How useful are reamers?

Joined: July 12th, 2017, 12:19 am

July 2nd, 2018, 11:58 am #11

As Rkepler mentioned above, drill, bore, and ream are the way to get really good holes. Mostly you don't need this. We did once when we were making fixturing plates for the CNC machining centers in the shop where I worked. Had to have holes in the right places to properly locate fixtures on the plate (boring) and the right size to fit the hardened steel locating bushings (reaming).

I got to make a bunch of these, which was kind of cool, since it was steel and we mostly machined plastics in that shop.

Tim
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Joined: August 3rd, 2015, 8:49 am

July 2nd, 2018, 2:35 pm #12

Hmm, so if I wanted to re-bush my old VW carbs properly I should use a reamer, or send them off to somebody that does that service as a job. Good to know! Once I find the dang things again (and have pocket money so it isn't a pointless exercise)  I'll have to price out my options for comparison.
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Joined: January 11th, 2016, 8:57 pm

July 2nd, 2018, 9:49 pm #13

Be careful reaming bronze bushes - some of them are porous (sintered granules) and retain a fair amount of oil in the pores. Ream them and you close off lots of the pores and with no lubrication, the wear rate becomes impressive. May not be a major problem on butterfly bushes, but for a bush with some mechanical load or moderate shaft speed, it'll mean a short life for the bush.
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Joined: November 19th, 2014, 12:50 pm

July 3rd, 2018, 4:35 am #14

Beejay5169 wrote:use it slowly and take tiny cuts.
This is actually not correct. The general rule of thumb is 1/3 the speed and 3 times the feed. Almost everybody feeds drills far too slowly, and practically everybody feeds reams ridiculously too slowly.
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Joined: January 11th, 2016, 8:57 pm

July 3rd, 2018, 6:20 am #15

sniper1rfa wrote:
Beejay5169 wrote:use it slowly and take tiny cuts.
This is actually not correct. The general rule of thumb is 1/3 the speed and 3 times the feed. Almost everybody feeds drills far too slowly, and practically everybody feeds reams ridiculously too slowly.
I won't argue - as an electrician who occasionally has to shift half his workshop to get to his machine tools, all of my engineering reaming has been done with hand-powered, adjustable, parallel reamers, and the JapLish manual that came in the box said (translated) "Several small cuts will achieve a longer tool life and better material finish than one heavy cut. Clear frequently and use cutting oil, sparingly."

For power cutting / drilling speeds, I usually have to refer to The Workshop Bible.
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Joined: August 3rd, 2015, 8:49 am

July 3rd, 2018, 8:16 am #16

Beejay5169 wrote: Be careful reaming bronze bushes - some of them are porous (sintered granules) and retain a fair amount of oil in the pores. Ream them and you close off lots of the pores and with no lubrication, the wear rate becomes impressive. May not be a major problem on butterfly bushes, but for a bush with some mechanical load or moderate shaft speed, it'll mean a short life for the bush.
Thank you for the sensible advice! Though I'm hoping to not need to ream the ID of the bushings, just where they are fitted into the carb body (if I do end up doing it myself, that is).
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Joined: January 27th, 2016, 1:59 pm

July 3rd, 2018, 2:48 pm #17

And here, as I'm more found in the kitchen than the tool shed, I was like, "Well, you could just squeeze the citrus, but the reamer will be best for getting all the juice out. Just make sure you don't get into the pith."

:P
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Joined: September 16th, 2014, 7:01 am

July 3rd, 2018, 2:58 pm #18

When you start reaming organic materials you have to start worrying about materials incompatibilities - Citrus is acidic and aluminum has lots of ways to go rotten...  Stainless isn't immune. 
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Joined: October 8th, 2014, 2:05 pm

July 3rd, 2018, 3:49 pm #19

BruceBergman wrote: When you start reaming organic materials you have to start worrying about materials incompatibilities - Citrus is acidic and aluminum has lots of ways to go rotten...  Stainless isn't immune.
That's what glass and ceramics are for. If you're dealing with something mean enough to attack glass, you might want to reconsider your choice of feedstock.
If it ain't broke, I'll fix it!
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