PROBLEM, HOW TO - open up an inaccessible hole in 10mm s/s?

Rather than open the hole can you bush the fitting down to 9mm, then use a higher quality pin, if size is critical, to compensate?
Tapered reamer won't work, you'll want a parallel sided hole.
A right angle chuck attachment might just get in, with a good quality drill bit you have shortened and reprofiled.
I would make an adaptor as above, but from 10mm steel and bolt on one side, or a fork bolted through.
 
Amulet said:
Maybe you have more patience than me. I think it's a near impossible job to file the hole in plate that thick a millimeter larger even with decent access.

Unless the stay is already made to length, I'd put another link in the system - a long shackle or a custom made pair of plates bolted through the existing hole to give you an attachment point above the bow fitting. bit of a bodge, but I think it could be done fairly neatly and with little loss of strength. If that can't be done then I think your best bet is to replace the pin with a bolt that fits through the existing hole.
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The best suggestion yet
 
Why go to all that trouble of trying to drill it out , why not buy one of these http://hayn.com/marine/rigging/tj.html - Eye - Jaw Toggle. TOG05 . You could always drill the 3/8" one out to 10mm to accommodate your new stay if needed with a pillar drill ?

If neither are suitable because of the length between pins, you could make one relatively easy with a grinder and a pillar drill and some S/S bar.

Only a thought Philip


"Second item down on the page on the web site."
 
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If you do go down the hand filing method I'd be interested to hear how you get on. I'm not without experience in such tasks and I'd rate it as hopeless. A millimeter is a LOT, not a little bit to remove from 10mm thick stainless steel. However people with more experience than me recommend it so I could be wrong.

If the only option is to widen the hole, I actually think this is going to be a horrid job however you do it.

Would this right angled chuck fit? http://www.amazon.co.uk/dp/B0024LR4ZW
I'd try to find some way of getting a power tool in there if I had to do the job.
Smaller right angle attachments for screwdrivers like this are available: http://www.amazon.co.uk/dp/B000T9QXF8
You might find a way of attaching a grinding tool to one.

It is a judgement call whether to use a smaller pin. I wouldn't get all hung up on it invalidating insurance and warranty etc. It's true that if it does break and that results in an insurance claim, and the insurance company look carefully enough, your claim might fail. If I judged there to be any real chance that it would fail in a way that was dangerous or expensive I wouldn't do it, and actually my boat, and most others, are full of major and minor judgement calls of that sort. Amulet surveys OK, and I get insurance easily.

p.s. Fisherman makes a good point about a parallel sided hole above. Reaming out the hole, unless done perfectly is also going to weaken the setup. The the entire strain could end up on a particular high spot in your filing out, whereas a smaller pin would at least spread the load along its length.
 
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I assume that you are doing this on the boat, Is it possible to remove the whole fitting and then drill right through? or cut two cheecks and get them welded in suitu, predrilled of course. Best of luck
 
I think if your pin size is critical and an attempt to expand the hole is messy, this could result in abnormal stress on the pin, with failure risk. However, the fitting in #23 has a swivel which might be an improvement on having the stay jaws attached direct to the plate. Also, it could be bolted, which may? be stronger than a pin, rigid fixing= no wear.
 
Amulet said:
...........I'm not without experience in such tasks and I'd rate it as hopeless. A millimeter is a LOT, not a little bit to remove from 10mm thick stainless steel................
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A lot depends on the grade of inox: If its armour plating or security chain, roofing bolts, knife blades........etc Then you are immediately on a hiding to nothing. In this case the plate was cut, drilled and welded during fabrication, (as oppose to forging and grinding,) so it should not be that hard to work with.

Another thing to note is that the smoothness, (teeth per inch) for the file or saw has a large bearing on how easy the work will be. Ideally you want a smooth file in very good condition, nearly new condition. Counter-intuitively, a brand new file is probably not quite as good as one that has been lightly used, (though brand new is better than a file that is badly worn.)

If you are tempted to go the filing route, try testing the file on an easily accessible edge of the plate to see if it bites. If everything is okay, then work at a nice steady pace.

Someone suggested that enlarging the hole would affect the shear strength of the pin. It might, but if it's done carefully then it should be no worse than what you would have through normal wear and tear.

Also, I am being pedantic, but it is actually only half a millimetre per side and this will make a slight difference.

Edit

In addition, I genuinely believe that any attempt to drill this hole out will quickly turn into a nightmare. I don't think you will be able to get drill speeds that are sufficiently slow and, in addition, you will find the drill snatching, sticking and breaking. Though I could be wrong.
 
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xeitosaphil said:
Why go to all that trouble of trying to drill it out , why not buy one of these http://hayn.com/marine/rigging/tj.html - Eye - Jaw Toggle. TOG05 . You could always drill the 3/8" one out to 10mm to accommodate your new stay if needed with a pillar drill ?

If neither are suitable because of the length between pins, you could make one relatively easy with a grinder and a pillar drill and some S/S bar

+1 S/S bar thats the way to go but forget diy I would see your local engineering shop use around 25mm bar by possibly 100mm mill out a slot to fit your centre plate with 9mm hole and suitable tenon with 10mm hole also chamfer all edges.Fit with rigging pin. You may find a suitable bar extension at a rig shop but it is a long shot.
http://www.s3i.co.uk/bartoggle.php Similar to this

Cheaper still is to use two chunky links of solid bar say 6mm x 25mmx 100mm fit spacer between top holes.
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To drill SS you need a Cobalt bit, normal metal drills won't do anything. Given how wide the hole is and how small the gap is you would have to cut down both ends of the bit and sharpen the drill end to fit the hole.
 
KellysEye said:
To drill SS you need a Cobalt bit, normal metal drills won't do anything. Given how wide the hole is and how small the gap is you would have to cut down both ends of the bit and sharpen the drill end to fit the hole.
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Ah, modern technology!

At the end of the day, drill speed and feed pressure are more important than exotic materials. Sure they, (cobalt drill bits,) may help, but they can also be more problematic than traditional HSS. They are certainly way more expensive.

Take a look here at this guide by the "British Stainless Steel Association" to see how it is done.

http://www.bssa.org.uk/topics.php?article=194
 
There seem to be some strange and exotic stainless steels under discussion in the thread. I would be most surprised if fitting of this type was made from anything other than 316, or 304 in a budget boat. The hardness of 300 series stainless steels is low, about the same as mild steel, but it work hardens rapidly, particularly if blunt drills are used. Note that work hardening by definition requires plastic deformation, so filing, hacksawing, reaming, etc does not cause it. The reason that cobalt drills work so well is that they keep their edge far better than HSS drills and so minimise plastic deformation.

I have drilled out holes in stainless steel like those under discussion countless times but the difficult access here makes the required high feed force difficult to achieve. Unless the bowsprit can be removed without too much trouble to enable a direct feed with a hand drill I think I would go along with many other suggestions and ream or file. I did think that tapping a thread first was an excellent idea, removing about half of the metal with minimal effort.
 
Irvine_himself said:
Think very carefully before using a smaller pin, even if it worked, (and that is a big if,) it would invalidate any warranty and probably cause insurance problems.
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Struggling to see the circumstances that a 9mm pin in the correct-sized hole will lead an insurance assessor reject a claim. Or even what claim would be made for what is, in effect, a secondary forestay.
 
Lakesailor said:
Struggling to see the circumstances that a 9mm pin in the correct-sized hole will lead an insurance assessor reject a claim. Or even what claim would be made for what is, in effect, a secondary forestay.
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It is not difficult to imagine accident scenarios involving a forestay snapping while under tension. For example crew being knocked overboard or seriously injured, by a flapping stay sail.

Sods law dictates that if the pin does fail, it will do so at the most inconvenient time possible and result in a cascade effect with any number of undesirable consequences up-to collision and/or death.
 
If the inner snaps I assume the main forestay must have already gone, which would be a major warning.

You're not an HSE Officer are you?
 
lw395 said:
My first idea is quite bodgy:
Find a selection of old taps (the thread cutting sort!) and wind in anything less than or up to 10mm that removes metal.
If you have a random selection of BSF, metric and so forth, you might loses most of the unwanted metal.
Finish with a file, possibly one you've ground some teeth off so as not to cut where you don't want to...
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Not dodgy at all. Excellent idea imho - the best on this thread. The tap can be turned easily using a ratchet spanner. One M10 tap will remove half the metal, and playing around with near-sizes, or better still an M10 "fine" tap, might remove all or nearly all the rest. Then finish off with a file as you say, or one 10.1 reamer
 
Lakesailor said:
If the inner snaps I assume the main forestay must have already gone, which would be a major warning.

You're not an HSE Officer are you?
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Not necessarily true if the inner forestay has been seriously weakened by the use of an incorrectly fitted pin.

After a few years as journeyman, I went off to Uni to avoid having to file holes in SS. Subsequently I worked as an R&D Engineer, vainly believing I could thus avoid H&E. When I dropped out to become a dog handler, I still found myself being assigned as the designated Safety officer.
 
KellysEye said:
To drill SS you need a Cobalt bit, normal metal drills won't do anything. Given how wide the hole is and how small the gap is you would have to cut down both ends of the bit and sharpen the drill end to fit the hole.
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Not true.

I have worked with stainless in various grades for years.

Use normal engineering H/S bits, nicely sharp, slow speed, lube, HIGH PRESSURE-if the bit skids it work hardens the surface, stopping further cutting.

In my experience, its the speed and pressure that are important.

I would use the existing hole-the inner forestay is unlikely to require a 10mm pin or bolt, although its nice to have.

I foresee problems unless the bow roller is removed and dealt with in a workshop.
 
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