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Decent half inch drill bit?
jps - 4/12/18 at 01:19 PM

What brands / supplier should i be looking at? I am thinking I will drill out my shock brackets to 1/2inch (they are currently around 12.3-12.5mm).

Ebay offers up 1/2inch drill bits from £1.50 - I don't suppose that's the level of quality I want though?!


rusty nuts - 4/12/18 at 01:47 PM

1/2" reamer?


jps - 4/12/18 at 02:05 PM

quote:
Originally posted by rusty nuts
1/2" reamer?


I have no idea what the difference is/how a reamer is used!

I will have to enlarge the holes on the car - if that makes a difference...


Bluemoon - 4/12/18 at 02:14 PM

Good ones are not cheap...

Dormer HSS..

Presto.


Learn how to re-sharpen them..

Before you drill them out are you sure 12.5mm is not big enough, at a guess 1/2 bolts are smaller than 1/2??

The above comments about a reamer is a good one as you already have a small hole, and would be easier to get a good finish.

[Edited on 4/12/18 by Bluemoon]


jps - 4/12/18 at 02:31 PM

quote:
Originally posted by Bluemoon
Good ones are not cheap...

Dormer HSS..

Presto.


Learn how to re-sharpen them..

Before you drill them out are you sure 12.5mm is not big enough, at a guess 1/2 bolts are smaller than 1/2??

The above comments about a reamer is a good one as you already have a small hole, and would be easier to get a good finish.

[Edited on 4/12/18 by Bluemoon]


I would think so too - but have not yet got my hands on a 1/2 inch bolt to try!


MikeRJ - 4/12/18 at 02:51 PM

quote:
Originally posted by Bluemoon
Before you drill them out are you sure 12.5mm is not big enough, at a guess 1/2 bolts are smaller than 1/2??



The shoulder of 1/2 inch bolt should be very close to 1/2 inch diameter (12.7mm), plus you need some hole clearance on top of this. If a half inch bolt fitted through a 12.5mm hole then it would be completely scrap.


cliftyhanger - 4/12/18 at 02:57 PM

Re drill quality, I needed a 16mm drill on Saturday. Like then.
Off to toolstation, bought a "Toolpak" bleacksmiths drill. Seems to be fine, I was drilling 3mm thick box section to take crush tubes.
Probably won't last forever, but treat them with respect and they will do the job. Not sure I would use silverline or unbranded...


nick205 - 4/12/18 at 04:42 PM

Enlarging an existing hole in metal with a drill isn't easy on the drill bit, the bit can snatch and struggle.

Dormer and Presto mentioned above are brands I've used and trusted before in machine shops.

Also check that your drill chuck can accept drill bits that large. Many chucks will accept Ø13mm, but some willl only go to Ø10mm (particularly on cordless drills). If yours only accepts Ø10mm you can get "Blacksmiths" drill bits that have smaller diameter shanks for the larger diameter drill bits. Never used one myself so no idea of the quality of them though.








[Edited on 5/12/18 by nick205]


CosKev3 - 4/12/18 at 05:39 PM

12.8mm drill bit you want.

You might find you can't get your drill in to do the upper rear ones, I did mine couple of winters ago and I had to cut a drill bit down and weld a nut on the end and use a ratchet spanner on it to drill the holes out!


matt5964 - 4/12/18 at 09:35 PM

We do all the major brands and our own Sherlock brand is made by the first main brand mentioned in the thread 😸

https://www.cromwell.co.uk/shop/cutting-tools/jobber-drills/391505?query=drill%20bits


J666AYP - 4/12/18 at 11:32 PM

I would use a nice reamer to avoid churning up the bit or the hole wandering. Failing that a Decent HSS bit that was not made in china.

Jay


matt5964 - 5/12/18 at 07:44 AM

quote:
Originally posted by J666AYP
I would use a nice reamer to avoid churning up the bit or the hole wandering. Failing that a Decent HSS bit that was not made in china.

Jay


We do readers as well
https://www.cromwell.co.uk/shop?query=Reamer


joneh - 5/12/18 at 09:57 PM

I bought an old reamer off eBay for my chassis. I find the old stuff much better than the cheap pap from Toolstation / Screwfix and the like.


jps - 14/1/19 at 11:40 AM

Just to feedback to everyone (thanks for your comments here and on the anyone use RDG tools thread) - my hand reamer came in the post and made short work of clearing out the existing holes to a much closer 1/2 inch fit on the 1/2 inch bolts I have. Still a little play - but job done.