Broad Ambition - The Model

[LondonRascal]

This might be at a scale version but I know these issues have been found in real life when a new engine might come out and thrust and vibration loads on bearings, couplings and ear boxes and how mounts the engine is on down to the fly wheel size and mass all mean this is a 'dark art' to get right. It not just boat building but true engineering and fascinating to follow. 

[grendel]

Yes, and the vibration is no different when you have tiny prop shafts but they are revolving at 11,000 rpm, and much much worse at 20,000 rpm, the slightest imbalance at these speeds, makes for a lot of vibration. I will see what I have to work with tonight.

[grendel]

a little testing, I have replaced the coupling with a length of hose, and its a bit quieter, I have ordered some silicon tube in the correct size, this should make even more difference, as the hose I found was old and stiff, so not the best test

[FairTmiddlin]

22 hours ago, grendel said:

 old and stiff, so not the best

That's me down to a Tee

 

[grendel]

Tonight, instead of working on the models, I am gleaning materials, first I have the stack of solid oak flooring rescued from the skip at work, they are refurbishing the toilet area, but where this came from I dont know.

next I have an old laser printer to strip down for gears shafts and other bits.

[Wildfuzz]

14 hours ago, grendel said:

I am gleaning materials, first I have the stack of solid oak flooring rescued from the skip at work, they are refurbishing the toilet area,

Rubber gloves me thinks!!!!

[ranworthbreeze]

Get on with the job, gloves bah!

You can wash your hands after going to the toilet

Regards

Alan

[grendel]

the strange bit is nobody can think where there was any wood flooring, it looks like offcuts from a new floor, but they have not laid any yet, maybe it was in the builders van?

[grendel]

I finished stripping the printer last night, so I have some nice straight steel shafts, and a whole bunch of gears, plus some stepper motors.

[grendel]

since I couldnt come to the meet, this weekend has been busy, apart from the delivery today and taking my parents shopping, this weekend, while awaiting parts to arrive to try a different coupling, I have spent the best part of two days clearing out the conservatories (we have 2 side by side, joined, one ebay purchase, one free to the person who took it down,) one is going to be my workshop.

I tidied half of the other last tuesday, and the other half yesterday, today (around the other tasks) I have made a big dent in the second one. still some bits to shuffle around, tomorrow I have about 4 car loads to take to the tip, and some more tidying, then perhaps I can start building the workshop.

[FairTmiddlin]

Peter 

Were these the kind of UJ's you were looking for

http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=282598256858

[grendel]

Those could do the job, but it depends upon the hole diameters in the end part, I need to go from a 2.3mm shaft to a 4mm shaft. I was planning to replace the plastic centre part on the ones I have with 6mm id silicon tubing (to fit on the 7mm splines of the metal parts of the coupling.

[grendel]

considering that this morning there was only an 18" path through here I think I am doing well at the moment, I have been looking at the table saw, ideally I would like it on casters, I had thought of mounting the vacuum under it, but then I realised I need to remove that occasionally to empty it

[grendel]

Well as I had bought some castors at lidls the other week, I felt ok about using the ones I bought the time before, 2 are locking ones so the saw wont run away from me, in the morning I will be adding a rim around the edge from some 1 1/2" x 1" timber I have lying around, this will stop the saw sliding on the base and falling off, without the need to permanently fix the saw to the base. the added bonus it brings the saw up to my level more.

[grendel]

This morning I have roughly framed in the top, a bit of scrap timber roughly hacked to size, glued and screwed.

[grendel]

so finally back from 4 tip runs and ready for breakfast, en route I picked up a sheet of 1/2" ply to make up one wall of the workshop (cover the glass on the side facing the fence / neighbours wall) this is to protect the glass from flying bits of wood etc and give me somewhere to mount the tool racks and storage bins.

[grendel]

well the plywood is protecting the glass, the furniture is rearranged - the two wall cabinets sitting one over the other will be moved and hung in the kitchen at some point, when this occurs the bench will be constructed along that wall.

everything is back in, more rearranging is going to be done, to allow more tools to be used in situ. but after a long weekend of hard work, I have the makings of a workshop, at the moment the only workbench I have is the fold down top of the ancient kitchen unit - this is probably as old as me, and has survived my parents home and moving with us since we have had a house

[Wildfuzz]

You and Timbo should get together for workshop planning. Matching pine units very posh, and warm through the winter months. A right little "Man Cave"

[grendel]

we got the wall units cheap (one of my wifes purchases), before finding out that they were about a foot longer than the wall she wanted them fixed to (across the back door), so they got relegated to the conservatory. they will be installed into the kitchen one day, but not on the wall originally proposed.

once I have figured how to get the flue of my woodburner through the roof, that may well get installed for winter warming.

[grendel]

well another evening last night with no modelling done (still awaiting some parts, and to be honest until I solve this coupling problem, I dont want to do anything drastic like fixing the prop shaft in place on model #2), get model 1 right first.

last night a short time was spent in the last corner of the workshop / conservatory, there is a bookcase here that I want to move out, then when that is done the wall units will go onto that wall for now, out of the way, anyway the serving trolley in front of the bookcase was tidied off and cleaned, and I then found my store of parquet flooring 4 big boxes full of it, all covered in pitch, so they would need to be cleaned up if I wanted to use them, I might put them to one side (again) in case I come up with a brilliant idea what to use them for each block is about 4" x 1" x 3/4" thick.

Anyway i digress, where was I - I have this theory, that when craftsmen are stuck on a project they resolve it by rebuilding and re laying out their workshop (well there is myself and Timbo as a great example of the theory).

the bookshelf coming out of the corner will be relocated along an outside wall, such that I can store power tools on its shelves, this just leaves a big wooden chest to relocate (at present its top hosts the band saw and small table saw). Once these issues are resolved i must build a work bench along the wall with the wood facing at the back, looks like another busy weekend ahead there.

then I will be looking at running power and lighting.

In the meantime hopefully the remainder of the bits will arrive and I can sort out model #1 and get her running quieter.

[ranworthbreeze]

Hello Peter,

Are these an option for the boats?

http://www.ebay.co.uk/itm/like/281980537995?chn=ps&dispItem=1&adgroupid=43677705735&rlsatarget=pla-325095017979&abcId=1128946&adtype=pla&merchantid=7220154&poi=&googleloc=1006964&device=c&campaignid=857250873&crdt=0

http://www.cornwallmodelboats.co.uk/acatalog/couplings-modular.html

Regards

Alan

[grendel]

I use the steel ones for meccano, they are good, but noisy at medium revs (1000 rpm) i would have to think how noisy they would get at 12,000 revs, plus they dont go to a small enough shaft size for the motors I am using.

The red couplings on the second page you linked, are what I have got at the moment, they are probably pushing it at 5000 rpm.

apart from getting the two shafts aligned as perfectly as I can, the only solution I have been able to find that will reliably perform is using the brass inserts from the red couplings, joined together with silicon pipe, which is the solution I am aiming for. I have also obtained some marine grease and syringes to inject it into the prop shaft, which should also quieten things down a fair bit. (not to mention reduce the chance of leakage through the prop shaft).

[grendel]

so this evening when I got home, there was the silicon tubing, I just had to try it for a fit, and I am happy with the result, I wont be fitting it until the marine grease for the prop shaft arrives, then I will do all the jobs at once. the motor will be fitted as near in line with the prop shaft as possible, then the grease will be syringed into the prop shaft, and the shaft refitted and the connectors fitted in while I am at it. so here are the old and the new

[VetChugger]

Nay Peter, surely you are not telling us that you have not made a minature stuffing box with a greaser that needs half a turn every day??

[grendel]

you mean like the 4th to 6th item on this page?

http://www.cornwallmodelboats.co.uk/acatalog/prop_shaft_accessories.html

Actually, from the look of those I could print one, but I am limited for space due to the batteries sitting above the prop shaft.