Shemarah II

[Bob Abell 2Participant @bobabell2]

Hello Gareth

Looking at the threaded shaft…….It happens to be a left and right hand groove and not a thread, it is used for a reciprocating motion

To do it properly would be very difficult, as the threads are contious…..and don't break out at the ends

What are the dimensions please?

Bob

[Bob Abell 2Participant @bobabell2]

Hello Gareth

Looking at the threaded shaft…….It happens to be a left and right hand groove and not a thread, it is used for a reciprocating motion

To do it properly would be very difficult, as the threads are contious…..and don't break out at the ends

What are the dimensions please?

Bob

[Gareth JonesParticipant @garethjones79649]

Hi Bob,

I can see I have got your attention now and this is looking like a challenge to your turning skills

The dimensions of the shaft I have made are as follows.

Its 64 mm long (between the inside faces of the winch sideplates.)

Its made from 4 mm OD styrene tube with a 2 mm bore

A length of 2 mm diam cocktail stick is inserted in each end of the tube and protrudes by about 1 mm to act as a spigot locating the shaft in the sideplates.

The length of the grooved section would be about 56 mm, scaled from the photo.

Regards

Gareth

[Gareth JonesParticipant @garethjones79649]

Hi Bob,

I can see I have got your attention now and this is looking like a challenge to your turning skills

The dimensions of the shaft I have made are as follows.

Its 64 mm long (between the inside faces of the winch sideplates.)

Its made from 4 mm OD styrene tube with a 2 mm bore

A length of 2 mm diam cocktail stick is inserted in each end of the tube and protrudes by about 1 mm to act as a spigot locating the shaft in the sideplates.

The length of the grooved section would be about 56 mm, scaled from the photo.

Regards

Gareth

[Gareth JonesParticipant @garethjones79649]

Hi Bob,

I can see I have got your attention now and this is looking like a challenge to your turning skills

The dimensions of the shaft I have made are as follows.

Its 64 mm long (between the inside faces of the winch sideplates.)

Its made from 4 mm OD styrene tube with a 2 mm bore

A length of 2 mm diam cocktail stick is inserted in each end of the tube and protrudes by about 1 mm to act as a spigot locating the shaft in the sideplates.

The length of the grooved section would be about 56 mm, scaled from the photo.

Regards

Gareth

[Bob Abell 2Participant @bobabell2]

Hi Gareth

I'll will need to look into the lead screw gearing to get about a 4mm pitch

Will let you know

Haven't done screw cutting on this lathe before

Bob

[Bob Abell 2Participant @bobabell2]

Hi Gareth

I'll will need to look into the lead screw gearing to get about a 4mm pitch

Will let you know

Haven't done screw cutting on this lathe before

Bob

[Bob Abell 2Participant @bobabell2]

Hi Gareth

I'll will need to look into the lead screw gearing to get about a 4mm pitch

Will let you know

Haven't done screw cutting on this lathe before

Bob

[Gareth JonesParticipant @garethjones79649]

Hi Bob

The last time I operated a lathe would have been during my university work experience sessions, at Renold Chains in Manchester in 1971 and the Royal Ordnance Factory in Chillwell Notingham in 1972. I have to admit I would be a bit rusty now.

Gareth

[Gareth JonesParticipant @garethjones79649]

Hi Bob

The last time I operated a lathe would have been during my university work experience sessions, at Renold Chains in Manchester in 1971 and the Royal Ordnance Factory in Chillwell Notingham in 1972. I have to admit I would be a bit rusty now.

Gareth

[Gareth JonesParticipant @garethjones79649]

Hi Bob

The last time I operated a lathe would have been during my university work experience sessions, at Renold Chains in Manchester in 1971 and the Royal Ordnance Factory in Chillwell Notingham in 1972. I have to admit I would be a bit rusty now.

Gareth

[Bob Abell 2Participant @bobabell2]

Hello Gareth

Sorry, Gareth……Can't do it!

The groove would need to be 1mm x 1mm, leaving a core of only 2mm and it would be to weak for turning

Sorry to raise your hopes, at the moment I can't think of a way round it either

You could wrap adhesive tape round with a 4mm pitch and mark the plastic rod with Indian ink, then do it again, opposite hand, but the end of the threads is not easy

Perhaps, as it is now, would be the neatest option?

Bob

[Bob Abell 2Participant @bobabell2]

Hello Gareth

Sorry, Gareth……Can't do it!

The groove would need to be 1mm x 1mm, leaving a core of only 2mm and it would be to weak for turning

Sorry to raise your hopes, at the moment I can't think of a way round it either

You could wrap adhesive tape round with a 4mm pitch and mark the plastic rod with Indian ink, then do it again, opposite hand, but the end of the threads is not easy

Perhaps, as it is now, would be the neatest option?

Bob

[Bob Abell 2Participant @bobabell2]

Hello Gareth

Sorry, Gareth……Can't do it!

The groove would need to be 1mm x 1mm, leaving a core of only 2mm and it would be to weak for turning

Sorry to raise your hopes, at the moment I can't think of a way round it either

You could wrap adhesive tape round with a 4mm pitch and mark the plastic rod with Indian ink, then do it again, opposite hand, but the end of the threads is not easy

Perhaps, as it is now, would be the neatest option?

Bob

[Gareth JonesParticipant @garethjones79649]

Hi Bob,

Thanks for trying, these little challenges are what makes modelling so interesting.

At the moment my thoughts are either to try wrapping some thin black trimline around the shaft in the shape of the groove (but that is going to be difficult to place accurately). Alternatively print the shape on to a thin piece of paper and glue it to the shaft with the joint along the bottom where it can't be seen. I think the groove would be a series of straight lines when 'opened out' onto the flat sheet of paper so that option might be easiest.

Either way the shaft can be removed fairly easily at any stage so I can rework it later if I find a better way to do it.

Regards

Gareth

[Gareth JonesParticipant @garethjones79649]

Hi Bob,

Thanks for trying, these little challenges are what makes modelling so interesting.

At the moment my thoughts are either to try wrapping some thin black trimline around the shaft in the shape of the groove (but that is going to be difficult to place accurately). Alternatively print the shape on to a thin piece of paper and glue it to the shaft with the joint along the bottom where it can't be seen. I think the groove would be a series of straight lines when 'opened out' onto the flat sheet of paper so that option might be easiest.

Either way the shaft can be removed fairly easily at any stage so I can rework it later if I find a better way to do it.

Regards

Gareth

[Gareth JonesParticipant @garethjones79649]

Hi Bob,

Thanks for trying, these little challenges are what makes modelling so interesting.

At the moment my thoughts are either to try wrapping some thin black trimline around the shaft in the shape of the groove (but that is going to be difficult to place accurately). Alternatively print the shape on to a thin piece of paper and glue it to the shaft with the joint along the bottom where it can't be seen. I think the groove would be a series of straight lines when 'opened out' onto the flat sheet of paper so that option might be easiest.

Either way the shaft can be removed fairly easily at any stage so I can rework it later if I find a better way to do it.

Regards

Gareth

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Hi Gareth

here's my tuppence worth

could you coat up a brass rod to be the diameter required with P38 and then file in the thread into the polymer coating?

It's take a bit of work but as it only has to look the part why does it have to be all metal?

I note that its already a plastic tube anyway, so maybe use one 1mm smaller and coat up by 1mm?

Kim. (guaranteed daft solutions)!

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Hi Gareth

here's my tuppence worth

could you coat up a brass rod to be the diameter required with P38 and then file in the thread into the polymer coating?

It's take a bit of work but as it only has to look the part why does it have to be all metal?

I note that its already a plastic tube anyway, so maybe use one 1mm smaller and coat up by 1mm?

Kim. (guaranteed daft solutions)!

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Hi Gareth

here's my tuppence worth

could you coat up a brass rod to be the diameter required with P38 and then file in the thread into the polymer coating?

It's take a bit of work but as it only has to look the part why does it have to be all metal?

I note that its already a plastic tube anyway, so maybe use one 1mm smaller and coat up by 1mm?

Kim. (guaranteed daft solutions)!

[Gareth JonesParticipant @garethjones79649]

Hi Kim,

Thats another possible solution but I think the difficult bit would be filing the groove neatly in the P38 as its so narrow I think the edges would tend to get chipped and rounded. I guess the real groove is no more than 10 mm wide so at 1:24 it would be around half a mm. On details like this the scale size is not that critical but I think the neatness of the finish would be what makes or breaks the appearance of the part.

Thanks for the suggestion, I will add it to my list to consider. I am just making up hydraulic pipes at the moment while pondering the lead screw problem.

Regards

Gareth

[Gareth JonesParticipant @garethjones79649]

Hi Kim,

Thats another possible solution but I think the difficult bit would be filing the groove neatly in the P38 as its so narrow I think the edges would tend to get chipped and rounded. I guess the real groove is no more than 10 mm wide so at 1:24 it would be around half a mm. On details like this the scale size is not that critical but I think the neatness of the finish would be what makes or breaks the appearance of the part.

Thanks for the suggestion, I will add it to my list to consider. I am just making up hydraulic pipes at the moment while pondering the lead screw problem.

Regards

Gareth

[Gareth JonesParticipant @garethjones79649]

Hi Kim,

Thats another possible solution but I think the difficult bit would be filing the groove neatly in the P38 as its so narrow I think the edges would tend to get chipped and rounded. I guess the real groove is no more than 10 mm wide so at 1:24 it would be around half a mm. On details like this the scale size is not that critical but I think the neatness of the finish would be what makes or breaks the appearance of the part.

Thanks for the suggestion, I will add it to my list to consider. I am just making up hydraulic pipes at the moment while pondering the lead screw problem.

Regards

Gareth

[LARRY WHETTONParticipant @larrywhetton68737]

Hi Garath,

You migth try a fine spring , strechch a littel 1 left and right on a cross over bacis,

or a plated hot wire , done with all the elf and safty , sounds daft but might work ,

a pratice piece might help , well done on great detail gold medel standered,

enjoying blog , and some great in put by others………..cheers Larry….

Edited By LARRY WHETTON on 10/05/2013 20:32:31

[LARRY WHETTONParticipant @larrywhetton68737]

Hi Garath,

You migth try a fine spring , strechch a littel 1 left and right on a cross over bacis,

or a plated hot wire , done with all the elf and safty , sounds daft but might work ,

a pratice piece might help , well done on great detail gold medel standered,

enjoying blog , and some great in put by others………..cheers Larry….

Edited By LARRY WHETTON on 10/05/2013 20:32:31

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