Wormdrive sleeves

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misspentyouth62
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Wormdrive sleeves

Postby misspentyouth62 » Tue May 26, 2020 3:02 pm

Hi,
Would anyone know a source for sleeve tubing that would enable Romford worm drive which I believe are 3/32" bore, to fit instead on a 1.5mm motor spindle?

I have existing g/box and gears (50:1 I think?) and the simple fold-up gearbox neatly screws to the front of my new H1024 motor. Spindle passes through a 1.5mm top hat bearing in the g/box enclosure.

I do have some old stock (likely Exactoscale from memory) of motor adapter sleeves but these are only 10mm long with bore depth to 5mm only. I don't have engineering capability to drill right through as simple as that might be for most however.

Philip Hall
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Re: Wormdrive sleeves

Postby Philip Hall » Tue May 26, 2020 10:37 pm

Sleeves to step down a motor shaft are difficult to get completely true because of their length. A better idea is a pair of top hat bushes, one inserted in each end of the worm.

Old Romford gears (especially 50:1) were a bit of a lottery; a good set would run quite sweetly, but as Iain Rice once said, a bad set sounded like a concrete mixer full of granite boulders.

Only if you have a good set would it worth sourcing some bushes. Otherwise get a new set or better still, go to High Level or Branchlines for a gearbox.

The H1024 motor is the same as the old DS10, not a bad motor but very fast, designed thirty years or more ago for N gauge diesels. Again, there are more modern choices but possibly worth a try.

Philip

misspentyouth62
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Re: Wormdrive sleeves

Postby misspentyouth62 » Thu May 28, 2020 9:59 am

Thanks Philip - some good advice.

I guess I was looking to use what I already had on what is a low-quality model given today's standards and the motor I have is brand new and fits the fold-up gearbox that was bought for it at the time. I agree on the view of Romford gears btw, especially the larger ratio ones.

May I ask, (I've so far taken a look at High Level Models website and offerings which seem to offer lots of solutions to suit many configurations) do the gearboxes from High Level include the gears & worm with choice of bore size or only suited to their motor offerings which I as yet I haven't seen?

Cheers
Rob

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Will L
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Re: Wormdrive sleeves

Postby Will L » Thu May 28, 2020 10:29 am

misspentyouth62 wrote:...May I ask, (I've so far taken a look at High Level Models website and offerings which seem to offer lots of solutions to suit many configurations) do the gearboxes from High Level include the gears & worm with choice of bore size or only suited to their motor offerings which I as yet I haven't seen?

Highlevel gearbox/motor choices have always come with a variety of shaft and axle sizes, if you look at the price list he specifies shaft and axle sizes supported. This doesn't include 1mm shafts but given he now stocks motors with shafts that size, I would be surprised if he doesn't do that too now.

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Flymo748
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Re: Wormdrive sleeves

Postby Flymo748 » Thu May 28, 2020 4:53 pm

Will L wrote:
misspentyouth62 wrote:...May I ask, (I've so far taken a look at High Level Models website and offerings which seem to offer lots of solutions to suit many configurations) do the gearboxes from High Level include the gears & worm with choice of bore size or only suited to their motor offerings which I as yet I haven't seen?

Highlevel gearbox/motor choices have always come with a variety of shaft and axle sizes, if you look at the price list he specifies shaft and axle sizes supported. This doesn't include 1mm shafts but given he now stocks motors with shafts that size, I would be surprised if he doesn't do that too now.

Rob,

Easiest thing is to give Chris a call or drop him an email. He's an incredibly helpful chap, with a huge number of satisfied customers on here.

You'll also find him from time to time on here under the user name "High Level Kits", but Chris is very modest about what he does and his products.

HTH
Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

Philip Hall
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Re: Wormdrive sleeves

Postby Philip Hall » Thu May 28, 2020 9:53 pm

As far as I can remember the mounting screws on a H1024 are the same as on many can motors, so Chris at High Level should be able to help with a suitable gearbox. I would go for a fairly high ratio - 80:1 at least - as the motor is very high revving and is designed to run faster than many modern motors. I did actually put one into a 00 heavy cast GWR 44xx many years ago (with a 50:1 Romford gearset - a good one) and it ran quite well. I recall it did run quite hot though, probably having to lug all that weight around. The engine did come back to me some years ago and will eventually go into shops for conversion to P4.

Probably worth a try, if the motor doesn’t suit it would be fairly easy to swap later on.

Philip

David Catton
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Re: Wormdrive sleeves

Postby David Catton » Thu Jun 04, 2020 7:40 pm

Out of interest, does anyone know of sources of suitable turned bushes:

2.0mm OD x 1.0mm ID
2.0mm OD x 1.5mm ID
1.5mm OD x 0.78mm ID

My reason for asking is that I have purchased a variety of very cheap motors that I wish to try in various locos and while I can always ask Chris at High Level for extra worm gears, thought it might be worth seeing if there is anything available (at attractive prices) that would permit the supplied/ordered worm (say, for a 2mm diameter shaft) to be sleeved to permit trials with motors having various shaft diameters, e.g. 1.5mm, 1.0mm and 0.78mm! I'm thinking of turned bushes because of Philip Hall's recommendation in an earlier post that turnings rather than brass tube are to be preferred.

Keep on keeping safe . . .

David C

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Paul Townsend
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Re: Wormdrive sleeves

Postby Paul Townsend » Fri Jun 05, 2020 5:22 am

David Catton wrote:Out of interest, does anyone know of sources of suitable turned bushes:

2.0mm OD x 1.0mm ID
2.0mm OD x 1.5mm ID
1.5mm OD x 0.78mm ID

My reason for asking is that I have purchased a variety of very cheap motors that I wish to try in various locos and while I can always ask Chris at High Level for extra worm gears, thought it might be worth seeing if there is anything available (at attractive prices) that would permit the supplied/ordered worm (say, for a 2mm diameter shaft) to be sleeved to permit trials with motors having various shaft diameters, e.g. 1.5mm, 1.0mm and 0.78mm! I'm thinking of turned bushes because of Philip Hall's recommendation in an earlier post that turnings rather than brass tube are to be preferred.

Keep on keeping safe . . .

David C



ISTR that Wizard or Branchlines or Markits have had the first two. Last one ...no chance! You might find 1.5 x .5 and then ream.

Worth a look at AliExpress.....

bécasse
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Re: Wormdrive sleeves

Postby bécasse » Fri Jun 05, 2020 8:53 am

0,78 mm sounds suspiciously like 1/32 inch (which I would have described as 0,79 mm), for the US market perhaps. You might just find a 1/16"-1/32" bush and, although 1/16" is closer to 1,6 mm than 1,5 mm, you could probably ream the worm out to allow it to fit.

David Catton
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Re: Wormdrive sleeves

Postby David Catton » Fri Jun 05, 2020 11:38 am

Thanks for the suggestions. I think Phoenix Precision supply bushes (when in stock!) that should be OK for the 2mm x 1.5mm and 2mm x 1.0mm sizes. The smaller one may need fettling as suggested.

I also tried Markits, Alan Gibson, Wizard, Roxey, eBay, Alibaba and Aliexpress before asking on here but if anyone comes across alternative sources, I'd appreciate details.

ATB,

David C

Terry Bendall
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Re: Wormdrive sleeves

Postby Terry Bendall » Sun Jun 07, 2020 9:39 am

David Catton wrote:if anyone comes across alternative sources, I'd appreciate details.


One alternative is to find someone with a lathe and persuade them to make some for you. :)

bécasse wrote:0,78 mm sounds suspiciously like 1/32 inch


0.78 mm is 0.0307 inches. A number 68 drill, if you can get one is 0.0310 inches. 1/32 is 0.0312 inches as a decimal so probably too much clearance for the size and the application.

Terry Bendall

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Paul Townsend
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Re: Wormdrive sleeves

Postby Paul Townsend » Sun Jun 07, 2020 1:03 pm

Terry Bendall wrote:
David Catton wrote:if anyone comes across alternative sources, I'd appreciate details.


One alternative is to find someone with a lathe and persuade them to make some for you. :)

bécasse wrote:0,78 mm sounds suspiciously like 1/32 inch


0.78 mm is 0.0307 inches. A number 68 drill, if you can get one is 0.0310 inches. 1/32 is 0.0312 inches as a decimal so probably too much clearance for the size and the application.

Terry Bendall

If I were faced with this and had a 1/3" parallel reamer I would go for it. Surely a shaft at .0307 in a hole at .0312 with a dribble of loctite would self centre ? Worth a try and if it doesnt a bit of heat will enable removal...be quick before you wreck the motor....use a heatsink between the trial top hat bearing and the motor bearing. A slow manual spin against a dial guage would enable evaluation after it has cured.

Terry Bendall
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Re: Wormdrive sleeves

Postby Terry Bendall » Mon Jun 08, 2020 8:11 am

Paul Townsend wrote:If I were faced with this and had a 1/3" parallel reamer I would go for it.


The problem Paul might be in finding a reamer of that size. I double if such a size exists. A new drill of the correct size should be sufficiently accurate.

Paul Townsend wrote: Surely a shaft at .0307 in a hole at .0312 with a dribble of loctite would self centre ?


On a good day, with a following wind perhaps. Sod's Law says it won't. :(

Paul Townsend wrote:A slow manual spin against a dial guage would enable evaluation after it has cured.


First hold your dial gauge firmly in place so it cannot move. Then find a support for the motor so that can be held firmly in the right place. Then spin the shaft. It might be done, but not easily. :)

Terry Bendall

davebradwell
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Re: Wormdrive sleeves

Postby davebradwell » Mon Jun 08, 2020 8:27 am

Well I found a reamer - £26-70. A hand reamer has a long lead taper so could be used to create a press fit - it's how locating dowels are fitted. All you have to do then is create another press fit in the worm so there's another tight tolerance. It's just not worth it. The motor would have to be something very special to be worth all this trouble and the 1/32" shaft running in tiny bearings with an overhanging worm isn't going to take much load.

DaveB

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Will L
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Re: Wormdrive sleeves

Postby Will L » Mon Jun 08, 2020 9:46 am

Terry Bendall wrote:
Paul Townsend wrote: Surely a shaft at .0307 in a hole at .0312 with a dribble of loctite would self centre ?


On a good day, with a following wind perhaps. Sod's Law says it won't. :(

Given that total failure gives an off centre error of .0025, is that sufficient for to us to care?

Alan Turner
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Re: Wormdrive sleeves

Postby Alan Turner » Fri Jun 12, 2020 11:18 pm

If you have a shaft of 0.78mm (0.0307") and a hole of 0.7925mm (0.0312"). Then you have 0.0125mm (0.0005") clearance. That is well within the tolerance/requirement of a sliding fit. In fact it's a bit tight - you may have difficulty getting it on.

regards

Alan

davebradwell
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Re: Wormdrive sleeves

Postby davebradwell » Sat Jun 13, 2020 8:27 am

The only trouble with all this is that you haven't a hole of 0.7925mm, there is a drill around that size and the rest is speculation/wishful thinking. We're not really sure how big the shaft is either until someone puts a Mike on it.

DaveB

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zebedeesknees
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Re: Wormdrive sleeves

Postby zebedeesknees » Sat Jun 13, 2020 9:19 am

I found that 0.8mm drill bits are not all the same diameter, and the speed may govern the size of the hole, to a fraction of a thou. When drilling pulleys for micromotors from Nigel Lawton, powering the lathe produced a sliding fit, whereas turning the chuck by hand with the same bit produced a tight interference fit. So tight that pressing the pulley onto the shaft pushed the armature out of the back of the motor!

Subsequently, the motor shaft was pushed into the pulley from the back with the blunt end of a 3mm bit.

Ted.

Enigma
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Re: Wormdrive sleeves

Postby Enigma » Sat Jun 13, 2020 12:06 pm

Will L wrote:
Terry Bendall wrote:
Paul Townsend wrote: Surely a shaft at .0307 in a hole at .0312 with a dribble of loctite would self centre ?


On a good day, with a following wind perhaps. Sod's Law says it won't. :(

Given that total failure gives an off centre error of .0025, is that sufficient for to us to care?


Certainly no worse (and probably a lot better) than the tolerances on some items from the trade BITD.

Terry Bendall
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Re: Wormdrive sleeves

Postby Terry Bendall » Sun Jun 14, 2020 9:40 am

zebedeesknees wrote:I found that 0.8mm drill bits are not all the same diameter,


As Ted says, he size of a drill can vary and it will depend on how well the point is ground. In larger sizes, say over 2mm dia. this is easy to see but more of a challenge in the sizes we are discussing here. It would depend on how carefully the drill manufacturer was and the cost of what you paid will influence this.

Terry Bendall


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