First time reaming question

[verbotenwhisky]

That's because nobody uses the metric system anymore.





The problem with using a reamer in the lathe is the tailstock can be off in any direction making the reamer ream a cone, the chuck only adds to this problem.

This is why there are boring bars.

Understood, however a standard Jacobs chuck generally comes equipped with .003 to .005 run out... I paid a great deal of money for my drill press (Porter Cable floor model) and the chuck was atrocious. I switched it to a ER32 collet chuck and it was dead on (expensive as well).

 

[SouthernChap]

That's because nobody uses the metric system anymore.

Thank you, that's very insightful.

 

[SouthernChap]

Over and undersized reamers are typically +0.001" and -0.001" around nominal size, or roughly +0.0254mm and -0.0254mm. Haven't seen any metric reamers offered at that spacing. Think I found some reamers at 0.05mm offset, but not less. Interesting that they are not common in metric. I've seen 0.0005" increments on imperial reamers.

Yep, it's odd, I just wondering if anybody knew the reason why.

Ah well, one of the mysteries of the world of machining.

I've been getting better at thinking in both systems recently because the shim stock I'm using is offered in increments of 0.001" (well mostly; I could have done with a 0.009" but there's 0.008 and 0.010 in my pack) which is handy on here where everyone talks in thou.

 

[RaisedByWolves]

Yep, it's odd, I just wondering if anybody knew the reason why.

Ah well, one of the mysteries of the world of machining.

I've been getting better at thinking in both systems recently because the shim stock I'm using is offered in increments of 0.001" (well mostly; I could have done with a 0.009" but there's 0.008 and 0.010 in my pack) which is handy on here where everyone talks in thou.

YES!

DO THIS!!!

We have been forced to implement the metric system into our work due to having dies build overseas and it has opened up new possibilities for us we never thought of.

Now that I own metric machines (Inch dials and screws, but you still need to make things for them at times.) this has helped me greatly. That and digital calipers, (Mit) those things are the easy button for lots of things.

 

[SouthernChap]

YES!

DO THIS!!!

We have been forced to implement the metric system into our work due to having dies build overseas and it has opened up new possibilities for us we never thought of.

Now that I own metric machines (Inch dials and screws, but you still need to make things for them at times.) this has helped me greatly. That and digital calipers, (Mit) those things are the easy button for lots of things.

My digital Mitutoyo 6"/150mm caliper arrived two days ago.

I'd been using a Mitutoyo dial caliper and a cheapy, battery devouring, crunchy travel no-name digital caliper up until now and boy is it nice to have the convenience of digital with the quality of Mitutoyo.

I bought it from a well established UK company that also sells Bowers stuff so I felt reassured they were unlikely to be selling the knock off mit stuff.

I rather fancy me a Mitutoyo mechanical 'counter' mic. I already have a plain 0-25mm mechanical Mitutoyo with the vernier scale for 0.001mm and a 'vintage' VIS tenths micrometer, I got for £30 or so from some vintage tools site or other but I do like the mechanical counter type.

 

[Parlo]

The chucking reamer that you posted does not have a taper of 0.0005" per inch. Machine reamers like this only cut on the 45 degree chamfer at the end. Running the reamer on the way out is preferred, they can sieze if they get too warm, keeping the reamer running will help prevent this.
Over & undersize reamers aren't really something to consider buying. In almost 50 years in toolrooms I have never needed one. Polish the shaft to the fit you want.
The standard increment for special metric reamers is 0.01mm ( 0.0004")

 

[RaisedByWolves]

The chucking reamer that you posted does not have a taper of 0.005" per inch. Machine reamers like this only cut on the 45 degree chamfer at the end. Running the reamer on the way out is preferred, they can sieze if they get too warm, keeping the reamer running will help prevent this.
Over & undersize reamers aren't really something to consider buying. In almost 50 years in toolrooms I have never needed one. Polish the shaft to the fit you want.
The standard increment for special metric reamers is 0.01mm ( 0.0004")

Funny, I read that the other day and thought BS, but apparently there is an extremely slight taper, more like one micron (.00004) per inch.

I had just looked this up.

We do use +/- reamers often in our shop quite often. If you're doing production Tool&Die work I can see how you may not use them, but we do mostly repair and need as many tricks as we can get. Our engineering department also comes up with off the wall requests, so there's that.

Heck, I can even shrink a buggered up dowel hole to better fit a dowel pin with an appropriate sized ball bearing, but this is edging toward Guerilla Tool&Die..

 

[WobblyHand]

Funny, I read that the other day and thought BS, but apparently there is an extremely slight taper, more like one micron (.00004) per inch.

I had just looked this up.

We do use +/- reamers often in our shop quite often. If you're doing production Tool&Die work I can see how you may not use them, but we do mostly repair and need as many tricks as we can get. Our engineering department also comes up with off the wall requests, so there's that.

Heck, I can even shrink a buggered up dowel hole to better fit a dowel pin with an appropriate sized ball bearing, but this is edging toward Guerilla Tool&Die..

They are great for "rescue" efforts, like when you find out your stock is 0.2505" diameter, to your surprise, and you already reamed the hole 0.2500". So grab the 0.2510" reamer, and life is good again . Ask me how I know...

 

[Parlo]

They are great for "rescue" efforts, like when you find out your stock is 0.2505" diameter, to your surprise, and you already reamed the hole 0.2500". So grab the 0.2510" reamer, and life is good again . Ask me how I know...

Or polish the shaft to the fit you require within a tenth.

 

[ddickey]

Reamers are twice the feed and half the speed of the same size drill bit.