Which security chain?


It should arrive tomorrow. Serious question, does anyone have a workshop, a mains powered angle grinder and skills? I’d gladly sacrifice a link in the name of research. (Assuming I’ve enough length left to actually lock the bike).

I know the thieving element will be using a battery powered angle grinder but the purpose of the test is to see how long it takes to get through in ideal conditions.


Almax 19mm with a mains angle grinder

Pragmasis 19mm


Yes there’s no video for the 22mm one though. I could be first.


Horrible to see those videos.

They’re not grinder proof, and I don’t think anyone is claiming they are. At best they will deter, then hopefully slow down thieves who are willing to give it a go, which with luck will allow time for a response to be mounted. Given a dedicated enough thief, nothing will stop them :frowning:


Throwing some petrol over the little darlings may deter them from continuing!


Well it took over 13 minutes to grind the 22mm Almax and we destroyed 2 discs in the process. Video soon.

We ground an Oxford Boss chain too…under 2 minutes.


Looking forward to that video. What was the specification (manufacturer/model/size) of the angle grinder and discs?

Isn’t the Oxford Boss a little 12 mm bicycle chain?


Here are the specs. Yes the Oxford Boss is about 12mm. They sell it with an alarmed disk lock usually.

Makita DGA452Z 18 V Body Only Cordless Li-ion Angle Grinder https://www.amazon.co.uk/dp/B00ISWYHHO/ref=cm_sw_r_cp_apa_i_kf3xCb3B0Z34M


That’s a relevant test since its probably similar kit to what the average thief will have. Did you grip the link in a vice or do a ‘in real life’ test with the link man handled between boot and floor?

Maybe I should just wait for the video.


also available


We clamped it in a vice because we figured we wanted to find the fastest possible way though and then treat that as the minimum possible time. The results were pretty interesting. I’m just uploading the video now. Big thanks to Ricky for being the competent person in this outfit.



Like you say in the video, if technique is good it could be even quicker.


Wow! Gives me a bit of confidence in my bike still being outside when I leave work!
Great work guys!


Impressive resistance. Sure a better technique, lubrication and control would definitely achieve a faster cut time. I’ve seen 19mm Almax chains defeated in less than 2 minutes but this was with far more powerful 240v tools. However, an under 18 up and coming footballer would struggle to achieve anywhere near your timings on his hands and knees in the gutter.


im not surprised it took so long the link is for a grinding dics not a cutting disc
cutting discs are 1mm - 2.5mm & yes it makes a massive difference


Oh, how long do you think it would take with a cutting disc? I effectively have a disposable link now so I can look at doing another test.

EDIT: Aw hell. I put the wrong bloody link and screen shot in the video. I actually used these.

Looks like I’ll have to pull the video and re upload it tonight.


Praise to Screwfix Hight Street Kensington for selling me the right disc.


cant beat screw fix
its interesting because i had to cut my 19mm Almax i lost the keys to the lock
i used a dewalt angle grinder & a 1mm disc took me 90 seconds


If you want to have a go with my disposable 22mm link you are more than welcome. It would be interesting to do a comparison.