Elmer's scotty steam passage drilling

[pmerritt]

Hi all,

I am taking a stab at building Elmer's Scotty engine and am at the point of drilling the 1/16" steam passage. I am worried about bit breakage as this hole is over 1.5" deep. I don't have any long 1/16" bits and the ones I've seen have the same flute length as the jobber drill. Any advice?

This is starting to be a trend - I reach a scary point in the build and move on to something else. Maybe some day I'll actually finish a project.

Thanks,

Peter

 

[Mosey]

maybe look for aircraft drills, as they are very long.
MSC has them 1/16" x 6" long for $4.34. you might want to get 2 of them just in case.

 

[bearcar1]

Peter, the major factor that contributes to drill bit breakage is advancing the quill too fast. What happens here is that the flutes of the bit get packed with metal bits and do not have time enough to be ejected clear the hole site and ultimately, as more and more cut metal packs into the already confined space it reaches a point of "no where else to go" and essentially binds the bit to the hole wall and *SNAP* scratch one drill bit. Not having the part being drilled securely held will couple with the bit flexing and will also lend itself to disaster. All of this may sound scary as the dickens but it does not have to be that way. #1, allow the drill bit to do the work, not the ham fisting that some operators employ. Be sure that the bit is sharp, if it is throwing a chip it is cutting, be gentle and apply only enough downforce to sustain the cutting action, no more, no less. #2, don't be in a huge rush to finish drilling the hole in one fell swoop, take your time and back the bit completely out of the hole to clear the chips out, both in the hole, as well as any that have built themselves up on the drill. Do it often and in shorter intervals as the hole depth increases. Use a lubricant (ooohhh ), this will help to wash chips away as well as reduce the heat buildup. #3, hold the part securely in a vice and provide some means of securing it down, remember, you're not boring holes in wood but are attempting a deep drilling operation in a piece of metal. Doing this will keep the piece from applying any side loads to the bit in use. If you follow these steps th_rulze your chances of success will increase ten thousand fold. Take your time, clear chip build-up, and keep the piece rigid at all times. You'll do just fine, good luck and let us know how you made out.
Regards
BC1
Jim

 

[Tin Falcon]

MSC sells tapper length parabolic bits this would be fantastic for the job. But MSC #: 01465046 a bit pricey @ $7.71 each
Tin

 

[pmerritt]

Thanks for the replies. You said what I know to do, it is just nice to have it confirmed before trying. I have already tapped the 4 2-56 holes so this drilling job should be a piece of cake!

Tin, I agree about the taper length drills. I saw them at enco for a little more that $1 each. However at that size you have to buy 12 at a time. It looks like MSC has a minimum of 10 - over $70 I'll give it a shot - very gingerly - with my jobber length drills.

Peter

 

[Tin Falcon]

the parabolic is nice for deep holes I use them when doing pen blanks
Tin