Topic: HMS Agincourt build project (Read 177431 times)

Geoff · « **Reply #175 on:** July 17, 2017, 01:46:29 pm »

For what its worth, my belief is the original auger was always intended to go in a Brace and Bit as the screw thread is designed to pull the auger down. If this is done in a pillar drill at any kind of speed it will put enormous strain on the auger and probably make the belt drive slip, which is what happened.

Machine augers tend to just have a triangular point to them as the downwards pressure is applied with the pillar drill handle. Candidly I have never liked using them as they always seem to be a bit brutal. Always have a sacrificial sheet both below and above the work piece if using a power auger as it stops splintering on initial cutting and breakthrough.

I have used circular saws to good effect (Barrel shaped) which work quite well if taken slowly and constantly backed off to clear the teeth.

Good luck

Geoff

Bob K · « **Reply #176 on:** July 17, 2017, 03:19:30 pm »

Geoff: I think you are right about the long auger, plus the fact someone else was drilling it. The Forstner bit had no problem, although it did get hot quickly at depth.

Warspite: I know you are trying to help, which is appreciated. The whole stack is well dowelled throughout. The new Forstner bit makes all the difference as it is so much more controllable. I am leaning as I go here.

Three Holes !

Lots of thought and careful planning. I finally have three holes bored nicely through eight layers of thick plywood. The Axminster DS2 drill stand proved a solid bit of kit, with a nice long drill travel. The Forstner bit also arrived today. The nearest size to 26mm was 1 & 1/16th inch, just under 27mm. So, a little bit of clearance for the one inch stainless tubes, hopefully not too much. Cut cleanly without any “snatch”, although as I went deeper I had to keep retracting it to clear the chippings. No worries with the workpiece clamped down it finally went through into the scrap board underneath. Edges of holes nice and clean, one advantage of boring it through as a set.

PHOTO:

Surprisingly, when I separated the stack and removed the temporary dowels, the tube sets seemed to go through more accurately than I’d dared imagine.

PHOTO:

Well, obviously I can't insert photos in any logical sequence in my text, using Mayhem attachments

SmugMug Problem

Major problem with SmugMug: It has cut me offer after trying to fill in my subscription with them, and each time refusing to recognise valid payment details. My Bank has now stopped my card, which is a major nuisance.
SmugMug have cut off access "as my 14 days trial has expired."

radiojoe · « **Reply #177 on:** July 17, 2017, 03:28:25 pm »

That all looks very satisfactory Bob, your patience has paid off.

Joe

Colin Bishop · « **Reply #178 on:** July 17, 2017, 03:37:18 pm »

Pleased to see you have had success at last Bob. Looking good.

Colin

ballastanksian · « **Reply #179 on:** July 17, 2017, 03:40:15 pm »

Great! That set up looks just right. Onwards and upwards

Bob K · « **Reply #180 on:** July 17, 2017, 06:21:15 pm »

A question for you experts out there. I intend to "tack" each bulkhead in position using an epoxy filler or putty. Should I use Plastic Padding or some other form of filler? Does it need to be waterproof as I will be using fibreglass resin and matting for the final bonding. This is just to hold it all in place, and make "cups" under the tubes/holes to fill with Z-Poxy 2 part resin.
I did see something mentioned elsewhere recently, but can't find it.

The interfacing pair between the hulls will need special care as alignment with the f/glass hull halves is important, and for the mechanical latch clamping later.

I will be doing a thorough clean of the fibreglass hull with warm slightly soapy water, then a light going over with a scouring pad to key the surface.

Colin Bishop · « **Reply #181 on:** July 17, 2017, 07:24:53 pm »

Plastic Padding and similar fillers are polyester based. Best to stick with epoxy I think.

Colin

Capt Podge · « **Reply #182 on:** July 17, 2017, 09:59:25 pm »

Quote from: Bob K on July 17, 2017, 03:19:30 pm

Well, obviously I can't insert photos in any logical sequence in my text, using Mayhem attachments

Hello Bob - It's great to see your patience beginning to pay off - now, with regard to the photos'

Have a look at "Seasprays" Scotia build log - you will see he does a sequential reference to his updates.

i.e. Pic 1 The three holes have been successfully drilled
Pic 2 Dry run of the stainless steel tubes
etc, etc...

...and the photographs are added at the end.

Not ideal for the way you like to run your build logs but better than nowt.

Regards,

Ray.

raflaunches · « **Reply #183 on:** July 17, 2017, 10:21:23 pm »

Hi Bob

Glad you got everything sorted and drilled as planned

Geoff · « **Reply #184 on:** July 18, 2017, 09:07:15 am »

Many years ago I needed to fit some solid ply bulkheads into a fibre glass hull and was told that if you just use fibreglass paste (with all the fibres in it) then there can be a tendency as it dries to pull the hull towards the bulkhead which can create a slight ripple on the outside. I gave a very thorough scoring to the inside of the hull. You really need to start exposing the strands to get a very good adhesion. Clean thoroughly. I fitted using epoxy glue and when dry ran a small fillet of car body filler round the edges and then overfilled with fibreglass paste - kind of finger curvature which spread about 1/2" up the bulkhead and about 1" to the hull. This gave an enormously strong connection with no rippling of the hull.

Cheers

Geoff

Bob K · « **Reply #185 on:** July 18, 2017, 09:47:09 am »

Geoff: That sounds great (and neat) for the final bonding of the ply bulkheads in the GRP hull sections.

However, what I need right now is something to "tack" them in place, like dobs of adhesive Plasticine.
I need to position the bulkheads quite accurately, especially the double thickness interfacing ones, bits of Duct tape would not be sufficient. With everything aligned in place I can then use the paste you suggested.

Colin Bishop · « **Reply #186 on:** July 18, 2017, 09:49:32 am »

How about blu tack?

Colin

Geoff · « **Reply #187 on:** July 18, 2017, 09:53:07 am »

I just used araldite. If you use the slow setting one you have plenty of time to position the bulkheads and fix them in position.

Cheers

Geoff

radiojoe · « **Reply #188 on:** July 18, 2017, 10:04:05 am »

Little blobs of Hot glue is the best I've found, holds instantly and strongly, If you haven't got a hot glue gun they are cheap and very handy for all kinds of temporary holding.

Joe

derekwarner · « **Reply #189 on:** July 18, 2017, 10:06:41 am »

All the talk of creating dams

........

Just select 1/8" section nitrile O-rings to suit the diameters required larger than the tubes....tack weld the O-rings to the hull sections with Super-Glu, then flood the cavity with the epoxy of choice

Naturally this process needs completion with the assembly structure such that the O-rings are laid in the horizontal plane, however provides a clean, robustly structurally sound and very tidy method of assembly of components with epoxy

Derek

Bob K · « **Reply #190 on:** July 18, 2017, 11:28:51 am »

Derek: That idea is pure genius

So simple, and effective. I would never have thought of O Rings.
20 on order

As for the dobs of Plasticine, I might try some standard red Milliput. It is just to initially "tack" the ply in position, later reinforcing with Araldite, then finishing with Epoxy paste as suggested

dreadnought72 · « **Reply #191 on:** July 18, 2017, 12:41:48 pm »

(Andy, looking closely at the work so far) If that ever snaps in two and sinks, I will personally dive it and rescue it. Wearing a tutu.

Bob K · « **Reply #192 on:** July 18, 2017, 01:25:25 pm »

It is probably over-engineered by a large factor, but as a first off I needed to be sure that each end could be supported in the air by the other half, fully loaded. Retrospectively, with the heavy gauge of the tubes, I could probably have got away with half inch and three eighths tubing. That is still a combined wall thickness of one eighth of an inch.

The main thing is - it will now fit in my tiny car

ballastanksian · « **Reply #193 on:** July 18, 2017, 08:30:09 pm »

The O ring idea is inspired genius

The Milliput should be quite strong as it does seem to stick quite well enough and should for the time it is holding your tubes in place.

It holds to smooth steel plate well though with enough force or a lever, it will pop off.

Bob K · « **Reply #194 on:** July 18, 2017, 09:35:04 pm »

Derek's O ring idea simplifies things a lot. Thank you Derek.

A slight pause whilst I cut out two casement "shelves" in the bow. Just noticed, in time. (see photo of Ron K's prototype)

At the moment the bulkheads tend to shift slightly with the slightest movement, the tube holes are so good an alignment, with approx. 1/16" clearance.

I need to slide the O rings onto the tubes first. A few small areas of Milliput will hold each bulkhead in position before Araditing to secure. When fully set I can stand the hull halves on end to Epoxy the tubes in, thanks to the O rings.
Lastly finishing off with fillets of Isopon P40 filler paste. The now redundant dowel holes can be filled with P40.

I now feel much more confident of this build reaching fruition. Thanks for all the helpful input.

I need to start thinking ahead to source four suitable Bueller motors, buy the Raboesch prop shafts, four 40mm brass props, and work out how I am going to pump 10kg of ballast water, both in and out. I am aiming for a "dry" lift weight of no more than 19kg.

"Onwards and upwards", as Ian said earlier.

ballastanksian · « **Reply #195 on:** July 18, 2017, 09:43:37 pm »

Power requirement versus flow rate I reckon. There have been discussions on here before now possibly on your Poly build when you were developing your internal systems, so maybe there are a few suggestions then not applicable that will now suit your much much larger hull!

You don't want to spend ages pumping ballast in and out, but you also do not want to flatten your main battery before you get to sail. Perhaps having the pump battery ashore and have leads running to the pump via a two way switch? You could thread the leads around a tether to keep her by the pond edge while you pump and not have leads and cable all over the place being a trip hazard etc

Hide the lead connector under a piece of deck furniture or in the superstructure.

derekwarner · « **Reply #196 on:** July 18, 2017, 10:18:34 pm »

Without going too far off thread.....the o-ring's can be used for the ellipicital intersection of propeller shaft tubes & the hull

Just gently squeeze an adequately oversized the o-ring to an ellipse...a few [4] welds of super glue then level the hull until the o-ring is in the horizontal plane & fill with liquid epoxy.....ten repeat on the other shaft intersections

Rudder posts is another prime candidate for a tidy and structurally sound mounting..........

If you swirl the O-rings in talcum powder prior to installation, they can be snipped away after the epoxy has dried

Derek

Geoff · « **Reply #197 on:** July 19, 2017, 08:26:40 am »

If you are planning on water ballast, I think I would just use a hand pump because the capacity can be what you want and no power consumption issues.

Cheers

Geoff

Bob K · « **Reply #198 on:** July 19, 2017, 08:55:18 am »

To reiterate, there are some practical limitations involved. Due to dodgy back and legs I am unable to kneel lakeside (I could never get up again). The system must take this into account.

Secondly, the overall "dry" lifting weight should not exceed 19kg. That is approx. double my HMS Polyphemus. I could manage that - Just. The overall ballasted weight is 29kg, of which 10kg to be pumped water.

I recall from my draughting work for MOD equipment that anything over 22kg has to have a red warning plate stating the weight. ie Electronic modules, equipment carry cases etc. One man lift limit.

So, internal self contained pumping system. I do not envisage current drain being that much for a short period.
If I run out of Rx channels a second Tx or key fob device. The volume between two bulkheads, up to the water line is approx. 4.5L ie 4.5Kg. One fore and one aft. Float switches as cut-offs. Lots of baffle plates to reduce swirling.
Bulkheads sealed, plus ballast tank top plate, also sealed in.

Can I do it with one bidirectional pump (reversible)? or will two pumps be needed?

Just some initial thoughts.

Bob K · « **Reply #199 on:** July 22, 2017, 10:26:36 am »

Some more progress to report. Both hull halves have been thoroughly cleaned and lightly abraded in preparation for mounting the bulkheads and tubes.

Before epoxying them in I decided to add some pairs of 27mm holes for wiring, and fettled the forwardmost bulkhead for the inset casement shelves.

I next needed to consider mounting the heavy duty adjustable toggle latch. This has to operate in a straight line, an inch above the waterline, so some re-think was required in how it operated. The fixed “catch” has to pass through two double bulkheads so I opted for a 3/8 inch square brass bar. An angled notch at the latch end, and a ¼ inch brass rod drilled through as a load bearer at the fixed end. The later will be reinforced with epoxy.

I am thinking of using a large O ring embedded in the join face to limit water ingress, plus building a deep box around the latch as safety backup.

The square holes will be corner drilled and chiselled out. Seating groove for the O ring calls for a ball end bit on my Rotacraft. After finishing this will be fixed with adhesive.

Materials for the above all on order. All cutting and drilling must be done before final fixing-in of bulkheads.

News:

Author Topic: HMS Agincourt build project (Read 177431 times)