Ratcheting tap wrench or similar for 16mm reamer

[Alpha-Dave]

Hi all,

Now I’m drilling to 15mm and then reaming 16mm holes in 10mm mild steel, I’m finding that getting the reamer started straight is critical, but my current method of putting a point in the mag drill chuck, and then using a normal tap wrench is poor because the drill gets in the way of rotating the handles.

I can find ratcheting handles for small taps, but 16mm would be too big for the ones I can find. Am I missing a name for a tool or technique for this sort of problem?

My alternative is to put the reamer in the drill chuck and ream at 450-600 rpm. I’m sure a CNC milling machine would be fine with controllable speed, but that’s not an option for me.

What have I missed? All input appreciated, thank you!

 

[Rorschach]

You are reaming too much for a start. You want to drill to at least 15.5mm, even better if you can get to 15.8 or 15.9, reamers are only designed for a very small cut.

You can use the drill to do the reaming, turn the speed down as low as it will go and use plenty of lube.

 

[Alpha-Dave]

You are reaming too much for a start. You want to drill to at least 15.5mm, even better if you can get to 15.8 or 15.9, reamers are only designed for a very small cut.

You can use the drill to do the reaming, turn the speed down as low as it will go and use plenty of lube.

Thank you, 15.5 mm bit ordered from ebay, I will look for slightly larger too.

 

[Rorschach]

Oh and make sure you pilot drill as well, a 15.?mm drill will have a thick web and could wander and drill slightly oversize without a pilot hole of at least the web diameter.

If it were me I would be looking at something like: 6mm stubby (if possible) pilot, 15.8/9mm, ream. If it needed to really accurate I would use a spotting drill before the 6mm.

 

[Myfordman]

Go through your socket set and find a 12pt socket that sits nicely on the square shank of the reamer. Then look for a ratched combination spanner of the same size and use that to turn the reamer.

 

[Alpha-Dave]

Go through your socket set and find a 12pt socket that sits nicely on the square shank of the reamer. Then look for a ratched combination spanner of the same size and use that to turn the reamer.

9/16 or 14 mm it seems!

 

[Jelly]

You can use the drill to do the reaming, turn the speed down as low as it will go and use plenty of lube.

Doing this with a hand reamer works reasonably well as a one-off, but if doing a large number of holes I'd definitely stump up for a second hand (sharpened) spiral flute machine reamer to be able to do it at higher speeds, and less fear of reamer breakage.

I found the knack is in consistently applying enough force to ensure that the reamer cuts rather than rubs, but not so much that it becomes too heavily engaged; which is a feel thing unique to haptic feedback from the particular drill/mill you use.

 

[kenledger]

You dont say if your using a hand reamer or machine reamer. As Rorschach says you are taking out way to much, 1mm/40 thou is huge, it should be no more that 10 thou and that would be a hefty cut.
It should be a hand reamer as they are tapered where as a machine reamer is pretty much parallel.
One other thing, drill your first hole the use a very slightly bigger drill to het near your reaming hole. Reason is the first drill with cut over size slightly, the second drill will cut pretty much to size.
Sorry for the imperial sizes mention, that the way my brain was taught.

 

[Inspector]

Ken if the first bit drills oversize none of the subsequent operations will make the hole on size.
I think you had an Imperial/Metric moment and got your oversize and undersize mixed up.

Pete

 

[Alpha-Dave]

You dont say if your using a hand reamer or machine reamer. As Rorschach says you are taking out way to much, 1mm/40 thou is huge, it should be no more that 10 thou and that would be a hefty cut.
It should be a hand reamer as they are tapered where as a machine reamer is pretty much parallel.
One other thing, drill your first hole the use a very slightly bigger drill to het near your reaming hole. Reason is the first drill with cut over size slightly, the second drill will cut pretty much to size.
Sorry for the imperial sizes mention, that the way my brain was taught.

It’s difficult to find 15.8 or 15.9 mm bits that aren’t either really expensive or would take 3 weeks from China.

Interestingly the talk of Imerial and Metric got me wondering if I could get something closer; it seems that 5/8 is 15.875 mm, so that should be perfect, and readily available.

 

[TFrench]

I've got a massive amount of imperial Morse taper drills that came with the radial arm drill, almost none are metric! So frustrating when you're after a specific size.

 

[kenledger]

It’s difficult to find 15.8 or 15.9 mm bits that aren’t either really expensive or would take 3 weeks from China.

Interestingly the talk of Imerial and Metric got me wondering if I could get something closer; it seems that 5/8 is 15.875 mm, so that should be perfect, and readily available.

You can get a 5/8 drill from Chronos for £7.68. (Search Results | Chronos Engineering Tools)
If you drill is a morse taper type that would be even better

 

[Alpha-Dave]

You can get a 5/8 drill from Chronos for £7.68. (Search Results | Chronos Engineering Tools)
If you drill is a morse taper type that would be even better

Thank you. Fortunately I had a 5/8 on hand from doing some work on an old vice over summer. I have been buying from UK Drills on ebay, usually delivered in 2 days, which is plenty of time for my planning.

 

[Alpha-Dave]

Oh and make sure you pilot drill as well, a 15.?mm drill will have a thick web and could wander and drill slightly oversize without a pilot hole of at least the web diameter.

If it were me I would be looking at something like: 6mm stubby (if possible) pilot, 15.8/9mm, ream. If it needed to really accurate I would use a spotting drill before the 6mm.

The drill I have been using has 2 speeds, so I have been going 5.5 mm, 9mm, 12 mm at 1000 rpm, then 14, 15, 15.875 at 600 rpm, then ream at 600rpm. This has worked well.

In addition I used a centre point to locate on the punch marks I laid out. This added to a chamfering bit top and bottom adds up to 10 operations per hole!


The reamer worked well under power, you can see tiny shavings it was taking.


Thanks to all for the advice.

 

[Rorschach]

Great news, thanks for the update.