Let's talk drilling...

[Mike Henry]

Thanks Rich - still learning something new every day. Looks like I'll be picking up some carbide spot drills in larger diameters.

 

[goldstar31]

Well, today I took delivery of:-


a set of round drill bits
a couple of boxes of metri drills to cover 1 to 10mm in 0.1 intervals( dear)
a set of stub drills- imperial
a scribing block for marking work

Then I have just had a phone call to either lend or sell me a Black and Decker 43000 profesional drill grinder to grind from 1/8th to 1/2" drills. The thing is 110V and I will need a transformer to drop my 240/250V to 110V AC

For a 90 odd YO. I'm going to be busy--- as I have large gardens as well.

Regards


Norman
NB

And on the 26th it is time for my next eye jab.

 

[jack620]

I also use a solid carbide spotting drill. They are excellent- very rigid and will cut just about anything.

 

[HennieL]

Thanks to everyone who contributed to this - most definitely an excellent "knowledge base". We need more of this type of discussion on other "common" workshop techniques... although we could probably skip the "how to hammer a nail into a piece of wood"
So, who's going to post the next topic?

 

[goldstar31]

So, who's going to post the next topic?

So moving a little, what about the other boring subject-- bore-ing?

 

[HennieL]

So moving a little, what about the other boring subject-- bore-ing?

I like it - especially boring very small diameter holes. My smallest boring cutter is 6mm, and I certainly don't feel comfortable using it... deflection, deflection, deflection... So, Goldstar, are you going to start a new thread, or should I?

 

[goldstar31]

I like it - especially boring very small diameter holes. My smallest boring cutter is 6mm, and I certainly don't feel comfortable using it... deflection, deflection, deflection... So, Goldstar, are you going to start a new thread, or should I?

So you are unable bore a hole smaller than 'under 3mm'? I lost my stuff in a wintr's storm that woukkd drill perhaps 1.5mm.
My problem is worsening macular degeneration- as mentioned earlier.
Currently, I'm trying again to read and then make 'small' tools from George Thomas's Model Engineer's Workshop Manual.
Really, the bits holders of 1/2" square and 1"x1/2" and a few little socket screws. Plus a pack of little bits of hss round.
There's a parting tool design for a 'bit' less than an eighth.
So this is obviously what can be put on a 7 x 19 lathe.
Best Wishes


Norman

 

[BaronJ]

Thanks to everyone who contributed to this - most definitely an excellent "knowledge base". We need more of this type of discussion on other "common" workshop techniques... although we could probably skip the "how to hammer a nail into a piece of wood"
So, who's going to post the next topic?

Hi Guys,
Just sticking with drilling for a moment, I can remember drilling 3/32" inch diameter holes through six inch lengths of 1/2" inch diameter Teflon rod on the lathe. The hole had to remain within a couple of thou of the center of the Teflon rod from one end to the other !

I made around 26 or 27 of these. Dormer in Sheffield, at the time made me a couple of long drills especially for this job. The way that I achieved doing this task was to place the Teflon rod into an aluminum block mounted on the lathe cross slide with a 1/2" inch hole bored through it, the Teflon rod was pressed into the block with the tailstock after heating it up. Teflon is very soft but happily withstands a high temperature, and drills easily.

There were some other constraints but the work was completed satisfactorily.

 

[goldstar31]

Well it has happened- or well? sort of
So I found that for only £15 that I could get THREE diffrent sizes of boring tools with a 90 degree and a 45 degree square tool bit holder at the ends. With a little bit of alteration each would fit my boring tool holder which fits the 4 way Myford tool turret. So it is a selection of boring tools which can slide and lock with the least overhang.

Cheap, cheep
So after all this discussion about drill grinding, I have a sort of pernent lend of a professional drill grinder which grinds drills from 1/8th to 1/2" diameters. 110 volt but a transformer came with it!
So I've always had a sort of abused 4 jaw independent chuck for my newer Myford. At a price way below the market price, I have one Virtually unused!
So to end a succesful afternoon, there was an offer to move the Sieg C4 from the study and have the Myford Super 7 with the power cross feed in and in a much warmer place to work.
We finished with a discussion on the fancy 6 staion Myford 5 station turret bit.

Apart from this- it rained.
More anon- including the rain

Norman

 

[SmithDoor]

My self in drilling on lathe is.
1) Center drill.
2) drill smaller hole in most cases.
3) larger drill still under size.
4) use a boring bar so hole turn true.
5) If have a Reamer then ream to size or bore to size.

Dave

What is your preferred method of drilling deep holes as accurately as possible using a lathe? I have been thinking about this for many years, trying to decide the "best" way to drill a reasonably large hole (say 16mm diameter...) for a depth of (say) 10 x diameter into steel. In your opinion (for hobbyists, and not using specialised through lubricated gun drills, etc.):

• would it be better to drill a small diameter pilot hole (say 4mm dia.) as deep as it can go, and then only drilling once using the final size drill, or
• would it be better to use a succession of increasing sized drills (say 4mm, then 8mm, then 10mm, 12mm, 14mm and finally 16mm

Using the second method one would make chip evacuation easier, and put less strain on the drill (both helping to increase the accuracy of the hole), but each successive drill bit would be "guided" only on the outer rim of it's cutting edges, which would make it easier to go off track. The first method would guide over the drill bit's full cutting edges, thus keeping the drill centered, but would create a much larger amount of chips to be evacuated, which would tend to push the drill off center, thus requiring more "peck drilling"...

I normally use the first method, but would appreciate your comments on this. Also, please feel free to comment on any other method you use, and also on drill bit types, twist rates, using a drill chuck vs using Morse tapered drills mounted directly in the tailstock, etc. etc.

Thanks for your comments
Hennie

 

[Bill Lawson]

SmithDoor is correct. My preference, after the spot or c’drill is to use a drill that is about the diameter of the web thickness of the larger drill 1/2” and larger, then bore to establish center line and ream to size.

 

[BaronJ]

SmithDoor is correct. My preference, after the spot or c’drill is to use a drill that is about the diameter of the web thickness of the larger drill 1/2” and larger, then bore to establish center line and ream to size.

Hi Guys,

I would suggest that its "Horses for Courses" ! You use whatever method that achieves the desired result !

 

[goldstar31]

My self in drilling on lathe is.
1) Center drill.
2) drill smaller hole in most cases.
3) larger drill still under size.
4) use a boring bar so hole turn true.
5) If have a Reamer then ream to size or bore to size.

Dave

I can assure you that the recommendation is excellent and I have used it many times - on garden gates.
Geo Thomas writing in his Model Engineers Worhshop Manual takes a mere 46 PAGES and if further reading was made I would gues that my figure in an underestimate. Our worthy BaronJ adds to both what Professor Dennis Chaddock and Thomas mention. Chaddock merely wrote a book on the to[pic after he had advised on the Manhattan Prpject as we all know went off in -- a couple of BIG bangs.BaonJ or my friend John wites on 4 facet drilling - it is good but not so Eath Shattering!.

More recently, NKirk Burwell and Heningewwaykits ugrades the Quorn to a Mark3 stus and simplifies* Ye Gods!) how to 'round off edges on drills and cutters and lathe tools. The kit is now VERY exp[ensive and should really come with a bottle of aspirin and a turban of damp hot towell.
And All this can be summarised in SIX short lines.

Now there is progress, folks-
or not