SOHC.co.uk Forums > Anorak's Corner

Drill recommendations

(1/3) > >>

paulbaker1954:
Can anyone recommend a set of drill bits for drilling out old Honda panhead screws and the like

I seem to continually struggle with what I thought was a simple job. My Bosch HSS bits don’t seem to touch them

I also bought a set of cobalt ones but struggle with those as well

Maybe I need a class in the art of drilling 😂😂😂

matthewmosse:
I just use Lidl  /  parkside drillbits most of the time, if they snap I top us using cheap drills off Ebay, I think it was about £9 for 99 drillbits, lots of the small sizes, less as you go up. I was using one of these cheapie to centre bore stel bar on the lathe, managed about 1.5 metres in total before sharpening was needed. I often find drills are not properly sharp when new and need a tickle, and the wings also chip easily on rounded Phillip's screws until they are properly eaten into by the drillbit, I go for a 7 or 8mm drillbit to start off taking the heads off m6 panhead or Allen screws if they round. If a good lot of swarf isn't spoiling off the drillbit, stop and sharpen, never persist as a drillbit, once it's got hot needs s lot of effort to sharpen and get back to properly tempered steel that will hold an edge. My pet hate is blunt drillbits, spent 18 months in an engineering firm where no one sharpened drillbits and the pedestal grinder was miles from the drill, I have bench grinders 2 foot from the pillar drill, running several grits of stone right down to a really fine, water cooled whitestone. A shap drillbit should have the head off a m6 panhead in 30 seconds, using a basic cordless drill.
After practice I now tend to be able to fairly consistently drill bolts out well enough to pull the thread if the bolt out like a helicoil gone wrong leaving the trapped hole intact.

paulbaker1954:

--- Quote from: matthewmosse on October 11, 2019, 12:21:38 AM ---I just use Lidl  /  parkside drillbits most of the time, if they snap I top us using cheap drills off Ebay, I think it was about £9 for 99 drillbits, lots of the small sizes, less as you go up. I was using one of these cheapie to centre bore stel bar on the lathe, managed about 1.5 metres in total before sharpening was needed. I often find drills are not properly sharp when new and need a tickle, and the wings also chip easily on rounded Phillip's screws until they are properly eaten into by the drillbit, I go for a 7 or 8mm drillbit to start off taking the heads off m6 panhead or Allen screws if they round. If a good lot of swarf isn't spoiling off the drillbit, stop and sharpen, never persist as a drillbit, once it's got hot needs s lot of effort to sharpen and get back to properly tempered steel that will hold an edge. My pet hate is blunt drillbits, spent 18 months in an engineering firm where no one sharpened drillbits and the pedestal grinder was miles from the drill, I have bench grinders 2 foot from the pillar drill, running several grits of stone right down to a really fine, water cooled whitestone. A shap drillbit should have the head off a m6 panhead in 30 seconds, using a basic cordless drill.
After practice I now tend to be able to fairly consistently drill bolts out well enough to pull the thread if the bolt out like a helicoil gone wrong leaving the trapped hole intact.

--- End quote ---

Thanks Matthew I think I must just be doing something fundamentally wrong with my drills or something. I even tried to drill out some cheap screws from my gate hinges last weekend and just could not get the drill to bite. Sadly I have never been trained to sharpen drills and don’t have a grinder in my garage so I Just buy new drills but simply can’t understand what I am doing wrong

For example I tried drilling off the pan heads on my oil pump and got nowhere even with Cobalt drills🙈🙈🙈

AshimotoK0:
I drill a fairly small hole and hammer in a Torqx type bit or use a 5/16" bi-hex socket onto the outside of those screws. Will have to check but pretty certain its a 5/16" or you can use one of those sockets with internal Torx type profile. The impact and superior  grip almost always gets em out. The exception are the ones that the thread had severely corroded in the alloy and the thread snaps off with the excessive torque applied. If using a socket best to grind off the front chamfered portion  to get more of the profile forced onto the pan-head.

davefirestorm:
As stated make sure the drill is sharp and don’t run drill too fast put a smaller hole in first and the bigger drill will follow that hole a centre drill ideal to use initially

Navigation

[0] Message Index

[#] Next page