.60 Crusader WIP

[Seanol]

After seeing what Gain in NM and Maryak have done I thought it would be a greak first project for me to tackle. The series in Home Shop Machinist and is fairly well documented.

I started with the tools I would need for the machining of the parts:

Then I started on the crankcase (or the trial run as I call it):

The crankcase is titanium 6/4 grade and was a bear to machine. Until I used carbide! I tried HSS and ground my tools but they wore out and work hardened the surface quickly. I switched to c6 carbide as that was all I had and it worked! It looks worse in the photo than in real life.

The Ti needed no clean up, only filing of burrs on edges. The bore came out very smooth as did the rear crank cavity. The only rough patch is boring the rear there are lines where I missed the depth slightly. Since the crank bushing goes past this as the thrust face I am not to worried.

The problem I had was I made the snout and drilled the hole to .500. Then I bored it out to .600. When I turned the crankcase around to bore the rear cavity I was unable to get it concentric! I had a dial indicator on it in the 4 jaw and got it between the lines (each one .001) but when I tried a cut longitudinally I found it cutting les that the entire piece. I bored the rear and then sent the boring bar down the crank snout so that both bores were concentric but the outside of the snout is not by a small margin (I notice it!).

Also, when machining the sides in the mill I missed the mark for the mounting tabs so I omitted them. I also had the jaws of the milling vise mark up the rear top so I beveled the top, removing clearance for the cylinder studs! Oh well...

I disconnect the gear train when using the dial indicator so I can turn the chuck over (4 jaw) and it seems that the backlash of the gears makes perfect alignment difficult. Anyone have a better idea?

I have 3 more billets to use so I learned what I needed on this one and should start the next 3 soon. I still need some cast iron for the piston and some tooling (reamers and such) but I am very excited with the start.

I know the project is ambitious and the material difficult but that is why it is my hobby and not my job.

Thanks for looking,
Sean

 

[Maryak]

I disconnect the gear train when using the dial indicator so I can turn the chuck over (4 jaw) and it seems that the backlash of the gears makes perfect alignment difficult. Anyone have a better idea?

Help :-\ I don't understand how backlash in the gears messes up the alignment. Just a thought but maybe your headstock spindle bearings are a little worse for wear, or your carriage/bed are similarly upta. The way the previous owner cared for your machine would suggest it did not have an easy life before you.

Best Regards
Bob

 

[Seanol]

Maryak,
When I disengage the gears I spin the chuck with the dial indicator on the stock. If I go back and forth there seems to be movement on the needle.

My spindle bearings are adjustable, maybe I need to look at that. I can't detect any motion axially or in thrust but I haven't hooked up the dial indicator to that yet.

Looking at the chuck I think I may have had some swarf in the chuck and that may have been part of the problem. Ti seems to make a mess of curly swarf and it gets everywhere!

Thanks again for your help,
Sean

 

[roadrage17]

Similar one to the one im making except its tiny haha , Good luck with it .

Its looking good

Best regards

RR17

 

[Seanol]

I replied in another thread about my 4 jaw chuck but I thought I would include more here.

I adjusted the headstock bearings and still have an issue. I even tried another indicator and same thing.

I am going to look at this a little harder this weekend and see if I can find a solution. Otherwise I don't know how I can turn the snout, bore it to size and rechuck to bore the rear and have it all concentric!

Thanks for looking,
Sean

 

[Seanol]

Got some more done today with a small tragedy.

First the work!
Crankcase assembly line:

Machining blank to size:

Machining snout:

Radius tool and diamond hone:

Set up used to get concentricity with the snout:

Small disaster:

Where I left off today:

I made some headway with my centering issues. I tried every way to mount the indicator to the work and still had issues with about 1.5 to 2 thou runout swapping end for end. While machining the snout I drilled a .295 hole all the way through (drill bit that was handy).

I have a carbide form tool that I got with the lathe. I used my diamond hone (bought at one of the henry homeowner stores) and put a fine edge all the way around and plunged it in with about .225 remaining on the snout. After I had the radius done I turned the snout to .875 (.874 because I measured it hot, not cold, doh!)

I turned the stock over and inserted 2 parallels against the face of the chuck and brought a mt2 taper center into the hole and my mt3 center in the tail stock into the end of the mt2 rear arbor.

Indicating off the center point of the mt2 arbor I was able to get the needle to barely flicker. When I turned on the lathe and brought in the original drill bit it entered the hole and removed no swarf. I think that will work. Since I will be boring the rear crankcase pocket and snout in one chucking I think it should all be good.

The oops moment came when turning the crankcase to size. I was making a small pass (about .005) and the swarf got behind the piece between the front face and the chuck. While the cut was happening I took a screwdriver and tried to remove the offending material and ran into the chuck and the tool. It gouged the work and broke the middle of the lathe tool.

Nothing that is took bad to fix but a near clean shorts moment for sure!

Boring the rear of the crankcase and the snout tomorrow if honey-do's are not in season...

Sean

 

[roadrage17]

Where did u get the drawings for this?

Best regards RR17

 

[Seanol]

Roadrage,
They are in the Home Shop Machinist issues from July/August 2005 to March/April 2006.
There should be back issues available from HSM.
Thanks,
Sean

 

[roadrage17]

Thanks for the prompt reply Sean.

RR17

 

[Seanol]

Today was kinda good, kinda bad. :

I was going to machine the rear of the crankcase I was working on and start my d-bit reamer project.

As I was over confident I drilled through the crankcase with a little more enthusiasm than normal and drilled off center! :-\

As I didn't spot this until I unchucked from the 4 jaw I thought I lost half a days work.
Then it dawned on me, I have a collet chuck and the snout is .875. Perfect!
I turned down the next crankcase snout and spent some time drilling this time and remounted the collet chuck and finished the crankcase. Well, almost. As I was setting up my indexing boring bar I broke the tip. No problem, I will swap sides and... the insert broke in half! :'( :'(

Luckily I had a long, springy boring bar to use. Multiple passes later I have 2 crankcases:
One with a bad bore:

The family:

When I was boring the first case I was concerned about getting depth to size. This time I measured the distance between the work post and the crankcase. With this set I just bored to the tool post and then retract:

Picture of the bore finish:

All in a days work:

Clean up tomorrow and back at it sometime during the week.

See ya,
Sean

 

[roadrage17]

Good job looking nice sean

Best regards RR17

 

[Maryak]

Sean,

Don't get too upset about the bore, from memory of Wareagles thread this bore has bushes. Just make your bushes a tight press fit 0.002"/1" diameter and a final ream after pressing them in; to the crankshaft size. Nobody will ever know and my lips are sealed. ;D

Best Regards
Bob

 

[Seanol]

Bob,
Thanks for the words of encouragement. Without this site I have no mentors to solicit advice so it make this a daunting task.

My biggest worry about the bush was the engine looking funny. I try to be a perfectionist but my lack of skill keeps getting in the way!

I should have searched the forums earlier. I searched high and low on the internet and there was help only a couple of posts down!

This is a new thing for me, two stroke. I have extensive experience with 4 stroke racing engines but nothing at all on two strokes! Do you know if War Eagle ever completed his engine?

Thanks again for the help,
Sean

P.S. I will be rereading your 3cc post again as there are a ton of nuggets in there for me to mull over.

 

[Maryak]

Sean,

I am very happy that our forum is doing its' trick and allowing us all to share our ups and downs.

As far as I know, work got in the way and Wareagle has not finished his Crusader. He's been flat out since Xmas.

When the engine is assembled you wont see the bush at all; or only a small amount such as on the M10 where it matches the OD of the nose.

Best Regards
Bob

 

[Seanol]

Hey guys,
I was able to get a little shop time today but it seemed to be tools to make tools. I made an MT3 arbor for my keyless drill chuck in the lathe and let me tell you, you have to have a plan or you will be swapping centers and chucks all day!

I found out why I was having so much trouble with the 4 jaw chuck.
I don't have a chuck key for it so I have been using a 3/8 ratchet instead. I make sure I get it good and tight. Well, therein lies the rub: I was springing the jaws! :-[

Today I tried to just snug and creep up on the run out instead of tightening it all out. As soon as I loosened a tight jaw I watched the indicator settle down and presto, I had zero zero all around! ;D

This is the stuff you just have experience to learn. What put me on the trail was looking at my 3 jaw chuck key and realizing that the moment arm was quite a bit less...

More this week I hope!

Sean

 

[Seanol]

OK, so Zee finished his so I need to step it up.

Well...At least I am catching up on his wall of shame(learning)! :big:

I tried side milling the crankcase and every time I took a cut the end mill creeped down a little more. I didn't notice until about .100 in.

Not scrap but not to plan so I will keep this one aside for now:

This time I decided to be smart and mill from the top. I carefully touched off and brought my 2 flute Putnam .750 end mill to bear. I made it through one side before the Ti dulled it. I honed it with a diamond stone but after a couple of cuts I got sparks.

Plan B. I have a "Little Hogger". I got through the other side and that went dull as well.
This picture shows the insert. It should be straight across! It is the one in the foreground and came with the set:

I tried some better carbide I found buried in my tool box and it worked great! .010 depth of cut at 360 rpm feeding by hand in the Y axis.

It still did a number on the insert but it is cutting well and no sparks!

So I turned over the piece, carefully measured and finished the side. I made sure I had both to equal depth by using a height indicator on 123 blocks to clear the lathe.

Height is even but I turned the crankcase the wrong way! I have 2 tabs that start at the centerline of the crankcase on opposite sides! :'(

My wall of shame so far with one left to get right:

I found that a large part of my problem was my vise. I am using a sine vise that is screwless. I modified it so I could lock it down in the horizontal position (ask me why... :) and made clamps for it. Unfortunately it is rather tall and the height combined with a lack of footprint really shakes things up!

I have a Grizzly clone of a Kurt pull down vise I am going to work over and use that as it has a much larger footprint and should help rigidity.

Sorry about the cell phone pics as the kids decided to drop test the digital camera and they won :

My plan going forward is to side mill using the "little hogger" creeping up to depth. Once that is done I will see where I stand. If I mess up the last crankcase I will bite the bullet and get some aluminum round stock and make it the way it was intended. Ti is some tough stuff but I can get it for cents a pound so I am not out anything major (other than alot of used up tooling!)

Thanks for looking,
Sean

 

[zeeprogrammer]

OK, so Zee finished his so I need to step it up.
Well...At least I am catching up on his wall of shame(learning)!

Hey! It's not that big a wall...is it?

before the Ti dulled it.
and that went dull as well.
It still did a number on the insert but it is cutting well and no sparks!

I'd been wondering about this. What signs tell you a cutter is getting dull? Sound? Sparks? Shape of chip? What was the 'number' - I mean describe the bruising.

My wall of shame so far...

'Wall of Learning'...'Learning'. It's more positive. I need to work on that habit too.

I modified it so I could lock it down in the horizontal position (ask me why... :)

Why? :big: Seriously...what do you mean by horizontal? Or do you mean it's locked down to prevent the top part from being pulled up?

Thanks for posting. It's an interesting thread.

 

[Seanol]

Zee,
The wall is getting there...

My first indication is when I take the same depth of cut (D.O.C.) and you can almost see the surface work hardening. It will get very shiny and start to look polished. This is the cutter skating over the surface. Also the chip will start to get orange and then it will start sparking

At this point (I only let it happen on one pass) I look at the tip and you can see the tip worn down. I lost about 1/16th of an inch on that tip in about 20 minutes. The new insert is much higher grade and is able to take a larger d.o.c. Where this comes in handy is heat removal. The larger the chip (within reason) the more heat leaves with the chip, the less in the work piece. Ti has terrible heat transfer properties so if you get it hot it hardens the surface. Your next cut needs to go below this skin.

I bought a 5" screwless sine vise because I thought the convenience would be nice. The problem was with the brackets tightened down it would still tilt up on a heavy cut. Luckily the piece I was working on was scrap anyway.

I ran a bolt through the back (let me tell you, that stuff is HARD the first couple of thousandths!) and threaded it to hold it down. I made the clamps you see to mount it as I was unable to drill any holes or mill a slot on the side (3 more dull end mills :)

I have a Grizzly 4" Kurt copy and the reason I went away from this is because I could never get the vise to stop lifting the work, as much as .015! The first indication was the parallels becoming loose. I put an indicator on the work and tightened down the vise and you could see the deflection!I thought I could tighten the angle jaw internally but it never worked. I took it apart last night and found the set screw is only a lock for the screw underneath it!

I am going to go over the vise today and clean and adjust, measure and tweak until I am happy. A bad vise makes everything a chore.

Thanks for the interest,
Sean

 

[zeeprogrammer]

and you can almost see the surface work hardening. It will get very shiny and start to look polished.

The first indication was the parallels becoming loose.

I almost want to try it (hardening) so I can see what it looks like.

Thanks for the discussion on heat transfer. Very helpful.

Ah the parallels. I had the experience of one of the parallels vibrating out because it was loose and the end mill catching it and trying to throw it across the room. That generated some tips on using foam, or foam peanuts to keep the parallels in place. It was also suggested to hammer the part down as the vise is tightened so it stays on top. My problem with the hammering though is room and possible marring.

Thanks Sean.

 

[Seanol]

Zee,
What I have found is that if the part is square it will sit down on a set of parallels with out hammering using a screwless vise. Usually when the parallels are loose it is the movable jaw parallel and this is because the fixed jaw squares up the work and the movable tries to keep that square relationship. If the work faces are not parallel the work will locate on the fixed jaw and the part will lift to maintain square on the movable jaw.

This is just my observation, not a science by any means! ;D

What I have been doing is tapping the work down(I use a dead blow plastic hammer. Others use a small brass or lead hammer to get into tight spots) lightly on the parallels and if it moves I use a pusher on the movable jaw and remove the loose parallel. Then I take light cuts to square the material so I can use both parallels again. I also use strapping from pallets as a parallel holder. I cut them in many lengths and bend them over on themselves. They are springy and hold the parallels firmly against the jaws.

Hope that helps,
Sean

P.S. I have a 2.375 by about .750 thick piece of 6/4 Ti stock left if you want it. Would make a cool flywheel except for the light weight! :big:
You could use it on a brassy babe. Imagine a little motor with a big honking flywheel. Paint it and everyone would wonder how a little motor could turn that big wheel! PM me am addy and I will get it sent off.