Rich too Posted October 5, 2015 Share Posted October 5, 2015 My next project will have a DLE 30 and this will be the first engine I have bought which has the multi bolt hub. I don't really fancy drilling the props for it, and I know there are options of a single bolt adapter - which involves modifying a new engine, or buying pre-drilled props. I am tempted by pre-drilled props, are there any UK suppliers though? What do you guys do? Edited By Rich2 on 05/10/2015 11:15:31 Quote Link to comment Share on other sites More sharing options...
iqon Posted October 5, 2015 Share Posted October 5, 2015 I used the supplied prop washer and a pillar drill, you can buy a jig from ebay Quote Link to comment Share on other sites More sharing options...
Geoff S Posted October 5, 2015 Share Posted October 5, 2015 I have a Mackay 30cc petrol engine which has multibolt prop fixing. I drill the props and attach them with HT cap head bolts which seems to be the proper thing to do. I do find it a bit of a bind and much less convenient than the single bolt fixing that my Zenoah 26 uses. Neither has ever come off. Until that recent report in the BMFA mag, I assumed the multi-bolt method was more rather than less secure. Perhaps it is. I've had glow engine props come off on 4 strokes when they kick back though not at high speed, fortunately and usually when starting. Have there been occasions when singe bolt mounted props have caused serious injuries as aseems to have happened in the reported incident? Geoff PS I also use the prop washer as a guide and use my pillar drill. Edited By Geoff Sleath on 05/10/2015 11:25:19 Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 5, 2015 Share Posted October 5, 2015 Not had one of either sort come loose myself, I borrow a jig off one of lads for multi bolt types, then ask him to drill it for me on a pillar drill it's easy to get it slightly wrong on each hole when doing with a hand held drill, then you might bend the bolts when tightening up, I use biggest washer I can on the bolts so it doesn't crush the prop, and I thread lock them as well. John Quote Link to comment Share on other sites More sharing options...
ceejay Posted October 5, 2015 Share Posted October 5, 2015 I am fortunate to be able to make my own jigs for such things, and I would indeed recommend using a jig, as has been said just using the prop washer could lead to out of alignment as you go through due to the drill wandering off line if its not supported square, a 5mm thick prop washer could allow it to wander as the holes on washer will be a clearance on the drill of a few tenths of a mm and even a small amount out on all 4 or indeed 6 holes will cause all sorts of problems, if you cant screw the bolts in through the washer/prop and into the driver with minimal effort with fingers then its out of alignment somewhere, always use a pillar/bench drill or attachment to your trusty b and d again to keep it all nice and square, also I don't understand the need for large washers under your bolts john as surely there is already a prop washer twixt bolt and prop to give even pressure across the prop boss, one of these might be a good investment if your really keen on keeping it all nice and even, **LINK** cj Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 5, 2015 Share Posted October 5, 2015 Yep you're right there CJ, bit of brain fade on my part John Quote Link to comment Share on other sites More sharing options...
ceejay Posted October 5, 2015 Share Posted October 5, 2015 i know what you mean, mine fades more as i near 60, it will be all monochrome soon!!! cj Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted October 5, 2015 Share Posted October 5, 2015 Posted by ceejay on 05/10/2015 17:46:59: i know what you mean, mine fades more as i near 60, it will be all monochrome soon!!! cj Don't think it's my age C.J...I blame the diesel fumes John Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted October 5, 2015 Share Posted October 5, 2015 I've never used a multi-bolt fixing but I do recall reading some advice somewhere about the orientation of the holes - i.e. . o o o . o o . == o + o == OR == + == . o o . o o o ...which I assume is to do with grain orientation / strength...anyone know which is correct? Edited By Martin Harris on 05/10/2015 19:25:00 Quote Link to comment Share on other sites More sharing options...
Rich too Posted October 5, 2015 Author Share Posted October 5, 2015 Thanks guys, I inherited a pillar drill from my dad, and I have never used it - no excuse then! I guess you have to drill the centre hole too? As they are usually 8mm and the DLE shaft is 10mm? Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted October 5, 2015 Share Posted October 5, 2015 I use multi bolt props for my DLE55RA. I use a drill jig and pillar drill and have never had a problem. Positioning of the holes is important if you plan on hand starting, to make sure the prop is at quarter past nine position (or ten past eight position if you prefer) when turned up to the compression position. Just needs a bit of forward planning of the hole positions before you drill. Not sure whether pre-drilled props will take this into account. The prop washer that goes on after the prop has 4 bolt holes plus the centre hole, so the bolt washers aren't pushing directly against the prop. Quote Link to comment Share on other sites More sharing options...
Rich too Posted October 5, 2015 Author Share Posted October 5, 2015 Yes, I hand start mine. The one place (in the US) I found that pre-drills them in one of two positions depending on preference. Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted October 5, 2015 Share Posted October 5, 2015 Posted by Martin Harris on 05/10/2015 19:09:13: I've never used a multi-bolt fixing but I do recall reading some advice somewhere about the orientation of the holes - i.e. . o o o . o o . == o + o == OR == + == . o o . o o o ...which I assume is to do with grain orientation / strength...anyone know which is correct? Edited By Martin Harris on 05/10/2015 19:25:00 I can see what your ascii art is now that you've finished it. Hole orientation is just for the prop position for hand starting. Quote Link to comment Share on other sites More sharing options...
iqon Posted October 5, 2015 Share Posted October 5, 2015 dont forget depending on what spinner you use that will want drilling as well in line with prop Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted October 5, 2015 Share Posted October 5, 2015 Posted by Gary Manuel on 05/10/2015 19:46:26: I can see what your ascii art is now that you've finished it. Hole orientation is just for the prop position for hand starting. I'm only going by memory from something I read years ago in passing but it seemed to suggest it was for strength reasons. Looking at pictures of full sized props, they al seem to be oriented as per the first example - perhaps it reduces the chances of cracking across the grain with the longer lateral distance (I assume the grains of the planks are oriented generally parallel unless they make full sized props out of very fat trees!)... I hope we find out the cause of the reported incident without delay - I do a lot of noise tests at our club! Quote Link to comment Share on other sites More sharing options...
Steve Balaam Posted October 5, 2015 Share Posted October 5, 2015 I'm not a big fan of multibolt fitting so have modified my DLE30 with one of these, not yet tested yet though **LINK** Steve B Quote Link to comment Share on other sites More sharing options...
Rich too Posted October 5, 2015 Author Share Posted October 5, 2015 Tempting, but I don't like the idea of hacking a new motor! Quote Link to comment Share on other sites More sharing options...
Rich too Posted September 7, 2016 Author Share Posted September 7, 2016 I have the equipment needed including a pillar drill. Question is, how do I drill the prop out to 10mm to start with? I have to make sure to drill dead centre and I have no way to hold the prop. Thanks Quote Link to comment Share on other sites More sharing options...
Nigel R Posted September 7, 2016 Share Posted September 7, 2016 I'd use one of these for the 8mm -> 10mm opertation: http://www.ebay.co.uk/itm/RC-6-7-8-10mm-4-Step-Metric-Prop-Reamer-RT646-/322054871262?hash=item4afbf758de:g:aBwAAOxyXDhSoFXB The existing 8mm hole will keep it nicely lined up while it cuts the 10mm hole. Edited By SuperNash on 07/09/2016 15:10:23 Quote Link to comment Share on other sites More sharing options...
Rich too Posted September 7, 2016 Author Share Posted September 7, 2016 Perfect and it fits in a drill press. I searched for stepped drills! Thanks Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted September 8, 2016 Share Posted September 8, 2016 I use one of these Quote Link to comment Share on other sites More sharing options...
onetenor Posted September 8, 2016 Share Posted September 8, 2016 Find step drills on Bang Good site. Excellent quality and value Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted September 8, 2016 Share Posted September 8, 2016 Flying my Seagull Edge on a RCG 30 it suddenly stopped moving forwards very much and would not respond to throttle, also a large object was seen to fall off. On landing the prop. and spinner were missing. All four M4 bolts had sheared. When the remains had been dug out of the prop. driver the bolts were replaced with proper high tensile ones. Something to think about if you have Chinese bolts. Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 8, 2016 Share Posted September 8, 2016 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Rich too Posted September 10, 2016 Author Share Posted September 10, 2016 I've finally done it. Not without a bit of messing about, and I would not attempt it without a pillar drill. I had a problem in that when I used the ream to drill the centre hole out to 10mm, the prop still would not fit on the crank. Obviously some definitions of 10mm differ to others! So I had to use a 10mm drill to finish the job off. Quote Link to comment Share on other sites More sharing options...
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