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Dormer drills A095

Discussion in 'Tools and Materials' started by DIYalot, 29 Jun 2021.

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  1. DIYalot

    DIYalot

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    Hi. In the late 60's and during the 70's as a kid I'd use my dad's Dormer drills. They were black. Good drills. About 10 years ago now I bought two metal boxes of Dormer drills, A095 N0.202 & A095 No. 18. Paid about £150 for both. from Greenwood Tools Ltd of Bromsgrove. The drills are tipped with a golden colour. But I'm not that impressed with them. They don't seems half as good as the Dormer drills I used as a kid. They seem to blunt quickly. And if the drill turns in the chuch, the chuck gouges out a bit of metal on the shank. I think I must have bought a cheaper set of Dormer drills, I mean inferior metal qualty as compared to my dad's old drills. Can you still get drills of the quality of the old Dormer drills? Like the ones bought say late 60's & 70's? Thanks. Rich
     
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  3. sxturbo

    sxturbo

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    There still very good but as is the way of the world, globalisation has kind of killed off the quality.

    Nowadays everything is made and designed to work for as short a time as possible. Whereas things used to be built to last (exception of cars)
     
  4. Swwils

    Swwils

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    Sounds like you are using TiN on aluminium.

    Not a great combo.
     
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  5. DIYalot

    DIYalot

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    Further: I just bought a Makita drill bit set (P-51873) "Titanium Coated" for £16 odd. Well I drilled about 6 holes through 3mm mild steel with the 6.5 mm drill bit. Now blunt and useless. I need drill bits that an industrial outfit would use. Drill bits that would bore through say 30 or 40 mild steel plates 3mm thick, before needing to be sharpened. Any suggestions? Thanks. Rich

    EDIT: Maybe I need to go to a website that caters for industrial, such as:
     
    Last edited: 12 Jul 2021
  6. sxturbo

    sxturbo

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    I've found the cobalt drill bits made by Heller pretty good
     
  7. DIYalot

    DIYalot

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    I was trying to do the math. If my Makita drill bit does 6 bores of 3mm mild steel before blunting, I'd have to buy 30 to get 180 bores. If each drill cost £1 (inc. postage) that would cost me £30 for 180 bores. If I bought an expensive 6.5 mm carbide bit for say ££30, then if I could bore 180 times with that drill it would cost me the same £30 for 180 bores. If the carbide bit cost me £25, I'd be quids in. :). I've just asked a supplier of carbide bits how many bores their 6.5 mm drill bit could do going throgh 3 mm thick mild steel. I am looking for a figure in the 180 range. :)
     
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  9. DIYalot

    DIYalot

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    I ordered a Heller set of drill bits (Heller Tools 990 HSS-Co Cobalt Stainless Steel Drill Bits). See what gives with these.
     
  10. JobAndKnock

    JobAndKnock

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    I've drilled my fair share of rolled steel joists and beams, often to attach timber bearers and the like. These are frequently made from electro arc furnace steel where all kinds of scrap can end up in the melt, which just shouldn't be there. That can include pieces of alloyed steels (such as the gears and half shafts from vehicle rear axles) as well as hardening/alloying minerals (e.g molybdenum as used in engine oil additives), so you are never sure what you are drilling into or how hard it will be.

    Whilst I've found Heller cobalt HSS (M42) twist drills to be good, I've also found that Milwaukee Shockwave HSS (M42) twist drills have an edge, being less likely to snap in use but also stayingvm sharp longer (e.g. between 8 and 12 x 5.0mm diameter holes in 6 to 10mm wall tube sections I did earlier this year on a multiple balcony job). 5.0mm is about the largest diameter I drill without first pilot drilling in a smaller diameter such as 3.0mm. I find this helps prolong the life of the drill bits, as does marking the drilling point with a centre punch and hammer and using a bit of oil or Trendilube as a lubricant/coolant (even 3 in 1 or WD40 help). Choosing the correct speed, often the lowest speed on a cordless drill is also essential to prevent tip burning as is constant pressure. Ideallybyou should be producing a long spiral swarf if feed, speed and pressure are right
     
    Last edited: 14 Jul 2021
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  11. DIYalot

    DIYalot

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    Okay, so I bought a set of Heller drill bits (HSS-CO DIN338 RN). I got them today and I opened up 3 already existing holes with the 6.5mm drill. So, the drill has managed to make 3 holes. I then drilled with a pilot drill a new hole, then tried to drill through with the 6.5 mm drill bit. Guess what - I cannot bore through. I'm completely flummoxed by my experience. There has got to be an answer for this poor performance. I did not subject the drill to a high speed and I have not pushed hard. But I did not use a lubricant. I'm drilling through 25mm square angle iron. I am assuming it's made of mild steel. I expected the Heller drill bits to bore through my 3mm thick angle iron perhaps dozens of times. I think I may need to contact the manufacturer and ask questions. I truly am confused by what I'm experiencing.

    EDIT: Logically, what's causing poor performance would be that the angle iron is made of a pretty hard metal.
     
    Last edited: 14 Jul 2021
  12. JobAndKnock

    JobAndKnock

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    I"ll refer you back to what I said earlier about electro arc furnaces which are used to convert scrap into steel. The steel from this type of furnace mainly goes to making rolled steel profiles in the UK, as used in the construction industry. Try a Milwaukee Shockwave twist drill before giving up

    Afterthought: An existing hole not being drillable may indicate that the steel may be work hardening (due to heat from the pilot drilling operation). This could indicate the presence of an alloying element such as manganese in the steel which is known to accelerate work hardening. You really do need to use a lubricant/coolant
     
    Last edited: 14 Jul 2021
  13. DIYalot

    DIYalot

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    When I reflect back, at one time saw a spark when drilling. Might have come from the metal I'm cutting rather than the wood behind it (drill I think was a bit hot). That might be a clue. Instead of buying another drill bit set, or replacing the 6.5 mm drill with an exact replacement, I probably should just buy a very high quality 6.5 mm drill. Which I beliieve is what is being suggested. Which in fact I was on course doing when I approached a firm selling drills for industrial use. The reply of which was: " I wouldn’t recommend using carbide drill bits if you are using a pistol drill as they are very brittle and need to be run at fast speed’s to get maximum performance out of them. I would probably recommend trying a cobalt drill they are tougher than the hss you are currently using."

    I bought Cobalt drills (Heller) and still no joy. Might buy a Milwaukee "Shockwave" drill bit as suggested. And use lubricant. Such as:
    https://www.ebay.co.uk/itm/353529634245
     
    Last edited: 14 Jul 2021
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