't like that much.
The tool dug in several times during each cut. The clutch I fitted has proven most valuable.
Tried everything including regrinding the tool.

I'll put the boss into the Collet chuck to drill the hole and turn the tread. That should keep it all concentric.
What sort of angles do I need on the flange and tread ?
17 June 2015 at 08:22 #193826
martin ranson 2
Participant
@martinranson2
Morning Alex … welcome back … wow ! a 2 mm cut in steel is very impressive, I am pretty sure my small lathe would be struggling … how far away from the chuck were you cutting when doing the parting-off ?

As regards the angles on the wheels … I am not the worlds best expert on railway practices … what I have found out varies with who I ask … the angle between the tread and the flange is a bit bigger than 90 degrees … the tread is not parallel, it is slightly coned by about 3 – 6 degrees … the flange is not vertical, it is tipped inwards towards the middle of the track by 6 – 14 degrees, typically 10 degrees … where the tread meets the flange is sometimes a sharp corner and sometimes a very small radius, about 0. 5 to 1mm … the flange depth for 32 mm seems to be about 2 – 3 mm.

If all else fails, try and measure the commercial wheels you have bought … hope this is some use.

martin
17 June 2015 at 11:59 #193854
John Bromley
Participant
@johnbromley78794
The standards for wheel profiles are on the 16mm narrow gauge modellers website.
I believe they are under downloads.
John
17 June 2015 at 18:16 #193891
Alex Collins
Participant
@alexcollins55045
Hi Martin.

I cut off 100 mm of bar. That gave me enough for 4 wheels + the option of a 5th.
For the first 2 I used a steady + the centre. The 2nd pair I ditched the centre.

Cleaned the lathe tonight. The parting issues were probably caused by the lash in the cross slide getting sucked in.
I'll add in a bit of friction on the slide locks next time….

John. Will wonder over to that site and have a look.

Thanks
18 June 2015 at 06:56 #193955
martin ranson 2
Participant
@martinranson2
Alex … just a P.S. to my words above … some of the commercial wheels I bought a few years ago only had a small flange … I did not realise at the time … the depth was less than 1. 5 mm ( actually 0. 055 inches ) … the wagon with those wheels would occasionally leap skywards passing over a point … problem ceased when I managed to re-cut the flange a bit deeper …maybe 2 mm is a decent minimum depth ?

I have just been given a long list of jobs from SWMBO, so I will be busy for a few days … have to turn the lathe off for a while !!! horror !!! back soon.

martin
21 June 2015 at 18:59 #194357
Alex Collins
Participant
@alexcollins55045
Wheels complete. Just need to drill and tap for the grub screws.
22 June 2015 at 06:53 #194403
Steven Greenhough
Participant
@stevengreenhough56335
Wheels look good Alex.
23 June 2015 at 18:50 #194631
Alex Collins
Participant
@alexcollins55045
You may have to forgive me this one.
Fig 17, Page 873.
The drawing for the eccentric says:
Throw 0.236
Center offset half of this = 0.118
That's fine.
I get a bit of round bar Offset it by 0.118.

What size round bar do I start with ? ( or what size is the lobe )
23 June 2015 at 18:59 #194632
JasonB
Moderator
@jasonb
0.625" – 5/8"

There is a clue written just under the big bold "Eccentric" print
23 June 2015 at 20:47 #194647
Alex Collins
Participant
@alexcollins55045
DOH!
Thankyou Jason
27 June 2015 at 11:12 #195104
martin ranson 2
Participant
@martinranson2
Morning Alex … like the look of the 4 wheels … I do not know if this is any use to you … the commercial wheels I bought had a thickness of approx. 0. 474 inches ( 12. 03 mm ? ) … they were not all exactly the same … I varied the size of the bearing bushes to match the individual wheels … you may have to do something similar … I positioned the wheels at the correct distance apart and worked backwards to get the width of the final drive gear ( fig 5 page 590, fig 17 and 18 page 873&nbsp

martin
4 July 2015 at 23:00 #195785
Alex Collins
Participant
@alexcollins55045
Spoke to the Boiler man today. CSME had a members open day.
He is happy with the general construction and soldering. As expected commented that the 2 top bushes were not up to standard.
I need to re flux them and get the solder that is on them to flow. At that point the boiler should be fine.
Spoke in detail and it's obvious to me that my Hearth is not good enough. I should have enough heat with the tools I have but the heat is escaping.

The frame also got favourable comments. Picked up some tips on the motion bars. I need to make them on a jig.

Some great Models on display and running. Guy had his first run in a polly. The grin went full circle.
6 July 2015 at 18:31 #195965
Alex Collins
Participant
@alexcollins55045
I now have smooth motion.
Centre Popped a Jig through the frame rails. Ground up a bit of 1/4" silver steel to a point.
Soft soldered the rods (to the jig as well most of the time). Took a few goes to get them right.
Making Bushes to go over 6BA screws (2.6mm ID / 1/8" OD) was not going to be easy. I also think the crush factor as we do up the screws may be rather high.
Drilled the motion rods 4mm and made some shouldered screws.
8mm OD Head. 4 mm shank for the bushes to run in 6BA Thread for the crank arms.

Motion was a tad sticky so drilled the bushes to 4.2mm and all is good.

Wheels all line up but I don't have a suitable track or place to put the track.
The CSME (Chelmsford society of Model engineers) Track will allow me to run between gauges if I shorten the axle bushes.
7 July 2015 at 13:41 #196044
martin ranson 2
Participant
@martinranson2
Alex … a question about your letter above … does this mean you are using the rails for 2 1/2 and 3 1/2 inch tracks or does it mean you are using the rails for 3 1/2 and 5 inch tracks please ?? if you eventually get your own 32 mm track does it mean the bushes will need to be remade a different length ??

Does it mean you may need some new spacers to hold everything in place along the 2 axles ??

martin
7 July 2015 at 17:04 #196054
Alex Collins
Participant
@alexcollins55045
Hi Martin.
The Chelmsford Track has 3 1/2", 5" and 7 1/4" Tracks.
None of these gauges are suitable – they are to wide.

My Thoughts are, with narrower Axle spacers I can move the wheels apart and run on the track between the 5" and 7 1/4" gauges.
I'm aware that running on these rails would be totally unsupported but briefly spoke to a member who has done just that.
I did intend to measure the actual gaps last weekend. I forgot to take a suitable measuring stick.

Maybe my ideas are crazy at times…………
7 July 2015 at 17:14 #196056
Steven Greenhough
Participant
@stevengreenhough56335
Is there not a 1 1/4 inch gap between the 3.5 and 5 inch rail that you can run a 32mm wheelset on?
7 July 2015 at 18:32 #196067
Alex Collins
Participant
@alexcollins55045
I need to go measure. Until I do that nothing is final….
8 July 2015 at 17:23 #196157
Alex Collins
Participant
@alexcollins55045
Wot no bits to make in the latest edition !
8 July 2015 at 20:42 #196181
Steambuff
Participant
@steambuff
Alex,

Where are you based? Is their another club nearby that has a 32/45mm track?

or Join the 16mm Association, they have quite a few members lines in the Chelmsford area

Dave

Edited By Steambuff on 08/07/2015 20:44:11
8 July 2015 at 22:13 #196199
Alex Collins
Participant
@alexcollins55045
I'm in Chelmsford in Essex.
If there is another club I'm not aware of them.
8 July 2015 at 22:45 #196204
Steven Greenhough
Participant
@stevengreenhough56335
The 16mm Narrow Gauge association may be able to direct you to somewhere suitable? A lot of garden running goes on for the small scales. Not sure exactly what yearly membership is but it’s in the region of ?20 and the quarterly mags and the excelent starter guide are easily worth the cash.

Might be worth a punt.

Also, don’t know how you are for space at home but Peco SM32 track is flexible to bend to as tight a curve as you need (loco accepting of course)… failing that the minimum set-track radius is 2ft 6. Two boxes and a couple of lengths of the flex could get you a little temporary oval to try out on?
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