Hello,
The chassis for my next project has been galvanised. I need to remove the coating from areas where some of the bushes and foot pedal bar etc. attach
to it. Is there a difference between drilling these bores out or reaming them out? The pedal bar bore needs to be accurate to avoid play. I have a
feeling that this question will expose a high degree of ignorance on my part so go easy on me please.
Steve
Try drilling a hole in a piece of metal similar to what you will be using and check the shape of the hole , it will be trapezodial (not sure of spelling) in other words a rounded triangle. Reaming should make the hole circular. HTH, Mel
Drilling is far less accurate and especially on larger holes can produce non round holes.
But as you are only removing soft zinc over a pre- formed hole a drill should be fine if you use the same size drill as hole.
Rusty is right.
Always use a reamer where accuracy is required.
Thanks,
Can I use a reamer in a drill or hand tool?
Any idea of good places to buy them?
Steve
If you are simply drilling out pre drilled holes, just run a drill down them.
Reamers are precision ground and are expensive, and used to finish a pre bored hole to an exact size, usually for bores in bushes.
Drill a 1/2 inch hole in a piece of tin and just before the drill goes all the way through look at the hole shape. ( like rusty says).
A reamer has many lands ( edges) and as such keeps itself centred to the hole. Also it only cuts off a small amount of material and as such it is only
used to finish off a hole size. It is very accurate.
[Edited on 22/8/10 by omega 24 v6]
Just a note do not turn a reamer backwards or try to take to much of as it will jam up, i would not use in a drill if it jams it will snap.
And use cutting oil
If you're just clearing a hole so that you can put a bolt through, use a drill bit. Don't use a reamer as they are quite expensive, easily
spoiled and don't cut much material.
As said above - the reamer is used to finish off a drilled hole, to make it perfectly round (e.g. to take a shaft). If you have lots of
different-sized holes to deal with, then drill bits will be much cheaper than a range of reamers!
What may not be clear is that you can't use JUST a reamer...I know everyone says they are for enlarging an existing hole, but that is ALL they do...they have no ability to start a hole.
If your drill bits produce trapezoidal holes, try sharpening them properly.
quote:
If your drill bits produce trapezoidal holes, try sharpening them properly.
quote:
If your drill bits produce trapezoidal holes, try sharpening them properly.