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Tool Chucking Reamers

Tool
Susquatch

Susquatch

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I don't have many reamers and what I have are individual chucking reamers purpose purchased for a given job.

It's always been my practice to either buy an undersize reamer to fit a standard size pin. For example, if the pin is 0.2500, and the reamer is 0.2485 for a press fit or 0.2515 for a slip fit.

I don't like to buy under or oversize pins to avoid leaving a problem for the next guy.

I'm not at all sure that this practice is correct. And it seems this information doesn't exist as standard practice anywhere that I could easily find.

Personal bitch - it seems that YouTube has done a hostile takeover of the interweb. I went looking for documents and only found YouTube videos. I don't want to watch a slough of videos to get this info. I did watch a few and they were useless. What ever happened to good old Google? It's become an ad riddled useless program forcing me to watch ad riddled useless videos.

I'm also contemplating buying some reamer sets instead of individual reamers. Some solid advice from real people would be much appreciated.
 
Well, having a quick look at McMaster-Carr, for 1/4"x1" alloy steel:
Std dowel: $8.57 per 25
Undersize: $6.35 each
Oversize: $23.62 per 25

So, I'll vote for buying std dimension pins if you were doing many applications of the one size. But if you're only doing a couple, then buying the over or under pins would be cheaper.
 
DavidR8 said:
Gets loads of results.
Click to expand...

That just hits a bunch of reamers for sale. I wanted technical info.

gerritv said:
What was your specific search text?
Click to expand...

I didnt want a bunch of reamers for sale so I searched on a dozen different things like:

- Choosing the right size chucking reamer

- All about reamers

- Selecting reamers, dowels and pins

- Reamers dowels and pins

- Chart of reamer pin dowel sizes

- Oversize undersize reamer pin dowel

I just want a good technical article preferably with some charts that provides good technical information on selecting reamers and pins for achieving slip fits, tight fits and press fits with chucking reamers and pins as well as the pros and cons of the different choices.

With that information in hand, I hope to be able to select a reasonably good set of reamers.

wmetfab said:
Perhaps think about purchasing a set of adjustable reamers. I had some and they were great. U used to have a set of Dormer but i foolishly sold my tooling cart when i had to downsize
Click to expand...

I thought about that too, but I figured an adjustable reamer would never be as good as a fixed size reamer. Maybe I should rethink that.

thestelster said:
I'll vote for buying std dimension pins if you were doing many applications of the one size. But if you're only doing a couple, then buying the over or under pins would be cheaper.
Click to expand...

Never even considered the cost. Thank you. I was looking at it from the standpoint of the end user ending up with something difficult to service. Non-standard pins would be a potential problem. But you are making that choice 10x easier!

What do you guys all do for pins dowels and reamers? Any good advice would be even better that a technical article.
 
Awhile ago there was a post about ‘tools you wish you had not purchased’ or something along those lines.

A month ago i bought a 17 to 19mm adjustable reamer. It worked great. Easy to adjust.
Wish i hadn’t bought it because for 3 times the price i could have bought a set of 6. Next time i need one I’ll get the set and end up with two that are 17 to19mm.
 
A good quality set of adjustable reamers will work very well - most, however, will be hand feed and have 3 to 4 cutters. They work well for very close fits where you just need a “hair” removed.

For chucking reamers you have ones for the drill chuck (obviously) and there are morse taper ones as well. The morse taper ones would be slightly better as they would centre in the spindle and not be susceptible to drill chuck run out.

So applications will vary- if you are pinning two things together you can drill your pilot through both pieces and use a tapered reamer and matching taper pin. If you are locating something onto another piece, your one pin should be fixed to the non-removable part (a slight press fit) and the removable part should have a hole the size (or just a hair larger) than the dowel pin you are using. This is where the adjustable reamers Can help (unless it is a blind hole).

The standard sizes of reamers should work for the best - mostly I have found that any press fits (bearings for example) require the exact diameter and the tolerances are designed into the bearing. I have quite a selection of reamers and for the most part, have not used the odd ball sizes that are larger or smaller than the standard.

I do have some adjustable chucking reamers that use a set screw to slightly enlarge or shrink the hole but I am typically trying for the precise size.

Not sure if any of that makes sense? If you are pressing a pin into a blind hole it is nice to have a threaded pin so you can slide hammer it out if need be.
 
IMG_1945.webp


@Susquatch check your machinist handbook for pinning information- might have what you need.
 
Susquatch said:
I just want a good technical article preferably with some charts that provides good technical information on selecting reamers and pins for achieving slip fits, tight fits and press fits with chucking reamers and pins as well as the pros and cons of the different choices.

With that information in hand, I hope to be able to select a reasonably good set of reamers.
Click to expand...

I think the short answer is that you pretty much will NEVER have the perfect reamer for a particular application!! Machinery's Handbook has a 60-page section devoted to the subject ("Fits") with lots of text and tables. Quinn's video (above) is a decent introduction to the topic.

OTOH, I lucked into a set of cheap Chinese over/under reamers (thanks @gerritv ) and I've accumulated on-size reamers up to 3/4". With those and choosing pins or shafts that are under/on/over size, I think I can get close enough for most purposes. And I've got a few adjustable reamers but I've never actually done anything with them.

Craig
 
trlvn said:
I think the short answer is that you pretty much will NEVER have the perfect reamer for a particular application!! Machinery's Handbook has a 60-page section devoted to the subject ("Fits") with lots of text and tables. Quinn's video (above) is a decent introduction to the topic.

OTOH, I lucked into a set of cheap Chinese over/under reamers (thanks @gerritv ) and I've accumulated on-size reamers up to 3/4". With those and choosing pins or shafts that are under/on/over size, I think I can get close enough for most purposes. And I've got a few adjustable reamers but I've never actually done anything with them.

Craig
Click to expand...

This is a GREAT answer Craig.

I skimmed through the section in Machinery's Handbook a while back and concluded it wasn't gunna help me unless I had a specific situation and specific goals.

I was looking for a more general guide that would hit say 90% of the situations a hobby machinist would encounter. More specifically, what kind of reamer set would satisfy that hobby need.

Your advice suggests I should just keep doing what I have been doing - buy my reamers pins and dowels as I need them for whatever application I need them for and forget the idea of buying my way to a 90% solution set.

One question. Why did you buy an over/under set instead of an over/nominal or under/nominal or over/under/nominal set? It just strikes me that any one of those will just end up spending a lot of money for something that will rarely get used. I know, buying individually will prolly be even more before the war is over, but at least I get exactly what I want that way..... On the other hand, I see you already had a nominal set. Is that why?
 
ChazzC said:
For reamers, try this:
https://yankeereamers.com/tech-info/

For fits:
https://www.engineersedge.com/tolerance_chart.htm

Quinn has a good video on the topic:
Click to expand...

The two links are similar to what is in machinery handbook. Specific answers to specific situations. That's what I have been doing.

I'm looking for a recommended set of reamers for hobbiest use so I don't have to keep buying individual reamers accompanied by the pros and cons of doing so.

I watched the Quinn video. Nothing in there I didn't know. That's basically what I have been doing.

It doesn't help me buy a reamer set that is a 90% solution for hobbiests.

I did like her hobbiest pro curves. Sort of intuitive if you ask me but it's nice to see it laid out like that.
 
Brent H said:
A good quality set of adjustable reamers will work very well - most, however, will be hand feed and have 3 to 4 cutters. They work well for very close fits where you just need a “hair” removed.

For chucking reamers you have ones for the drill chuck (obviously) and there are morse taper ones as well. The morse taper ones would be slightly better as they would centre in the spindle and not be susceptible to drill chuck run out.

So applications will vary- if you are pinning two things together you can drill your pilot through both pieces and use a tapered reamer and matching taper pin. If you are locating something onto another piece, your one pin should be fixed to the non-removable part (a slight press fit) and the removable part should have a hole the size (or just a hair larger) than the dowel pin you are using. This is where the adjustable reamers Can help (unless it is a blind hole).

The standard sizes of reamers should work for the best - mostly I have found that any press fits (bearings for example) require the exact diameter and the tolerances are designed into the bearing. I have quite a selection of reamers and for the most part, have not used the odd ball sizes that are larger or smaller than the standard.

I do have some adjustable chucking reamers that use a set screw to slightly enlarge or shrink the hole but I am typically trying for the precise size.

Not sure if any of that makes sense? If you are pressing a pin into a blind hole it is nice to have a threaded pin so you can slide hammer it out if need be.
Click to expand...

This is good info Brent. Sounds to me like a standard set and an adjustable set of reamers are in my future.

I confess I am surprised by how many of you guys like the adjustable ones. I would not have guesssed they would be worth the cost.

My mill is R8. So tapered arbour reamers are not ideal. I'd need to use adapters which stack up to undermine the advantage. I think I'm better off with straight shaft reamers in ER or R8 collets.
 
CWret said:
Awhile ago there was a post about ‘tools you wish you had not purchased’ or something along those lines.

A month ago i bought a 17 to 19mm adjustable reamer. It worked great. Easy to adjust.
Wish i hadn’t bought it because for 3 times the price i could have bought a set of 6. Next time i need one I’ll get the set and end up with two that are 17 to19mm.
Click to expand...

Link?
 
One comment. a 1.5 thou press is huge for a 0.250 pin. If you were to do that on a casting, it would likely break. A better fit would be a half though under reamer or less, or an on size reamer and retaining compound. Even 5/8 dowel pins are tight with a half thou press fit.
 
Darren said:
One comment. a 1.5 thou press is huge for a 0.250 pin. If you were to do that on a casting, it would likely break. A better fit would be a half though under reamer or less, or an on size reamer and retaining compound. Even 5/8 dowel pins are tight with a half thou press fit.
Click to expand...

Good point Darren. I don't pin cast iron. Never have, prolly never will. I usually use threaded joints. Maybe some day when I am older and wiser.

Wait - I am older! Not likely to get much wiser though. Mostly going backwards!

Come to think of it, I have used loose pins on cast parts - mostly just for alignment of covers, gaskets, and what not though. Never a press fit.
 
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