Hard spots in mild steel

[paul 1950Participant @paul1950]

drilling to fast may be the problem

[Alan RawlinsParticipant @alanrawlins60482]

Hi everyone, thank you for your replies. For a start, the steel is 12mm thick and black, not machined up.

My drill set up is a 750watt Makita fixed in a drill stand and has two speeds, High and Low, and I always use the low speed except for when drilling aluminium. I have never had any trouble with this set-up and the power of the drill is more than enough for drills up to 16mm as long as I have drilled a pilot hole first.

I came across the same problem in the same piece of steel, late yesterday using a drill of a similar size, and I then used another new Dormer drill, of the same diameter size, that I used earlier in the day. This time It drilled through the plate ok so my conclusions are that although they were all new drills, the very first one I used earlier in the day had not been sharpened properly.

Just to be clear about the drills, I have the box in front of me and the following information is on the box with the correct spelling.

DORMER

HSS TiN Coated Jobber Drill

Tin Tip

Din338

Brazil

As some one suggested that there are two drlils dormer and dorma, which is the more superior drill to buy?

[Neil WyattModerator @neilwyatt]

Dormer are generally considered to be world leaders in drill bit manufacture.

Dorma make windows and I think the ad Michael found had a typo in it.

Neil

Edited By Neil Wyatt on 16/08/2015 11:37:05

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Alan Rawlins on 16/08/2015 09:32:00:

Just to be clear about the drills, I have the box in front of me and the following information is on the box with the correct spelling.

DORMER

HSS TiN Coated Jobber Drill

Tin Tip

Din338

Brazil

As some one suggested that there are two drlils dormer and dorma, which is the more superior drill to buy?

.

Alan,

When Dormer drills were made in England, they were excellent quality.

I cannot comment on those made in Brazil, because I have never tried one.

As for Dorma … I have no idea whether it's a brand or a typo … but [as you may have seen on another thread], I don't trust manufacturers that use 'omage brand names !!

MichaelG.

[Neil WyattModerator @neilwyatt]

> I cannot comment on those made in Brazil, because I have never tried one.

I have several split point ones, they are excellent.

Neil

[Neil WyattModerator @neilwyatt]

I suspect a typo as this site lists lots of Dormer long series drills, a few 'Dorma' and all at eye-watering prices!

Neil

[KWILParticipant @kwil]

I only use Dormer drills A002, made in Brazil AND have never had a problem with the drill quality. Greenwood tools are my preferred supplier.

Inadequate level of applied and consistent pressure is often a cause of drilling problems, S/S is a good example of where this is all important.

Architectural feature, "Dormer" window, is spelt the same way and is not a "brand" rather a style.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by KWIL on 16/08/2015 15:04:14:

Architectural feature, "Dormer" window, is spelt the same way and is not a "brand" rather a style.

.

Useful to know that the Brazilian drills are O.K. … Thanks

It therefore seems reasonable to assume that Alan's steel is the source of his problem.

Sorry, I don't really understand why you mentioned the architectural Dormer … My objection was to "passing-off" [which generally presumes some similarity of product].

MichaelG.

[Neil WyattModerator @neilwyatt]

**LINK**

What's the opposite of passing off?

Neil

Edited By Neil Wyatt on 16/08/2015 15:43:07

[KWILParticipant @kwil]

What's the opposite of passing off?

Original and unique

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 16/08/2015 15:42:43:

What's the opposite of passing off?

.

Nodding off ?

**LINK**

MichaelG.

[MuzzerParticipant @muzzer]

Dorma is Latin for sleep.

[Neil WyattModerator @neilwyatt]

Nodding off ?

**LINK**

MichaelG.

Mornington Crescent

Neil

[Dave HalfordParticipant @davehalford22513]

I would blame recycled steel. I dont think they stir it much :O)

I've drilled a 1950's era 3" U section girder that had soft bits and hard bits with the same drill so it's not a modern problem

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