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projectnut
11-30-2012, 10:27 AM
How many of you have sets of metric drill bits, do you find you use them on a regular basis, and where did you get them? The reason I asked is that when I got a new DRO for the mill of course all the fasteners are metric. Being somewhat stuck in fractional measurements I don't have many metric drill bits. I have all the fractionals up to 1 1/2" and the letters and numbers, but never found much of a need for a metric set. Metric fasteners aren't new to me. In fact I have several sets of metric taps & dies. However even the metric taps I have call out fractional hole sizes.


I've looked at Enco,and all the the "discount" tool houses and none seem to have very much to offer. About the most complete sets I've seen are at MSC, and they seem a bit pricey. So the question remains is it worth it to buy a set of metric bits? For general purposes it seems there are fractional, letter and number drills within .0001 or so of the most popular metric sizes. Is it finally time to move into the 21st century?

firbikrhd1
11-30-2012, 10:47 AM
I've considered getting some in the past, mostly to fill in small incremental diameters between the drills in the sets of number, fractional and letter drills I already own. So far I haven't really had the need to get them though so I haven't done it. It's on my list I guess but when I buy drills I buy quality, not the cheapo Chicom stuff and the money spent on drills I may never need can be spent on things I'd use more often. I find that I use my fractional drills most, followed by number and then letter drills.

KiddZimaHater
11-30-2012, 11:01 AM
If you already have all of the fractional drills, plus number and letter drills, then you've got 95% of the field covered.
Most metric drills only differ by a few thousandths, so getting a complete set is kinda pointless.
You can always 'round up' to the nearest drill size for drilling thru-holes or tap holes.

sch
11-30-2012, 11:16 AM
Ditto with KZH, standard 115 drill set will pretty closely cover metric sizes in reasonable size holes above 2mm. Below that it is hard to be precise but the variations become 0.002 or less difference
one drill to the next. Enco took a flyer in 2009 with a 115 or so drill set in a nice box with 0.05mm delta 1.6mm to 2.4mm then 0.1mm delta size from 2.5 upto 13mm drill set for $122. Don't recall
source but not stamped chinese and the box is much better grade than the chinese boxes I have seen for the inch sets. Metallurgy seems ok for the ones I have used. However the offer was never
repeated and there has been nothing similar in the catalog since. This sort of set is readily available in Europe.

Juergenwt
11-30-2012, 02:18 PM
I don't know what kind of work you are doing, but if you are doing metric work and you don't mind having to constantly convert and than check three different drill sets for the best match -
than you have enough drills to do the job. Tip for your metric taps : To find the correct tap drill just subtract the pitch from the nominal size. M6, pitch 1mm, 6-1=5mm tap drill, M10, pitch 1.5mm, 10 - 1.5 = 8.5mm tap drill. So for a 5mm tap drill (5/25.4 = 0.197) a #8 drill would be your best choice. For a 8.5mm tap drill (8.5/25.4 = 0.335) a letter "R" would be OK.

oldtiffie
11-30-2012, 02:47 PM
Metric drill sets can be a problem as the usual range is in 0.5mm (~0.02") increments which are larger than the normal inch set increments (1/64" ~ 0.016"). I usually use my "inch" sets as it can matter for tapping drills for the smaller metric tapping jobs (say M4 and downwards).

Most tapping drill tables have alternative drill sizes as well.

JohnAlex141r
11-30-2012, 03:57 PM
I just get mine from "KBC". (KBC.com - although I use the canadian site)

With few exceptions, all of my fractional, number, letter drills have not seen the light of day in a decade or two.

So, metric drill sets can replace all of the above. I have sets 1mm - 5.9mm, by 0.1mm, and 1mm to 13mm by 0.5mm. (6.35mm = 1/4 inch, 12.7mm = 1/2 inch)


(I still have some long drills in fractions, and small number drills 61-80, but all of these I don't use more than once or twice in a year)

Another JohnS.

Jaakko Fagerlund
11-30-2012, 04:48 PM
Metric drill sets can be a problem as the usual range is in 0.5mm (~0.02") increments which are larger than the normal inch set increments (1/64" ~ 0.016"). I usually use my "inch" sets as it can matter for tapping drills for the smaller metric tapping jobs (say M4 and downwards).
Sorry, but metric drills are readily available in 0.1 mm or even in 0.05 mm increments. The usual "drill set" goes from 1 - 13 mm with 0.5 mm increments and the usual addons to that are the tapping sizes 2.5, 3.3, 4.2, 6.8, 8.5 and 10.2 (M3 - M12). And usually the 0.1 mm incremented sets come in 0-6 mm range and 6-10 mm range.

However, it is very rare that you would need anything but the 0.5 mm increments and tapping sizes.

TR
11-30-2012, 04:55 PM
Sorry, but metric drills are readily available in 0.1 mm or even in 0.05 mm increments. .

Not common in Australia.

Peter N
11-30-2012, 05:18 PM
Not common in Australia.

I know that people say NZ is like living 30 years behind the times, but I thought the Aussies might be a bit more with it :)
Been very common over here for as long as I remember.

Rich Carlstedt
11-30-2012, 05:19 PM
I have Fraction/number/Letter/and Metric, and use all.
I see no differences in threads. As comfortable with Metric as I am with USA, BA or non-standard pitches .
If you work with doing odd jobs, that is, repairing all manner of threads, then there are not enough drill sizes in the world.
Case in point, (didn't need a drill however) my friend brought me a 1800's antique to fix as it had a single 5/16-24 (.312)screw that was stripped, as was the hole.Putting a new 5/16 screw in was very marginal so I used a .324-32 tap I had and made a new screw for him.
If you work building new stuff, then having lots of drills is not needed IMHO.

Rich

oldtiffie
11-30-2012, 05:34 PM
Originally Posted by Jaakko Fagerlund

Sorry, but metric drills are readily available in 0.1 mm or even in 0.05 mm increments. .


Not common in Australia.

Yes they are - any amount of tool suppliers - one example:

http://www.machineryhouse.com.au/Drill-Jobber-Sets

mike4
11-30-2012, 06:22 PM
The availability only depends on where you look , I have managed to obtain two sets from engineering supply businesses off the shelf.
Local hardware are way over priced, like most things ,have a good look around the better suppliers.
Most professional workshop suppliers have had them on the shelf for years.
I dont buy in ones and twos , usually a packet of ten of the most commonly used sizes.
Michael

TR
11-30-2012, 06:41 PM
Thanks.

bob_s
11-30-2012, 07:50 PM
Metric drills yes; for everything metric - printers, cars, computers

Canadian tire used to sell Dormer/SKF

The Artful Bodger
11-30-2012, 07:59 PM
I know that people say NZ is like living 30 years behind the times.....

Thats just your nostalgia kicking in!:rolleyes:

randyjaco
11-30-2012, 08:02 PM
I bought a nice set of metric drill bits 2 years ago while I was in Germany. I have yet to use them 8^(
My fractional, letter and number bits have served all my needs.

Randy

oldtiffie
11-30-2012, 08:13 PM
The big advantage of a metric drill set that advances in 0.01mm steps/increments is that the step of 0.01mm is about 0.004" which should just about cover most likely requirements. The problem (and cost) of buying single drills may be availability when you need it.

marinusdees
11-30-2012, 09:28 PM
Years ago ENCO had a retail store in Seattle. I was there and some guy said to me,"Buy a set of metric twist drills. They are cheap and you will have every size you will ever need." I did and he was almost right. Close enough for guvmint work.

M Dees

Jaakko Fagerlund
12-01-2012, 10:56 AM
The big advantage of a metric drill set that advances in 0.01mm steps/increments is that the step of 0.01mm is about 0.004" which should just about cover most likely requirements. The problem (and cost) of buying single drills may be availability when you need it.
I think you meant in 0.1 mm increments. And yeah, they cover almost everything that you need, especially when tapping for the size of screws that you can see with bare eyes.

marinusdees
12-11-2012, 11:54 PM
I can't see much less than 25 mm with "bare eyes". Whose "bare eyes" are we talking about here???

Fasttrack
12-12-2012, 12:57 AM
I've got a metric set ... haven't used it more than once or twice. To be honest, I can't even remember it's size. It came in a case like a 115 piece set and I think it went to 12 or 13 mm. You can tell how often I open it up to look at it ;)

I get a lot of drawings for scientific apparatus that are all in the metric system so you'd think I'd use them more often, but seems like fasteners are normally imperial - 2-56, 4-40, etc. And even when I just need to poke a hole in something, I end up converting it to imperial and using a wire sized, letter or fractional bit as appropriate.

I like having my set just because I know I have it if I need it, but on my current budget, I'd not buy it again.

vpt
12-12-2012, 07:55 AM
I work with metric all the time and not a single metric drill bit around. I can't think of a reason to have metric drill bits. Some one fill me in? Any time I am trying to work within the .00* for holes I am using a reamer.

J Tiers
12-12-2012, 08:25 AM
As for "searching three sets of drills for the best size", that is just silly. There are tables of metric sizes with cross-reference to and from imperial and US sizes, so it is a matter of a moment to glance at the list and see what drill of whatever system is the best to use.

Want a US size and have metric drills? no problem. Want a metric size and have US drills? Also no problem.

They are just numbers.



The big advantage of a metric drill set that advances in 0.01mm steps/increments is that the step of 0.01mm is about 0.004" which should just about cover most likely requirements. The problem (and cost) of buying single drills may be availability when you need it.

The problem with 0.1mm increment metric drills is figuring out which one of the several possibly applicable ones is best. 0.1mm (0.004") is not a large change in drills, the smaller size may drill that much oversize anyhow. ;)

In general, EVERY drill set is metric, and EVERY one is "imperial"...... Same set both ways. They are all just numbers, and every imperial size has a size in mm, it just may not come out to a nominal even 0.1mm increment, although tolerances probably cover many of the variations between the sets.

So, buy metric drills if your sense of political correctness means that you just can't stand nominal sizes that are not "exact" 0.1mm increments. And don't measure the drills, you might find out that some of them are actually fractional sizes due to tolerances, and then you would have to "bin them" to maintain "purity".

If you don't care about political correctness, use the drill size that is best, no matter what the units it is measured in are.

I have metric drills, US drills, US taps and dies, German standard sized metric taps and dies, Japanese standard sized metric taps and dies, chinese standard sized metric taps and dies... (those are not the same), inch and mm calipers and mics, whatever.....

Jaakko Fagerlund
12-12-2012, 01:59 PM
I end up converting it to imperial and using a wire sized, letter or fractional bit as appropriate.

Good example for not using imperial system - you need a table of the drill sizes.

Versus metric, where you just look at your drill shank and read the number that means 'diameter' as opposed imperials '#XyZ12, which is around 0.2874455 inches'.

The Artful Bodger
12-12-2012, 02:29 PM
For my really big stuff I measure in furlongs but for the finer jobs I use a sexatrigesimal fraction of a cubit.

J Tiers
12-12-2012, 09:29 PM
Good example for not using imperial system - you need a table of the drill sizes.

Versus metric, where you just look at your drill shank and read the number that means 'diameter' as opposed imperials '#XyZ12, which is around 0.2874455 inches'.

Not really....... For instance, because most drilled holes are for fasteners....... you want a hole for a bolt. The bolt size is in the same type units as the drills, so you pick a drill size with an appropriate number of units over the bolt size for clearance, and it is done. No need to consult tables, or add dried bat's wing, etc.

That works just as well for imperial as for metric.

People who use metric have this odd idea that one must have books of tables and conversions in order to use non-metric units. It isn't so, fractional drills are sized in the same units as the things that fit in holes (bolts, pegs, shafts, dowel pins, etc). People are practical, and don't make extra trouble for themselves if they can avoid it.

Perhaps metric folks have forgotten their own history, or need to go to the local farmer's market, where they probably can buy things in the local traditional units of measure...... I know this happens in Germany, I have seen it. Perhaps Finland is different.... it must make one think differently when summer is a time of year measured in minutes ;)

The Artful Bodger
12-12-2012, 09:55 PM
The one set of imperial drills I have is marked in fractions of an inch which does indeed match the common sizes of imperial bolts, shafts, etc but if I want to turn something down to fit an imperial hole I do need to refer to a book of tables or at least sharpen a pencil. Perhaps it is different if you can remember how many 'thou' equals 27/64".

Which brings up another point, why would anyone who likes to work in thousandths of an inch be adverse to the metric system?

J Tiers
12-12-2012, 10:19 PM
Which brings up another point, why would anyone who likes to work in thousandths of an inch be adverse to the metric system?

Averse to? not so much..... For most measurements, mm are quite convenient for "desktop measurements". meters, perhaps less so, but OK so far as they go. As for others, km are OK, but it takes a lot of them..... the only measurement in SI that I really hate is "hectares"...... I have a problem with "hectares", just don't like them.

I wish our clients would use metric.... I tried to convert them by doing all the drawings in metric, but they mostly complained. So I had to go back. Easy in CAD drafting.

What are the problems between mm and thou?

metric is so COARSE....... mm are 40 times bigger than a thou, 0.1s of a mm are 4x bigger, and even 0.01s of a mm are 4 "tenths" in size, essentially half a thou.

The machines are set up with dials in thou, not mm. The choice is to spend thousands on new machines (no problem for "Tiffie", who would no doubt "bin" the old ones with no problem), spend fewer thousands on all new dials and lead screws, or live with the conversions. Living with it is a lot cheaper.

The Artful Bodger
12-12-2012, 10:48 PM
Hectares? There are 100 of them to a square kilometre, about 2 1/2** acres. A square mile, well thats 640 acres, so much more natural eh?

Fortunately my machines are graduated in mm.

**I popped that fraction in just for 'good measure'!

Jaakko Fagerlund
12-12-2012, 11:56 PM
metric is so COARSE....... mm are 40 times bigger than a thou, 0.1s of a mm are 4x bigger, and even 0.01s of a mm are 4 "tenths" in size, essentially half a thou.
Good one :D

Of course you are kidding, our 'thou' is 0.01 mm, and don't really measure/mark in 0.001 range unless grinding something very accurate or sizing a tolerance fit.

About the coarseness: Just check regular metric bolts against imperial ones, the imperials are way more coarse for some reason.

JohnAlex141r
12-13-2012, 12:00 AM
The machines are set up with dials in thou, not mm. The choice is to spend thousands on new machines (no problem for "Tiffie", who would no doubt "bin" the old ones with no problem), spend fewer thousands on all new dials and lead screws, or live with the conversions. Living with it is a lot cheaper.

Not disagreeing, but I went from inch to metric.

I picked up an Emco Compact-8 when living in Europe, and it had metric dials and feeds crews. Yes, it was an adjustment. A *big* adjustment. A waving-hands what the F* is this!! type of adjustment.

Fast forward a decade.

My two mills are either CNC, and the other has a Sony DRO, with the switch permanently in the metric setting.

My larger british lathe is equipped with metric dial indicators on most axes. I *honestly* do not know what the pitch of the inch feedscrews are - anything accurate the indicators are used.

I guess it is what one is used to. Living back in North America, I'm a bit of an eccentric doing everything in metric, I do not have any fractional, number, letter drills around, other than a 61-80 set, and some of those "aircraft" drills that are really long.

I totally understand my colleagues working things out in decimal inches or fractions, or whatever, but I'm happy doing the simpler (IMHO) metric way.

One is not right and the other wrong, it's just, for me, when I really got used to both systems, metric was the preference for me.

Another JohnS.

J Tiers
12-13-2012, 08:43 AM
Of "coarse"... the screws don't matter much for CNC.

But if you have dials and screws that match on a manual machine, as most here will have, it is not possible to change just one thing, like the dial*.... a different dial will have mm graduations on it, sure...... but after one single turn, you have a problem, because now there is some "left over"..... 2.54 mm per turn, so now every reading on the second turn must be adjusted by 0.54 mm..... or 0.04mm, whichever. Easy-peasy to keep track of all those adjustments for well-educated europeans, of course....... Americans are not so well-educated, as you know..... ;)

Buying a new machine with different (metric) screw? No problem.

Converting a machine from inch to metric? More problem, maybe BIG problem..... change screw, dial, and nut, for every axis, for every machine.

It could easily be cheaper to buy all new machines, at the prices charged. Check out the price of parts for Cincinnati lathes as an example...... IIRC there were $200 bolts, and a leadscrew (standard) cost $4000 or so for a machine that costs maybe $2000 to $5000 on the used market. No clue what a metric upgrade one would cost, but you also would need to spend more for the crossfeed and compound. You could go over $10,000 for the conversion at that rate.

If you made your own, much less of course, but then also much less accuracy, most likely. Ballscrew conversion might be possible for some axes, but might not fit everywhere, and is also not cheap at all.

* the chinese tried it, they called 1/8" (0.125") 4mm, and sold machines like that...... small problem there, I'd say.

Juergenwt
12-13-2012, 02:42 PM
J Tiers - If you are trying to push this into a metric vs imperial argument - you may succeed.
However - "WIN" you can not.
No matter how much you argue in favor of fractional, letter or number drills as well as imperial markings for lathes - it's like a chapter from Don Quixote.
Pick up a table for Decimal Equivalents and you find numbers in between fractions in between letters sometimes exactly the same size, sometimes 0.001 apart sometimes 0.008 apart and so on. It works - but not very good. That is not to say one should throw away the imperial drill set. I keep mine and use it - but I have to keep looking at my chart. A metric drill set would be much better. Smaller sizes by 0.1 and larger sizes by 0.5mm.

Toolguy
12-13-2012, 03:14 PM
I have a lot of inch and metric drills, taps, end mills, reamers, bolts, screws, sockets, wrenches, etc. Neither system is very hard to learn. I just use whatever fits the situation, no need to only do one or the other.

J Tiers
12-13-2012, 11:48 PM
J Tiers - If you are trying to push this into a metric vs imperial argument - you may succeed.
However - "WIN" you can not.
No matter how much you argue in favor of fractional, letter or number drills

I was not aware that I was arguing IN FAVOR of non-metric....... My point is that there are a lot of drill sizes, and drills are not known for drilling accurately to size.......

So if you have metric drills, probably you can get most of the letter, number, and fractional sizes, within the basic accuracy of drilled hole sizes. Then also, if you have only the letter, number, and fractional sizes, you can get most of the metric sizes also, again within the basic accuracy of drilled hole sizes.

Whether the drill is labeled metric, or labeled something else, it has a size in metric, or in thou, or fractions, etc. The size is physical, what you call it is just a number.

So if the drill is the right size, it doesn't matter whether it is labeled in mm or thou, or with a letter, or a fraction, at least not unless one is a person who cannot stand to see any fractional drill in the shop....

And, also, if you work with the old standard sizes of bolts, etc, fractional drills require no conversion, it is all easy.

Just like working with metric.... where if you have an M10 bolt, you know what size to drill.

It's all numbers.

As I said, I like metric..... I have measuring tools, dies, taps, whatever, in metric and in inch. But the machine lead screws are, and will stay, imperial (inch). Not worth the huge expense to change over.

Ian B
12-14-2012, 05:16 AM
JT,

It *is* possible to change just the dial on a lathe with an imperial feedscrew and get sensible metric graduations. Mine has it. The trick lies within the dial - the imperial dial is simply keyed to the feedscrew as normal. The metric dial is geared from the feedscrew, at a ratio of 125:127 (127 being the first multiple of 25.4 that gives a whole number). The result is that the metric dial turns very slightly faster than the imperial dial. As the user, you don't notice this, but it works perfectly!

Ian

willmac
12-14-2012, 05:56 AM
JT,
The metric dial is geared from the feedscrew, at a ratio of 125:127 (127 being the first multiple of 25.4 that gives a whole number).
Ian

Yes - this works very well, especially on a mill with a DRO. With that combination you can essentially forget about the pitch of the leadscrews and work as easily in metric or Imperial. My mill is set up like this (a German mill with Imperial leadscrews strangely enough).

EVguru
12-14-2012, 07:42 AM
It *is* possible to change just the dial on a lathe with an imperial feedscrew and get sensible metric graduations.

It's also possible to right royally screw it up!

My Harrison L5 was an imperial machine supplied to a school. When schools were required to introduce the Metric system the top slide received a new screw, nut and dial, but the cross slide uses a telescopic leadscrew that costs something like 750. The solution there was just to bung on a Metric dial. It cause me some wasted time and material when I aquired the machine as every 1.00mm cut I put on actually cut 1.27mm.

J Tiers
12-14-2012, 08:32 AM
JT,

It *is* possible to change just the dial on a lathe with an imperial feedscrew and get sensible metric graduations. Mine has it. The trick lies within the dial - the imperial dial is simply keyed to the feedscrew as normal. The metric dial is geared from the feedscrew, at a ratio of 125:127 (127 being the first multiple of 25.4 that gives a whole number). The result is that the metric dial turns very slightly faster than the imperial dial. As the user, you don't notice this, but it works perfectly!

Ian

Of course...... there was even an article in the Home Shop Machinist (or maybe MW??) about that. I am well aware of that. it works for crossfeeds, etc. Not so well for the leadscrew, as you still have to throw away the thread dial. Of course real metric thread dials are more trouble than they are maybe worth, in general (4 or 5 different gears? Ai weh ist mir).

Some lathes have been MADE with the feeds having conversion dials on them offering BOTH metric and inch.

But, there are no available "kits" for that purpose, and the gearing is rather intricate due to the size. Gear backlash is a consideration with that system, and needs to be eliminated..........otherwise the inch and metric would get out of synch for reversing , as for boring vs external turning (no problem if you just replace inch with metric). I strongly doubt that the average shop or HSM is going to want to do that as a "home brew", although I might if sufficiently motivated, and I had nothing else to do, which last is not likely.

I suspect that many years of looking up in tables or using a calculator would not add up to the time required to make the conversion dial. But it might be an interesting project.

Mcgyver
12-14-2012, 09:05 AM
I know that people say NZ is like living 30 years behind the times,

I have an uncle there who says 50......but a great number of us wish our country was like it was 30 years ago so hold on to what you've got! :)

ed_h
12-14-2012, 12:08 PM
I've struggled with organizing drill bits for a long time. My current approach is to not maintain separate sets, but merge them. I built four shallow trays that nest into two drawers of a tool box. There are I think around 180 compartments. The compartments are marked with the "nominal" size (fraction inch, letter, number, or metric size), and also the decimal inch size. They are in order of size, so all four systems are interleaved. Except for the largest sizes, each compartment can hold multiple drills.

I don't have, nor do I aspire to have every compartment filled, but if I have a bit, it has a compartment.

Much of the time, I select a bit by it's decimal inch size rather than its nominal size. The system also suggests alternative sizes if I don't have the size called for. Here's a pic:

http://bullfire.net/Misc/SDC11617a.JPG

This anal enough for you guys?

Peter N
12-14-2012, 12:26 PM
I have an uncle there who says 50......but a great number of us wish our country was like it was 30 years ago so hold on to what you've got! :)

It is a fantastic place I must admit. I got offered a job in NZ, and also offered the chance to try it out to see if I liked it, so I spent 3 months living & working out there in 2005.
Loved it, but just not *quite* enough to pack up the family and move around 13,000 miles away from home.
But to anyone who has ever been then my advice is GO there. Sell the car to fund the trip, you can buy another when you come back, mortgage the cat, take out a loan, get a salary advance but you must at least visit this place, so much amazing stuff - and people - going for it.

Bob Fisher
12-15-2012, 07:31 PM
McMaster Carr sells a metric drill/tap organizer for cheap. It has a spot for the tap, tap drill, and clearance drill.also has the same for the fine metric series. I also have an English version, they are the first place I go when I have to tap a hole. You never have to look at a chart or find the right drill. Bob.

JohnAlex141r
12-16-2012, 01:31 AM
Of course...... there was even an article in the Home Shop Machinist (or maybe MW??) about that. I am well aware of that. it works for crossfeeds, etc. Not so well for the leadscrew, as you still have to throw away the thread dial. Of course real metric thread dials are more trouble than they are maybe worth, in general (4 or 5 different gears? Ai weh ist mir).


Certainly. On my big lathe, old British Iron, I just use 0-25mm dial indicators, stuck on with magnets/aluminum brackets. I keep meaning to put a DRO on. One of these decades.

I can't honestly say what the feedscrew pitches are, nor how well the graduated collars are engraved - I *never* bother to look at them. The gearbox came with metric threading and feeds built in (says so on the plates!) , so no issue there, other than changing 2 gears as per instructions. Seems to work just fine.

My 2 8" lathes are metric.

Working 100% in metric is my choice, I just find it easier, but if one enjoys inches, so what?

Another JohnS.

marinusdees
01-13-2013, 06:58 PM
Even the ones I can't see with bare eyes which is many of them, unfortunately.

Georgineer
01-14-2013, 10:03 AM
It's also possible to right royally screw it up!

My Harrison L5 was an imperial machine supplied to a school. When schools were required to introduce the Metric system the top slide received a new screw, nut and dial, but the cross slide uses a telescopic leadscrew that costs something like 750. The solution there was just to bung on a Metric dial. It cause me some wasted time and material when I aquired the machine as every 1.00mm cut I put on actually cut 1.27mm.

I use a pre-war Myford ML4 and the dials are marked 0-80. It took me some time to realise that one turn of the dial actually feeds by 83.3 thou (12 tpi screw). However, it does mean that I'm nearly metric, because each turn of the screw feeds by 2.1 mm.

George

tylernt
01-14-2013, 10:56 AM
If you work with doing odd jobs, that is, repairing all manner of threads, then there are not enough drill sizes in the world.That's when you drill with an undersize bit, turn a piece of O-1 on the lathe to the desired diameter, harden it, and grind it into a D-bit reamer.