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Cast Iron Issues.

I order a chunk of cast iron from my supplier. The outside did not look great.

CastIronOutside.JPG

After a bit of machining, this is what was there.
CastIronOutside85.JPG

It did not cleanup after removing over 10 mm.

CastIronOutside78.JPG

The supplier was happy to credit it and I got a new piece. Only issue is it was 140 mm in diameter and I needed 82mm. So there goes a bit of time.

I have had this before over a 3 foot piece. I rejected the whole bit. Best to check the material before machining.
 

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Discussion Starter #622
Marsh; It’s time for you to machine a wooden pattern for your own use. You should be able to find an iron foundry that would be happy to pour these parts for you. There should be enough information in the thread to give you a hand in the project. If you need any other help let me know; the scariest part of the project is just getting started.
JT
 

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Mill Upgrade

I have a CNC knee and I do my cylinder boring using the quill. The one problem I have is the quill travel is only 100mm. If a cylinder is longer, I have to raise the table manually to complete the cut. The problem is, the manual feed does not normally make the same depth of cut as auto.


Here is what I used.
OldBoringBar.JPG


It has been on my project list to motorise the bed so I can do longer barrels for many years. Anyway making the new Maico barrel (which is 150 mm long) galvanised me into action. On Friday, at lunch time I decided to get on with it.


I used a scale to measure the torque required and it was 7 kg on 220 mm to turn the bed handle. I scrounged around my box of bits (projects I had in mind but not started as yet) and there was a good size stepper with 450oz/inch. At around 6 to 1 it may just be enough.



A call to the local automation shop and by 4 pm I had two new pulleys and a belt with a ratio of 6:1 and a center to center distance of 140 mm.


A couple of skims on the table's bits and I managed to fit a 6 mm plate to the machine which will hold the stepper and still retain the hand lever operation.
TimingBelts.JPG


A bit more digging in the project box and I had a Gecko stepper. A bit more digging and a suitable transformer bridge and cap was found to supply around 35 volts at 4 amp.


So far so good, off to the local electronics shop and about $40 later, I had all the switches and NE555 timer chip.


A couple of bread board mock-ups gave the required results, up, down step and continuous and well as fast and slow speed.

555.JPG Control.JPG


All done and dusted, the table moves.


A few weeks ago I was at a friends place and he was getting rid of odd stuff and for some reason I bought another boring heads for $50. I guess it was because it was made in Japan. It had a strange thread fitting onto the NT40 adapter and I didn't think much of it.

NewBoringHead.JPG


Anyway I pulled out a small boring head I had bought from Alliexpress specifically for cylinders about a year ago and blow me down, it fitted the new shank thread.





NewHead.JPG NT40.JPG



Things were looking good.


Back to the cast iron scrap box yielded a reject bit of sleeve material. Already the right length and with a hole in the middle. After a bit of machining, the new extension was ready.

Extension.JPG


So my new boring bar is ready to go. This time I will clamp the quill and use the table to do the complete movement. I just need to make sure everything is square.




NewBoringBar.JPG



Not a bad weekend of projects.


Lastly, I had a home made lathe holder with a 5 mm circular tip in it from a previous job. Being a bit lazy, I used this to turn down the cast iron. It made a fantastic job of the finish. Best I have ever had.


I'll make a new holder for the new boring bar and give it a try.
Tip.JPG
 

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Discussion Starter #624
Rite on Mate

Marsh; although rather inconvenient, your boring system is fine as long as the head is square with the table. Your finish honing would clean up any inconsistency. We have the same types of boring heads for a couple of our vertical J-head machines; I’ve never attempted a cylinder bore with this system. You may find some ideas on U-tube. U-tube is a wonderful resource if you sort out the BS & bad information.

You are a very ambitious person who I’d be proud to work within our shop, WOW. Your circular boring bit idea is also a good one as long as there isn’t a chatter problem.
Sorry I’m lecturing; I was once a machine shop instructor & you shifted me into teaching mode.

Please keep us up with your work; Myself & a lot of other readers are gaining some valuable information. I’d expect that others will soon chime in with comments on your project.

Maybe your project will twist your arm & convince you to look around for a Kwik Way cylinder boring machine. I realize that there are some other brands of machines but IMO, Kwik Way is the best.
If you purchased a machine; the word would slowly get around. You’d be surprised how quickly your investment would pay for itself.

This kind of input is what I’ve always hoped to see in the thread, thanks guys.
JT
:Cheers:
 

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Sorry I’m lecturing; I was once a machine shop instructor & you shifted me into teaching mode.
Your replies did make me scratch my head a while back, but now I understand. I'd be happy to be your student.

I've been looking for a boring machine for a while but here in Christchurch New Zealand, they are scarce. On that line I phoned Buchanans foundry about sleeve casting. R. Buchanans Foundry was established in 1878 in Christchurch, by Robert Buchanan. The reply I got was, 'After the earthquake, noone in the council was prepared to sign off on the new building permits, so all the machinery, furnaces castings etc went to the scrap dealers'. I wanted to cry. All the knowledge and history gone.

Such are times today.

The other issue is I really dont have any more space. I'm not sure where I even going to put the new second hand cylindrical grinder I have just bought. This is for doing motorcycle front shock tubes.

Cheers Wallace
 

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Wallace, looking at your cylinder wear photo a couple of pages back, there's an alternative way to address this besides John's perfectly good method of giving the piston better support via a bridge in the port.

Obviously the problem is that given the crank rotation, the piston cocks over on the downstroke so that the skirt wants to jam itself into the port. You could lessen this effect a bit with a longer rod (so the piston cocks a little less hard), but another idea you might consider is to turn the whole cylinder around (exhaust towards the back of the bike). Now, since the crank rotation is unchanged, the piston (which you also turn around) skirt is now cocking against the nice smooth sleeve area below the exhaust port. G. Jennings did this on an engine, as have a couple of outboarders. Getting at the problem by this method would be a lot more trouble than sleeving, since you have to re-route the exhaust, do some carving and filling of the port-entries in the crankcase, and relocate various items, so like a lot of other alterations it's a lot easier to do on an outboard motor than a bike, but it is an alternative . . .

Interesting lathe tool . . .
 

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I've seen that set-up done on a Banshee where the did the mods to the case and cyl. bottom end to flip the cyl. around...carb in the front and exhaust out the back of the frame, in which is a performance advantage being the pipe is straight instead of the curved bend to clear the front frame rails. Of course like Smitty said, you need to move the piston 180 degrees to match the exhaust port.
 

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Discussion Starter #629
Some good ideas are starting to show up; when turning the cylinders around there might be some offset cylinder bore locations to deal with.
At times I’ve wondered about turning the cylinder & engine upside down? Reason; when we ran the racing Karts on alcohol & a centrifugal clutch the fuel would accumulate in the crankcase. In order to shut down the engine we would give a quick lift on the Kart’s front end causing the fuel to quickly rush up hill, killing the engine without shutting off the ignition.
Any idea's? :Dope:
 

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Hi Smitty

Sorry I didn't get a notification of your post!!

Some recent progress.

My new boring bar was a great success. The round cutter did have a bit of chatter. With the boring head, my tools had the tips on the wrong side unless I reversed the spindle direction. I made a cutter from an old HSS cutter and what a finish. HSS_Tip.JPG
I cleaned up the bore in 0.02 mm.

Hone.JPG

New sleeve
Cylinder.JPG
 

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longer rod (so the piston cocks a little less hard), but another idea you might consider is to turn the whole cylinder around (exhaust towards the back of the bike).
The rod is already long 132 mm with a 70 mm stroke. The YZ rod is 130 mm. John's solution looks great and done in more recent models. I'm busy with that upgrade now. Just have to finish fixing the cylinder.

Cylinder_Repair.JPG
 

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Discussion Starter #632
The cylinder is a mess; how did it break? .02mm is a little close for a final bore. I usually bore to piston size & then hone the clearance. I don’t worry about the bore diameter as much now that we have the vertical hone. What kind of hone do you use? If you can step up to the expense; Sunnen is the best we’ve found. The deluxe model isn’t necessary. The Sunnen is rigid enough that it doesn’t catch in the ports as badly as other brands
If you’re interested; start a side business, you seem more than qualified. A good way to pick up some extra $$
 

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" The round cutter did have a bit of chatter. With the boring head"

Being in the automotive field, when cutting, machining brake rotors..They had a "round type" cutter bit that they offered for a speedy type- cut once at the high speed and your done.
I've had a couple that had the same issue that you're talking about.
using the round bit v.s. the triangular bit, left an amazing smooth finish in a single pass at a fast pass instead of a rough cut at a fast pass and light cut at a slow pass.

however, there were a few that I had the similar issue with the chatter. Maybe resonance with the thickness or dampening surface.
 

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Discussion Starter #634
A standard CNC feed rate in my shop is +.004” per revolution per cutter tooth; you have control of your down feed so if the cutter radius is much larger than the feed rate, the cut will always be smooth. Excessive tool contact causes the tool chatter.
It’s easy to do the math; cutter depth of cut & feed rate. = contact area. A larger than necessary cutter radius causes the chatter.
 

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If you’re interested; start a side business, you seem more than qualified. A good way to pick up some extra $$
The problem with boring is any mistake is costly. I had to make a new sleeve for the Rotax as I messed up the original bore. There is 5 hrs gone.

I only do rebores if I work on the complete motor for others and my own stuff.

I'll need to check my boring feed rate but it may be as slow as .0015 " per rev.

This is what I have for the bigger bores. PS I find using it dry the best.


The Maico was ported for 10K, far too high. Vibrated like hell, loosened the base bolts and cracked off the lug. All welded up now so onto the re-machining today.
 

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On my lathe, the 5 mm round aluminum cutter is fantastic. Leave a very good finish. As the tool has many edges, it lasts a while.
 

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Discussion Starter #637
You’ve got a 1500 lisle hone; they work pretty well EXCEPT, the stones are glued on & sometimes they will snag a port & snap a stone off.. Truth be told sleeving is very tricky work. We never get paid for our efforts. We have quite a pile of rejects & mistakes. I’m sure that LAS & Advanced also have a pile or two.
Over time percentages will improve for you.

At least you’ve got the guts to dive in & do it
 

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>> snap a stone

Been there, done that. I have hot glued the stones on and run a few extra
beads on the edges to make it a bit safer. Works well now. Are these interchangeable with the Sunnen hones.

I wish there was a smaller one in this style. I have the other lisle hone (16000) for small bores but it is not as nice as this one. (15000)

Cheers Wallace
 

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Discussion Starter #639
The 2 brands are not interchangeable. I purchased my Sunnen Hand held hone used for $165.00. This is the same hone head as the one for the MB series horizontal con rod machine. We use the stone sets which are designed for splined shafts. Faster more accurate stock removal.





You can usually pick up an MB machine used for a little more than $1500.00. The cost usually depends with the tooling which goes along with it.
 

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Why is there such a long 'lead in' on cylinder sleeves ? My Maico has about 25 mm of narrowed section with is still withing the overall barrel length. So the last 25m of the sleeve is about 0.2 mm away from the barrel.

I would have preferred that the sleeve is parallel all the way down for maximum rigidity.
 
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