How to drill these holes??

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lazyLathe

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Okay i have a question! :)

I made the small assembly tonight, just the small recessed bit.
I learnt how to use my boring head, so that was good and the fit is pretty good too!!
And i also used a hand file to get the radius parts so that when they are placed on each other the edges line up.
I have not used a file in many years.....
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Polished it up starting with 600 WP and oil going through to 1000 WP and then 2000WP and finally onto the buffing station and some Acrylic polishing compound that
works a treat on metal! One of the advantages of being in the dental field!!!

The test tube slides inside the small mount and i need to drill 4 holes, one in each corner all the way through the larger base part.
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I have never tapped a blind hole and would rather not snap a tap and have to remake the base.
So i will go the easy route this time!

How would i go about drilling the holes so that everything lines up nicely??
I was thinking of using some double sided tape and mounting it in the mill and then drill the holes all together.
If i do them as two separate parts i am sure the holes will not line up!

Is there another better way of doing this???
Any help appreciated!!!

Andrew

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No reason not to put them in your vise and dial off the positions. Do it in two operations. Remember, this is machine work, and mating parts is all part of the precision you can get using machine tools. Use dial indicators if you don't have a DRO. Make the clearance holes 0.005-0.010 larger than the screws and you won't have any problems. If you must have a close alignment, dowels are the way to do anyway, but it doesn't seem you have that situation. Just be careful dialing off the numbers and use a spot/center drill for all holes.
 
If you are a little scared of breaking your tap while going down the hole, there is usually no harm done if you go one size up with your tapping drill, 1/64" for imperial, 0.1mm for metric. A good quality high pressure lube does work wonders, just one drop either on the end of the tap, or down the hole. I personally wouldn't use paraffin or WD40 as a lube, they can't really take the cutting pressure of tapping or threading, also, give the hole a small dose of countersinking BEFORE tapping, even if it is a larger drill you use, that will stop the tread throwing up a 'volcano' shape at the top.

I have attached a very good tapping chart that shows what grip you get with variations of tapping drill sizes. If you can understand it, it shows you could easily go a couple of sizes bigger if say your were trying to put a small thread in a hard material.

Hope this helps


John
 

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Thank you for all the replies!!

Bogs, thanks for the chart!
I think that i do understand it.
The larger the drill bit, up to a max for the specified tap will determine the strength of the threads holding that specific bolt in place. ie- the larger the hole the less depth the threads have resulting in a weaker holding force? I grasp the facts but my vocabulary in that area is lacking... :D
As i said ask me about teeth and i will tell you anything...!

I did forget to mention that both pieces are Aluminium...sorry.

I was also thinking of taking the easy route and just drilling all the way through and securing with a nut on the opposite end.
Looks like i will be trying the blind hole method instead.
It will look much better when completed! :)

What is it?
It is a Laminar Flow Stirling Engine!
I have some other bits already made and polished, will post some pics of them tonight.
I have a burner or order and it should arrive this week sometime along with a few bottles of DNA (denatured alcohol)
as the fuel source.
I need to burner in order to figure out how high the stand needs to be.
I did cheat a bit by using an airpot for the power piston.... @#@#@#

As i mentioned earlier this is my first scratch build and it appears that i chose quite the project!
Not too sure if it will run...
But if i make it shiny enough it will look good on the bookshelf!!! @#@#@#@

Andrew
 
Very interesting. Which L/F Stirling are you building?

Randy
 
I just lost a whole post... must have hit the wrong button...... :crying:

The type of L/f Stirling is one out of my head.
I watched a few youtube vids and threw something together.

Here is what i mis-posted before...

That was enough for one night as that simple part took me close on 3 hours to make!

The next task was how to attach it all together.
I have tapped a few holes but they were mostly in wood so i was quite nervous about this part.
I really did not want to mess it up and have to remake anything.

Set it all up in the mill again to drill the holes.
This time i used my highly skilled method of locating the holes more commonly known as eyeballing it!

The holes came out nicely and everything lined up!
I was quite impressed!
Then it was time to tap the holes in the main base...

The bolts i used were 2-56 size and to me they are extremely small!!
I used a lot of Tap Magic when cutting the threads and it worked out perfectly!!

This is all the bits.
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And then assembled.
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I need to find a suitable o-ring to use as a seal so that it is nice and airtight.

Waiting on a nice burner to arrive and then i can figure out how high to make the stand.
Then i need to figure out how to attach the stand to the main base...

So far i am enjoying this build!

Andrew

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Thanks Turbo!!!!

Good news everyone!!!

It is alive!!!! <<<
I decided to put it together and see if i had made a lemon or if it would actually run.

I decided against using o-rings to seal the test tube and instead used High Temp Gasket Sealer.
So the test tube is sealed into the screwed on plate and i also added a gasket between the plate and the main base.
It is super airtight!

Holding it in my hand over a small flame for 10 seconds and the flywheel starts to oscillate and then off it goes!
Nice and slow due to the heavy brass flywheel.
I actually prefer the slower motion because it gives you a chance to see what is going on.

I will post a short build log and a video of it running when i am done the base.

For now i just uploaded a short clip to youtube to show everyone it actually works!
Absolutely no measurements or dimensions were worked too!
Beginners luck??

Will post a link to the video shortly!

Thanks for all your help and encouragement!!!

I am a happy camper!!!!!! clap1#$#$

Andrew
 
Great runner Andrew.

I am a bit of a fan of these types of engines, and over the years, I have watched how the lamina flow types have been progressing, Some got super technical with what you stuff into the tube and what position to have the flame, down to moveable inserts to get the things to work. Eventually they will become less complicated and get to a stage where I will give it a go.

Again, very nice and well done.

I bet you've got a grin on your face from ear to ear. Little engines get people that way when they get them to run.

John
 
Andrew

Way to go.

Cool Video. Once it starts running it just seems to want to keep on going.

I'm looking forward to the build log. The Sterling engine in all its variations has always fascinated me.

Tony
 
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