Parallel Reamers?

All my reamers seem to have a lead or taper to them on the end. This is of no consequence for most jobs but sometimes I need to ream a deep hole and the Parallel part of the bore isn’t long enough. Can you buy almost fully Parallel reamers for use as a second operation? Any links appreciated if you can TIA.

If you use a chucking reamer you should be ok as the only cut on the 45deg lead, I do have one or two old fashioned reamers that cut on the front as well like an end mill and have used these in the past to ream blind bores like you need on hand pumps.

As per Bernard's comments, but I'd also suggest that most conventional machine reamers should work too.

i.e. hand reamers, with a square drive on the end for a tap wrench, tend to have a tapered lead -in, whereas machine reamers with a Morse taper on the blunt end, cut on the leading edge.

Bill

I almost always use machine reamers these days with plain shanks they will ream to within about 1mm of the bottom of a blind hole

How about finishing the hole with a D-bit ?

Sounds good Jason, where did you get yours?

Edit: I’ve just bought a set online.  

Edited By Vic on 25/09/2023 22:20:28

In summary, MACHINE reamers cut a sized hole from the tip whereas HAND reamers cut a hole that is only to size about half way along the reamer onwards. You can't cut a blind hole to size with a hand reamer. ARC sell both.

Rod

Mine are mostly ARC with a couple of YG-1 for the smaler sizes ARC don't do.

If you reduce the chamfer at the front of the reamer, ie to get closer to the bottom of the blind hole, you will need to use a flat tool of some sort , and of course will need to reduce the amount left in the hole for the reamer. When I blind ream holes for pistons to use one circlip, I have made a pre reaming tool with a 0.1mm corner chamfer, essentially sharp, from centre cutting 3 flute or 4 flute endmills, ground about 0.1 to 0.15mm smaller than the final reamed hole.

As for the reamers, I buy the spiral flute ones with un even spaced fluting. These make very round holes right down to the bottom of the hole. I stop the reamer about 0.05mm from the bottom of the hole. A lot of places make un even spaced reamers these days