Open Column Launch Engine from Kit

[kvom]

Most metals will burr at the edges of exit holes. You need to get a carbide deburring "pen" that can be run around the edges of holes to remove the burr. The same applies to milled edges (those burrs can cut!). You can use a file or abrasive paper to remove those, but I also like the carbide deburring tool.

 

[zeeprogrammer]

You need to get a carbide deburring "pen" that can be run around the edges of holes to remove the burr.

Hi kvom.
One of these?

Any words of wisdom regarding use? I seem to do okay when I draw towards me...less effective when moving away. While it does a great job of deburring...it can (I can) dig in and not get a 'smooth' corner. Seems to start and stop. Is it just practice? Or some secret that newbies wouldn't know? How much pressure...that kind of thing.

Thanks.

 

[vlmarshall]

The right pressure, angle, and even deburring tip, will make a lot of difference. I usually hold them with my index finger curled around the back side of the tip itself, to help control the blade.

Try holding the handle at different anges to the work, leading the blade at a steeper, or shallower, angle, until you find what works for each particular blade style.

 

[zeeprogrammer]

When last we left our hero...he was crying uncontrollably. Let us give him another chance before we unceremoniously dump him for another hero.

As previously mentioned...I busted a drill bit in the piston. For those who have kept up with the serial matinee...(how many of you remember that?)...I had purchased additional material in anticipation of such a catastrophe. I've got 12" of 5/8" 1018 CRS ready to give up a piston.

Some of you may know this isn't the first time I have saved myself with additional material. That cylinder wasn't made with the material that came with the kit.

Unfortunately...I failed to provide for the possibility that I'd break a tool. i.e. the drill bit. (What...break a bit?...a tap? That only happens to other people. Not to newbies. Not to me.)

This weekend...we will have a piston. Come [EDIT: showed as 'trash'...I meant the double hockey sticks.] or high water. (Oops...the high water seems to be making progress. It just keeps raining and raining.)

 

[zeeprogrammer]

The right pressure, angle, and even deburring tip, will make a lot of difference. I usually hold them with my index finger curled around the back side of the tip itself, to help control the blade.

Try holding the handle at different anges to the work, leading the blade at a steeper, or shallower, angle, until you find what works for each particular blade style.

I had no idea there were different blade styles. I've only seen the one. Time to do some googling.

Thanks Vernon.

 

[zeeprogrammer]

So the busted drill bit...

A couple of members mentioned the possibility that the down force caused the piston to move down and that I might consider a V-block. One of the eagle-eyed members pointed out that I have one as he'd seen me use it. (A spy!)

I'm just trying to figure out how...

You'll note that the one end has a larger diameter. So even on the V block, the other end is hanging in the wind. Moving it to the left and cradling just the turned part would work for the wrist pin hole...but it doesn't look like the slitting saw can make it to depth. (Not shown are the 'pusher blocks' that Marv has discussed in order to hold the part with the vise.)

Seems no different than what I had where I used two parallels.

The instructions called for doing what I did...slit and then 'since we're there' drill the hole. I can see how it would help ensure the hole is 90 deg to the slit.

If I go with two separate operations...slit as I did it (forces are to the left...where I should have a vise stop) and then support the part from below and drill...how do I ensure the hole is perpendicular to the slit?

The instructions also called for parting off the excess after this. Why not do it before hand? That would make it sit nicely in the V block. Wouldn't have to part to size...just enough to knock off the bigger diameter?

Suggestions?

 

[zeeprogrammer]

Hey Vernon...seems we're playing badminton together but on different courts

What tells you to use one over another?...uh...the deburring pen blades?

 

[vlmarshall]

Hey Vernon...seems we're playing badminton together but on different courts
What tells you to use one over another?...uh...the deburring pen blades?

Sorry, good point; I'm dragging your thread off-topic with my posts! Briefly, some blades work better in holes than edges, some don't seem to work well anywhere, but I'm a packrat. The deburring tools I have at work have the hollow storage handles loaded with an even larger assortment. ;D

 

[vlmarshall]

If I were making that piston, (and didn't have a fourth-axis, "Speedy Spacer", or even collet blocks available ) I'd turn more of the stock down to the finish diameter, and clamp it with your V-block(s).

If you MUST do the part in two mill setups, find something (gauge blocks? Parallels? The slitting saw itself?) to fit in the slot and set on 123 blocks, or gauge blocks, something parallel... or just run an indicator across it, or even in the slot itself, for that matter. There's no single correct way to do anything, I think. ;D

 

[zeeprogrammer]

Sorry, good point; I'm dragging your thread off-topic with my posts!

Not at all!

I appreciate all the help and tips.

This thread is all about learning...machining...the forum...the members...how a common interest breaks down all kinds of barriers...

This is just such great fun.

 

[vlmarshall]

This is just such great fun.

It IS! I do this stuff for other people all day long, but then come home and stay up late making more metal chips, cruising two forums, and planning what I'm going to do tomorrow!


(Way Off Topic)
I really enjoy MAKING things, and I don't understand why everyone I work with isn't the same way, and doesn't have little projects of their own, aside from the odd "Deck Umbrella post" or "Lawn Mower Trailer Hitch" or other boring thing.

Worse, they always seem to ask, "Whutcha makin', a bomb?"... like that's the only thing a person could possibly be making on their own. Scary, huh?

 

[zeeprogrammer]

I know what you're saying. You start talking about this exciting thing you're doing and you can see their eyes glaze over. Can't blame them though. Just not their interest.

But then there's those (I'm lucky to have a few at work) that are genuinely interested. And that's part of the fun and reward too. And if your family is interested...well...

It's like this forum...it's a good thing we're all separated. Can you imagine us in a room? We'd all be looking looking looking and asking questions and heaping praise...a poor guy wouldn't be able to get to his machines and work!

Okay...so now I'm off topic...better stop before I get all weepy.

 

[Seanol]

Zee,
What about chucking in the milling vise and using the v block under the extended stock? You might have to shim it to get to the right height but it would stop the downward pressure from deflecting the stock. You could also use a clamping set up (like a 52 piece set) and with 123 blocks make a support under the extended stock.

Hope that helps,
Sean

 

[Foozer]

So the busted drill bit...

How far down in the hole did the bit break off at? Curious

A couple of members mentioned the possibility that the down force caused the piston to move down and that I might consider a V-block. One of the eagle-eyed members pointed out that I have one as he'd seen me use it. (A spy!)

I'm just trying to figure out how...

Just a rambling here

Put the fat lady on a diet, clip her at the knee, cut the extra off, or perhaps turn the stock 180 in your 3 jaw and run the fat end down to match the piston dia. If your 3 jaw is good on the run out might just meet the dia. spot on. worst case the dia are a smidgen off, probably not enough to worry about or nothing that a skinny shim wont cure in the V-Block. Clamp that down in the vise and do both operations.

Ya, what vlmarshall said, "I'd turn more of the stock down to the finish diameter, and clamp it with your V-block(s)."

 

[zeeprogrammer]

Hi Sean. Thanks. Your post (as well as others) got me thinking...

What about this...

So the idea is...put the part in the vise on top of the parallels. Slit saw. Force is -x...no -z. (I should install a stop on the -x end to counter the cutting pressure...but I haven't got one or the inclination to make one just yet.)

Then...put that clamping stuff in place...just enough to hold the part up to counter the z force yet enough room to let the drill pass through. Shim to suit.

This way I don't have to remove the part and I can make sure the hole is perpendicular to the slot.

Anything I'm missing?

Couple more questions...is 'chucking in the vise' the same as 'clamping in the vise' or does it really mean put the part in a chuck and then the chuck in the vise?

Also...what is a '52 piece set'? Is that the clamping kit? Like the stuff I show in the pic?



Bob...just saw your post. The bit broke well into the part. No chance of grabbing it and removing it. It's probably only 1/16" or so long but it may as well be 10'.

I thought about turning the part around and turning the other end down...but it seems risky in that I believe I went too far turning it in the first place.

But even if I didn't...in effect it's starting over which I was prepared to do in the first place...and more prepared when I didn't do a satisfactory job turning in the first place.

I have the metal so I'm thinking I'll just start over fresh. I'll keep the part...I have a box of such parts. Memories...and handy fishing weights. Drat...I quit fishing years and years ago.

Thanks Bob. Or is it Robert now. Hey! You're the one that remembered I have a V-block!

 

[Seanol]

Zee,
Sorry about the terminology, I have been searching for a how to on turning an MT3 taper without a taper to copy and have "lathe on the brain.

Your setup is what I was thinking and the clamp set I described is what you have shown.

I would drill the hole before machining the slot so the drill doesn't try to force the slot closed, binding the bit. If you have to slot first I would insert a wood wedge, or shim, in the slot so it can't close up on you.

For small drills I peck drill the hole, i.e. small downfeeds and regular withdrawal of the drill bit. Not all the way out but up enough to stop cutting. One way that works well was in Machine Shop Trade Secrets and that was to set your quill stop a small amount below where you start and drill to it. Then spin it down a little more and repeat.

Good luck and I am following with interest,
Sean

 

[Foozer]

Hi Sean. Thanks. Your post (as well as others) got me thinking...

What about this...

Then...put that clamping stuff in place...just enough to hold the part up to counter the z force yet enough room to let the drill pass through. Shim to suit.

Should work, other end is sitting on bars, free end supported from underneath, sounds like a doable

Bob...just saw your post. The bit broke well into the part. No chance of grabbing it and removing it. It's probably only 1/16" or so long but it may as well be 10'.

was curious if the bit decided to go south when it broke through into the slot, thats the point I have broken more bits at, the gap in a stack up of parts has claimed more than one bit

Thanks Bob. Or is it Robert now. Hey! You're the one that remembered I have a V-block!

Robert, too many Bobs here, OOPS you found the SPY



Robert

 

[zeeprogrammer]

...was curious if the bit decided to go south when it broke through into the slot...

Hi Robert,

No, the bit didn't get as far as the slot...at least there's no hole nor dimple. It was a 3/64 (well close to it...I used a #56 I think) and I think I just poked rather than pecked. That is, it broke just when I was thinking I should pull up and let the chips out.

Geesh...I wonder how long the 'newbie-ness' lasts?

Thanks

 

[Foozer]

Hi Robert,

Geesh...I wonder how long the 'newbie-ness' lasts?

Thanks

Forever, lot of the process,s become easier by virtue of repetition but there is always something challenging over the horizon.

 

[vlmarshall]

Y'know, Zeep, I was thinking about your clamping issue, and I thought I'd mention; the moving jaw on a machine vise pivots a bit, and when you're only clamping a part with one side, it'll close further on the empty side, pinching your part at only one point, in this case, the saw-cut end of your round stock. I know you couldn't have clamped that part in the middle of your vise, but a second piece of equal-size material on the opposite end of the jaws will help even them out and hold better.
Maybe you've already heard it, but I wanted to say it anyway.



Night, all. ;D
-Vernon