1737 forum posts
what are they made from (main drill body) and can they be ground for steel?
|Michael Gilligan||02/06/2015 21:57:08|
16648 forum posts
what are they made from (main drill body) ? ... Non-descript steel [approximating Cheese]
can they be ground for steel? ... Geometry, Yes ... Durable edge, No
3960 forum posts
I've ground the carbide tip for doing stainless steel.
The main body appeared to be ordinary steel on my cheapo masonry drills
Drilled it using the backgear, less heat
|John Haine||02/06/2015 22:01:09|
|3428 forum posts|
The tip is tungsten carbide and can be ground to a sort of point for steel I understand. I think some sort of 4 facet grind would work. I can't remember where I saw this but could be useful if you have something too hard for a normal drill.
|Michael Gilligan||02/06/2015 22:03:26|
16648 forum posts
|David Colwill||02/06/2015 22:06:14|
|679 forum posts|
The body of the drill varies according to quality, the better ones are made from a tough steel and the cheap ones from cream cheese. I have used this dodge on more than one occasion, usually involving a steel of unknown origin that has work hardened to the point that HSS won't touch it. I can sharpen drills by hand ( after a fashion ) and the technique I use for sharpening is to present the masonry drill in exactly the same way I would with an ordinary drill. I should point out that I have only used these drills for opening out holes already drilled. Also the carbide tips are very small and prone to breaking. I only really use this as a last resort.
|Capstan Speaking||02/06/2015 22:07:49|
177 forum posts
Definitely do-able if you can't buy a proper t.c. drill.
Grind the negative rake off the end. Even then the "top rake" is an unhelpful 90 degrees.
The tip is soft-soldered in so the slightest heat and it's gone.
|Bob Brown 1||02/06/2015 22:27:42|
1016 forum posts
You can buy masonry bit that have a ground edge to drill a variety of materials including steel see **LINK**
To quote "High performance bits with multiple diamond-ground carbide tips.
I've used them to drill though aluminium then into brick also wood into brick/concrete block.
Edited By Bob Brown 1 on 02/06/2015 22:29:37
|2645 forum posts|
If you need to open up a hole in tough material you can use a Glass drill as it is, the leaf shape works quite well.
19135 forum posts
Couple of pics of some commercial TCT twistdrills I have to give you an idea of how to grind, tips are brazed like most masonary drills so will stay put. Looks to hace a 4 facet type grind with a very shallow angle to the first edge .
Edited By JasonB on 03/06/2015 10:05:46
|Gordon W||03/06/2015 08:51:10|
|2011 forum posts|
Masonry drill quality is very variable, all the decent ones I have the tips are brazed on. Sharpening is quite easy, just a sort of 4 facet spade drill. Cheap diamond disc in angle grinder is the easiest and cheapest way, touch up on green grit wheel. I've done this mostly when drilling in multi-media jobs.
|Jon Gibbs||03/06/2015 09:05:39|
|739 forum posts|
I've had some success with spear point tile drills if this helps.
The other option is to try something like the Bosch Multi-construction drill bits but these aren't as sharp from my experience.
In both cases high drilling pressures are needed.
|Danny M2Z||03/06/2015 09:42:04|
892 forum posts
Nice photo's Jason, I had always wondered if it was worth attacking my brazed tip masonry drill bits with a suitable grinding wheel. Unlike another thread the grinding wheel striations are a part of being a practical bloke. I bet the hole won't mind
* Danny M *
|John Stevenson||03/06/2015 09:58:48|
5068 forum posts
Ground quite a few up to get John out of trouble.
Diamond wheel and grind 4 facet, they work fine but don't expect H7 tolerance.
Try to use a decent drill, anything that has a chrome shank is suspect.
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.