My 2010 Kona Jake the Snake has two threaded mounts for both rack and mudguard on each side of the rear dropouts. After the frame cracked and a warranty claim, Kona have supplied a replacement frame but it's the 2012 frame which has only one threaded mount on each or the the rear dropouts, so I can't easily mount both a rear mudguard and a rear rack on the 2012 frame.

This is quite surprising: surely the reason for updating a frame is to make it better, not (even slightly) worse? Kona say the Jake the Snake makes a great commuter bike. For me, choosing between having a rack or mudguards isn't an option - I need both, just as I had on my 2010 Jake the Snake, which is a great commuter and all-round bike! Anyway...

The screws supplied with the rack and mudguards don't allow them to be fitted on the single rear-dropout mounting holes at the same time.

Is there any easy way I can fit both the mudguards and rack onto the 2012 frame? I could use longer screws if I can find the exact correct length but that's proving to be a problem here in the UK and also, would it be safe to fit both items using one mounting point?

I am curious as to why Kona have only provided one mounting hole on the latest frames whereas the 2010 frame had two?

It is perfectly safe to mount rack and mudguards onto one eyelet. My commuter bike is like this, I have hauled heavy shopping and used the bike for many years.
Fit a long stainless steel allen bole of the correct length. I prefer mine to protrude about 1-2 threads. Fit the rack first then the mudguard stay then a washer. You can add a star anti-rotation washer if you want.
Any bikeshop or hardware shop should have the correct allen bolt.

Or, you can get a small bag of bolts on Amazon. Also, you always use a dab of Locktite 242 on the threads. It provides a good hold on threads, but allows one to unscrew it later. (I.e. - it is not permanent)

Just look around your bike stuff drawer and you may even have the right length screws/bolts. Maybe even the ones from your water bottle holes on the frame?

As mentioned above, make sure the rack goes on first, otherwise you will bend the screws.

I'd use the eyelets for the rack mounting, and then a set of P-clips for the fender mounts.

The JTS is designed as a jack-of-all-trades, and one of those trades is CX racing. It's rare you'll see anyone racing with fenders or a rack. It does many things "OK" but none of them perfectly. The new model is a bit more geared toward racing than the 2010 model, but overall it has never been strictly a commuter bike.

I've got a 2011 RL Conquest Pro which is a similar bike; Alu/CF, and it too has only a single eyeletted rear.

p clips are versatile and some racks come with them as an option. my current rack did (white Botecchia has no that right no eyelets!) (no close up availabe) the other pics show a front rack that I used for a while and also the top mounting of a rack using the clips. I like the idea of separate connections in case adjustments or changes are desired.

Ace Hardware is my source for M5 and M6 bolts. The local store carries a nice variety of lengths and suitable washers in stainless steel. I think they carry nuts for them, as well, but I can't swear to it.

I get mine at Ace too, but I don't like the finish on them. They're ugly.

Anyone have a source for M4/5/6 bolts with a decent finish?

The OP is in the UK, so not sure Ace is the place for him... but it is for me .

I run a rack and fenders on the same eyelet at the drop out. Finding frames with double eyelets (in my price range, anyway) is a very time consuming process these days.

The Home Depot I work at PT has them in black I think up to 40mm or even 50mm in length. I don't work isle 18 but was there the other night helping a guy similar bolts. I think he wanted M6 but long like 30mm or 40mm and I remember seeing other sizes and longer ones too.

You don't need to find a a bolt that fits exactly. Just get one that's too long and you can cut it to the proper length in 10 seconds with a hacksaw.

The local Ace here carries at least three different finishes. I like the stainless steel version

My local Ace used to have smooth stainless head bolts -- not particularly shiny, but not ugly. I haven't seen them in a couple of years. Now it's either black (which isn't too awful) and the silver ones with ribs around the head (which I guess might also be stainless).

Ha! You're assuming I have a bike stuff drawer?

I dont like the idea of using P clips when you have perfectly usable threaded eyelets. Once setup, you never need to adjust rack and fender. P clips are an ugly hack to be used only where neccessary and they are another nook and cranny where dirt gathers.

To cut a bolt you need a bench vice and a hacksaw and metal file , or a dremel. You have to finish a hacksaw cut with a file to clean up the threads. Always cut on the long side.
Long protruding bolts may interfere with the chain in the smallest sprocket so file back where needed.

Thanks to everyone for your help and advice.

I don't have a bench or many tools for that matter so I'll probably end up getting my LBS to fit the rack and mudguards.

If you don't have a bike stuff drawer, box, bin, cabinet, paper bag, or whatever - then you need more bike stuff!

re: "I'll probably end up getting my LBS to fit the rack and mudguards."

no shame in that, in fact now we're all jealous!