What Drill Size For A .374" Reamer?

[sanddan]

I haven't used a reamer yet and want to have a light press fit between a piece of 3/8" cold rolled I am using for a tee handle on a chuck wrench I am making. Looking at Enco, they have a .374" reamer that would give me the press I want but what size drill do you use for that reamer? This is for a 6" chuck that mounts on my rotary table. The wrench that came with the chuck is a bit too short for my liking so I'm making my own.

 

[mikey]

Do you have a knurler? If so, that might be a better approach. You might also get by with just drilling 9.5mm hole. If you think a reamer is the way to go, take a look at this: http://yankeereamers.com/tech-info/

 

[chips&more]

A 2% to 3% smaller hole is a general guide line for machine reamers.

 

[mike837go]

Just to throw some [stuff] in the game;

The chuck key for my new lathe had some raised 'teeth' the middle of the handle. (I have no idea of the proper term. Knurling is quite mild for what was done to the handle. Hash stippling with a sharp chisel?)

The handle slid easily to nearly centered in the key and then a few taps of a hammer to seat it permanently.

 

[RJSakowski]

Given that you are making a one-off handle Why not make your cross hole first and turn the O.D. of the handle for your desired fit. You are not making a precision piece that has to be accurately aligned so a reamed hole isn't necessary. If you turn down the ends of the handle slightly and leave the center section of the handle a larger diameter, you won't have to press half the length of the handle.

Bob

 

[rick9345]

weld, or set screw from the end, save on price of reamer. knurling in center, many solutions, imagination and tools available
Have fun,its a hobby

 

[Bill Gruby]

Letter Drill "U" .3680.

"Billy G"

 

[Wreck™Wreck]

Just to throw some [stuff] in the game;

The chuck key for my new lathe had some raised 'teeth' the middle of the handle. (I have no idea of the proper term. Knurling is quite mild for what was done to the handle. Hash stippling with a sharp chisel?)

The handle slid easily to nearly centered in the key and then a few taps of a hammer to seat it permanently.

That is a knurl, knurling need not be done in a lathe which limits the amount of force which may be applied to the work, many production parts are made with flat die knurling on thread rolling machines, change the dies from threads to knurls and one may produce some deep formed features. Virtually every fastener that you are familiar with has rolled threads. Like so

 

[sanddan]

1. No knurler
2. I was trying to use standard 3/8" stock and still get a press fit.
3. I might just tig weld it. A really small fillet might look ok. I just thought a press fit might look "more professional" but it is a hobby I guess.
4. Thanks, a U size drill I have. Just wasn't sure if the reamer would start into that size drill hole.

I think the material I am using might be 4140. Act's like hard material compared to the CR I usually work with. On another job I tried to tap it and quit before completing the hole as I feared it was going to break the tap. Should work great for a chuck key.

 

[Wobbles]

Generally, you can drill as much as 1/64" under and still start a fixed reamer in the hole. Most hobbyist will have a fractional drill set in 1/64ths. Adjustable reamers may allow even more.