Questions about reamers

[Dave Jones 1Participant @davejones1]

Morning all,

Just out of interest I am in the process of buying a few different reamers and I was wondering why the majority of machine reamers all seem to be 1MT. I can obviously use a 2MT adapter to fit into my lathe tailstock, but why are they made 1MT when the vast majority of headstocks/tailstocks/milling machine are 2MT or bigger.

On a similar note, do people still use reamers for non critical applications. Going through old ME magazines from the 1950's and earlier they advise to use a reamer for almost every hole that is drilled. I understand the need for using reamers in critical locations (loco axle boxes for example) but have advances in drill bits removed the need for using a reamer in other applications (say steam fittings for example).

[Dave Jones 1Participant @davejones1]

[Paul LousickParticipant @paullousick59116]

The MT size probably depends on the diameter of the reamer. I only use smaller ones, up to 12mm diameter and use those with a parallel shank to hold in a chuck in the tailstock. Some of my larger ones have MT shanks.

I only use reamers for accurate holes and just drill for those without a tolerance. Just use a drill for holes prior to thread tapping.

Paul.

[Chris Evans 6Participant @chrisevans6]

I very rarely buy morse taper machine reamers and tend to buy "Chucking Reamers". Usually from MSC when they are on the offer sheet, they are an American owned company so a lot of metric and imperial sizes available. Depending on the intended use the chucking reamer can be a bit long on overall length, easy to shorten and an advantage when length required. A lot of time though I tend to "Double Drill" and produce a size hole without reaming, after 50 years of toolmaking I can still grind a drill ! Edit of post. The chucking reamers tend to be cheaper to buy.

Edited By Chris Evans 6 on 17/06/2017 09:09:44

[mechman48Participant @mechman48]

I just use chucking reamers for any reaming I need, I do have a couple of MT1 reamers but rarely used, I also have a set of adjustable reamers – 1/4" – 3/8" should I need to 'tweak' that minute extra .001", in essence well covered for what I do. For non critical applications I just use standard drills.

George.

[Dave Jones 1Participant @davejones1]

I have seen the adjustable ones before, but never got my hands on one. I can see how they are adjusted, however how do you ensure that they are set to an accurate diameter. Are the threaded sections marked or are they set with a micrometer?

[Clive HartlandParticipant @clivehartland94829]

I have never seen an adjustable reamer with a scale ? Maybe someone else has. Basically an adjustable reamer is used on a ream and trial fit, for instance king pin bearings. Ream and adjust the reamer until you get the fit you want. Smaller adjustable reamers maybe 8 mm downwards are used for giving clearance fits for pins on a jig assembly. Pins press fit in one piece and then the hole cleaned until it fits the pin and gives a push fit for assembly. I have a set that only moves the blades a few thou. and is quite enough to give clearance.

Clive

[not done it yetParticipant @notdoneityet]

I think you approach the target size by small increments, otherwise they become unmanageable and one risks breakages or gouges in the holes.

[egaParticipant @ega]

A good friend hit upon the idea of using an adjustable reamer as an expanding mandrel.

[Mike PooleParticipant @mikepoole82104]

I think it is just standard to put everything (drills or reamers) up to 9/16 or 14 mm on a MT1 shank. These days it does seem most lathes have a MT2 socket but MT1 was more common on small machines in times gone by. It is more satisfactory to sleeve down to MT1 than use a jump up adaptor which uses up bed length on a small machine and gives huge overhang. Sleeves are quite cheap and I just leave them on the drill or reamer if I have to keep swapping during a repetition run.

Mike

[Dinosaur EngineerParticipant @dinosaurengineer]

Reamers (& drills) were commonly supplied with M.T. shanks as the early drill chucks were not that accurate. However as drill chuck accuracy improved ( e.g. Albrecht ) , then it has become quite common to use chucking reamers.. In the 50s & 60s most engineering use reamers and drills were supplied with M.T. shanks to guarantee accuracy . Straight shank drills at that time were primary used for hand drills and drill presses were accuracy was not that important.

Edited By Dinosaur Engineer on 17/06/2017 20:39:57

[roy entwistleParticipant @royentwistle24699]

I have two adjustable reamers @1/4inch and @3/4 inch, both have an odd number of blades, so the use of a mike would be difficult

Roy

Edited By roy entwistle on 17/06/2017 20:58:25

[Mick HenshallParticipant @mickhenshall99321]

Is the only difference beteen machine reamers and hand reamers because a machine reamer doesn't have a square on shank so isn't a hand reamer, all my reamers have the square but I use them in my lathe mounted in a chuck with no problem, probably a daft question

Mick

[Neil WyattModerator @neilwyatt]

I use my hand reamers ina tailstock chuck, or even in a drill press, but I find that machine reamers I have are nicer to use.

I don't think it would be impossible to chop the tapered end off a blunt/damaged hand reamer and resharpen it as a machine reamer.

Neil

[ChrisBParticipant @chrisb35596]

Posted by Clive Hartland on 17/06/2017 18:22:12:

I have never seen an adjustable reamer with a scale ? Maybe someone else has. Basically an adjustable reamer is used on a ream and trial fit, for instance king pin bearings. Ream and adjust the reamer until you get the fit you want. Smaller adjustable reamers maybe 8 mm downwards are used for giving clearance fits for pins on a jig assembly. Pins press fit in one piece and then the hole cleaned until it fits the pin and gives a push fit for assembly. I have a set that only moves the blades a few thou. and is quite enough to give clearance.

Clive

There are ones with micrometer scales called floating reamers or David Brown reamers. The reamer has two cutting blades floating on the body which can be adjusted over a range of dimensions. Have one somewhere which I used at work for reaming thin walled precision bushes….very expensive stuff

**LINK**

[Clive HartlandParticipant @clivehartland94829]

Hi Chris, only £282.00 not bad if needed for a long contiuos job.

Clivve

[Chris GunnParticipant @chrisgunn36534]

Back when I was making EN24 gear blanks at Timsons 50+ years ago, twin bladed David Brown reamers were the norm, and do have a scale, but the scale is only used to apply an adjustment, rather than indicate the size. The EN24 was hard on reamers, but these were sharpened as a matter of course. I still have a few, and they occasionally turn up on secondhand tool stalls, at next to nothing and worth acquiring if they are David Brown.

Chris Gunn

[Howard LewisParticipant @howardlewis46836]

If it needs to be said, ensure that the tailstock is on the centreline of the mandrel and work, in both planes.

If not, the reamer is likely to cut more heavily, like a boring tool, and produce an oversize hole.

DON'T ask how I know! But I did make floating holders for hand and MT reamers, using ER 25 collets.

They don't make ER 32 collets with MT bores, so I made my own, MT1, 2 and 3.

Needless to say, since then have had little need of them. But they'll come in handy one day!

Howard

[Martin KyteParticipant @martinkyte99762]

Posted by Mick Henshall on 17/06/2017 20:58:05:

Is the only difference beteen machine reamers and hand reamers because a machine reamer doesn't have a square on shank so isn't a hand reamer, all my reamers have the square but I use them in my lathe mounted in a chuck with no problem, probably a daft question

Mick

Machine reamers have a much shorter lead than hand reamers. Which I would say is the main difference.

regards Martin

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