Reamers – hand vs MT

[WolfieParticipant @wolfie]

I have a couple of hand reamers, but when I visited a colleagues workshop I noticed all his were morse taper reamers to fit in his lathe.

 

I need to get a couple more and I’d like to stick to one type.

 

Any difference or is it a case of choice?

[WolfieParticipant @wolfie]

[Sub MandrelParticipant @submandrel]

Hand reamers have a taper over the first inch or so, while machine reamers are effectively parallel and cut on the end. Most of mine are hand reamers, I only have one machine reamer.

 

Neil

[Tony MartyrParticipant @tonymartyr14488]

I have just posted a photograph of using a machine reamer to finally align the 6 main bearings of a triple expansion engine. I find MT reamers both easier to use in the lathe of milling machine than hand reaming.

[David LittlewoodParticipant @davidlittlewood51847]

Machine reamers are the only ones which can ream a blind hole to size all the way down. Conversely, they cannot be used by hand as there is no lead; only hand reamers are suitable for this job.

 

David

[WolfieParticipant @wolfie]

Now I’m more confused, what are ‘machine’ and ‘chucking’ reamers??

[Brian Dickinson 2Participant @briandickinson2]

Have a look here
http://www.taylorandjones.co.uk/ this may clear things up for you.

 

Happy christmas

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Wolfie, Machine reamers have a Morse taper for fitting into you tail stock, and I think chucking reamers have a parallel shank without a square at the top, to fit into a collet chuck.

 

Regards Nick.

 

seasons greatings to all.

[David LittlewoodParticipant @davidlittlewood51847]

Sorry Wolfie, they are, AFAIK, different names for the same thing: a reamer with no gradual taper at the business end, instead they have a 45 degree bevel which does all the work, the rest of the flutes are all to nominal diameter (usually + a tenth or two). They also usually come either with a morse taper shank, or with a plain shank with no flats for a tapholder. Hand reamers have a very, very gradual taper of about 2 diameters length, and the diameter at the front end is a few thou less than nominal. You may have to observe the width of the lands to see the extent of the taper more clearly. The cutting action is spread over all of the taper, but its purpose is to allow you to get the reamer into a hole while holding it in a hand tapholder – for which purpose they normally have square flats at the end of the shank.

 

You can use hand reamers in a machine, but you can’t (sensibly) use a machine reamer by hand. OTOH, as I said above, a hand reamer cannot ream a blind hole to the bottom.

 

Crossed with the other two posts; I don’t believe there is a difference between “machine” and “chucking”, other than what various makers choose to call them.

 

David

Edited By David Littlewood on 24/12/2011 17:28:14

[Steve WithnellParticipant @stevewithnell34426]

Chucking – goes in the chuck, Machine – goes in the machine tailstock taper? But both are parallel reamers as per note above.

 

Steve

[TerrydParticipant @terryd72465]

Posted by Wolfie on 24/12/2011 13:36:38:

I have a couple of hand reamers, but when I visited a colleagues workshop I noticed all his were morse taper reamers to fit in his lathe.

 

I need to get a couple more and I’d like to stick to one type.

 

Any difference or is it a case of choice?

 

Hi Wolfie,

 

Forget reamers, make your own D bits (see GH Thomas’ books) . Every bit as good as reamers for most model engineers purposes.

 

Happy Yuletide,

 

Terry

[David LittlewoodParticipant @davidlittlewood51847]

“Chucking – goes in the chuck, Machine – goes in the machine tailstock taper? But both are parallel reamers as per note above.”

 

No; like I said, it’s entirely up to the manufacturer, for example this one.

 

David

[Sub MandrelParticipant @submandrel]

Terry’s right, d-bits do as good a job as a reamer if well made and sharp.

 

But they can need a little help to make sure they start accurately (e.g. drill a lead-in at full diameter) unlike a reamer.

 

You can vary the end of a d-but to create flat, tapered (either way) or round bottomed holes.

The d-bit acts as a single point cutter, and if held rigidly enough can even be used as an endmill or slot drill or a flycutter. This means it can, used carefully, be used to drill a hole without a pilot (although this does mean along cutting edge. the main limit is the risk of overheating a carbon steel d-bit and blunting it rapidly.

 

Its also possible to make them from HSS blanks or even to use a boring bit as a D-bit if it is the correct size.

 

As the shoppping channel might say “Is there anything D-Bit can’t do…?”

 

Neil

 

[Ian S CParticipant @iansc]

A similar tool to the D bit is the tool makers reamer. In stead of being made like the D bit, the front end is cut at an angle of about 20*, and if its for one or two holes in brass or aluminium hardening is not usually required. I use that system on my hot air engines, drill under size, then make up a reamer from the shaft that will eventually go in the hole. An ordenary fluted reamer can leave corrigations lengthwise up the bore, not usually a problem, a spiral reamer helps to eliminate the chattering. Ian S C

[Ian S CParticipant @iansc]

Click on photos for a rough sketch. Ian S C

[WolfieParticipant @wolfie]

Whats a D bit?

[colin hawesParticipant @colinhawes85982]

Reamers are intended to produce a very close tolerance hole and are most likely to do this if allowed to float a little, to follow the drilled hole, by holding them the minimal amount in the drill chuck.Reamers with a taper shank are more likely to have a tendency to bore the hole due to inaccuracy in a tailstock.

Colin

[Sub MandrelParticipant @submandrel]

A d-bit is typically made from silver steel. the basic form is ground or machined away to a half-circle or D-shape in cross section. As George Thomas makes very clear you should leave it slightly THICKER than half the diameter as this stops it cutting on the edges and you get a true- to-size hole.

 

The end needs to be relieved at about 7-10 degrees to create a cutting edge, and you should also grind awa the non-cutting half of the end at a similar angle for clearance. You’ll have to get a mental picture of the cutting action to make sure you grind away the correct side.

 

Some people angle right across, to create an angled point at the cutting corner, others make it straight across to get flat bottomed holes.

 

Neil

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