Boring and Reaming
Turbo Mini Forums

A couple of questions for you:

First of I want to bore two holes 9.0mm and 10.0mm now I know I need to drill the slightly under and then use a reamer to get them spot on but I can't find a good reference as to what size I should bore them to, anyone know the correct sizes? (I'm guessing 0.1mm or 0.2mm under)

Second I need to sleeve a 12mm hole, I'm guessing that if I try and force a 12mm rod in there it'll go hideous wrong and I need to enlarge the hole a bit for it to fit but can anyone advise by how much? I'm guessing there's a guide to clearance and interferance fit sizes out there but I can't find one.

Cheers

Being pedantic,Rob, but if you are boring a hole you can bore it to size. If, as I think you mean, you are drilling the hole then the allowance for reaming will depend at least partly on the material involved I,d say 0.1 mm is the most you would expect to ream out on most metals.

As to sleeving a 12mm hole, why do you want to force a rod in there ? why not put a sleeve in there and either bore or ream to finished size ?

As you have already noted, trying to put a rod (or sleeve)of the same nominal size as the hole will not work, there needs to be a small interference fit, again dependent on material.

Do you not have Zeus book or similar ?

Maybe contact a machine shop for their recommendations ?

like my zeus book, this also has most of the engineering answers on fits, drilling etc
http://www.cnctooling.co.uk/sutton-tools-e...black-book.html

With regards to reaming, it all depends on what you are reaming, what finish you need and what the fit needs to be? I would always choose to bore an accurate hole before reaming it.

With the sleeving, it depends on what materials you are using? using something like aluminium allows for more sqeeze than say mild steel, especially if you are going heat the part being sleeved? Is the sleeve the same material as the housing?

What length is the sleeved insert going to be?

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1/4mile in 13.2sec @ 111 terminal on 15psi

The good thing is your not talking about odd ball sizes. Best thing I can suggest is phone or go to your local Cromwell Tool store and ask them over the counter they will be able to sell you the correct drill and reamer combination you want, if your lucky they may have a drill reamer in the size you want or they can order it in and you will have it in a couple of days

Own the day

Exactly what are you trying to achieve anyway ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will