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Offline Terry in Australia

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Terry's boring weekend.
« on: February 15, 2009, 04:22:41 AM »
Well the bushfires are slowly coming under control, but seeing how all my favorite ride roads go through the affected areas, I decided against going for a ride today.

Also, the authorities are asking that "sightseers" stay away from the area to avoid getting in the way of the firemen and other emergency workers, and also, the locals are angry that there has been some looting, so are threatening to shoot anyone acting suspiciously. I'd hate to be the bloke who stopped on the side of the road to have a pee, or to give a Koala a drink of water, and got shot by a jumpy local, ha ha!

So instead, I started to bore out Al Harper's CB550 cylinders to accept his new 61mm big bore kit. Like I've mentioned elsewhere, the kit is marked "605cc", but in fact it's about 592cc. Oh well, I guess every little bit counts. Here are some pics:

1. Cylinder block set up on my old "Repco" boring machine that I "inherited" from my cousin, it's probably 50 years old but still works fine, and has bored just about every type and make of small engine ever built.



2. First cylinder done. I need to remove 2.4mm and I only take 0.125mm (.005 in) cuts, so the difference equates to close enough to 20 passes with the boring bar, or at least one hour per cylinder. If you were wondering why boring is so expensive, now you know.



3. Well I took this pic at 5.30 pm, it was 30 deg C in my garage and I'd just spilled a pint of Kerosene on my pants, so I still need to do one more cylinder.



More to follow in a day or two! Cheers, Terry. ;D

 
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So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

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Offline bwaller

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Re: Terry's boring weekend.
« Reply #1 on: February 15, 2009, 04:39:48 AM »
Don't light a match Terry!

Good work... and I hope you get your roads back soon.

Friggin thieves, I quess nowhere is exempt huh?

Offline jtb

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Re: Terry's boring weekend.
« Reply #2 on: February 15, 2009, 07:41:13 AM »
Nice work, Terry.  Glad you're OK.
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Offline Jim F

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Re: Terry's boring weekend.
« Reply #3 on: February 15, 2009, 07:41:32 AM »
Looks like very good work Terry
Glad you and the family are safe from the fires
I hope they catch the people that did this and put them in the fire for punishment
(alive)
Why only .005 per pass? Because the boring machine is so old?
seems like a long day

Jim

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Offline OldSchool_IsCool

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Re: Terry's boring weekend.
« Reply #4 on: February 15, 2009, 07:57:46 AM »
Are you saying you look suspicious when you pee??  :D :D :D  Maybe it's the aroma of Kerosene!  Guess if I came across someone pissing Kerosene in a wild fire zone, I'd be jumpy too!

Glad you're OK.  And nice work too!!
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Offline 754

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Re: Terry's boring weekend.
« Reply #5 on: February 15, 2009, 08:39:29 AM »
It looks suspiscious when you only cut .005 per pass.. :D
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Offline Alan F.

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Re: Terry's boring weekend.
« Reply #6 on: February 15, 2009, 08:40:45 AM »
The sleeves are made of?   Cast iron maybe?   Pretty tough to machine, so .005" cuts will leave a nice surface quality without generating too much heat.  Have you ever tried to smooth a busted thumbnail with a coarse file?  Finer cuts will leave better results than taking a large cut too quickly.  

I've got a mini-mill and a mini-lathe, I know a just little about small cuts and slow feedrates.

Offline cb750fbomb

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Re: Terry's boring weekend.
« Reply #7 on: February 15, 2009, 08:59:29 AM »
Looking forward to more pics, Terry and good luck with those fires. Glad to see your safe.
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Offline 754

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Re: Terry's boring weekend.
« Reply #8 on: February 15, 2009, 09:35:46 AM »
Lack of rigidity in smaller tools often leads to chatter.

The boring bar looks to be a stout machine,  often, it is the tool sharpening though, that causes the chatter/heating during the cut.
Maker of the WELDLESS 750 Frame Kit
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Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Terry in Australia

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Re: Terry's boring weekend.
« Reply #9 on: February 15, 2009, 12:23:47 PM »
Thanks guys, I can take larger cuts but I'm a little "over-cautious" after muffing a couple of cylinders when I was teaching myself how to use the machine.

Also, with .005 cuts, there's little requirement for a lot of finish honing at the end, those pics are of the cylinders before honing, they're almost good enough to use as they are. Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline Trevor from Warragul

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Re: Terry's boring weekend.
« Reply #10 on: February 15, 2009, 03:05:31 PM »
Hi Terry,

Do you have a boring bar small enough to handle a 350/4 block?

Trevor
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Offline moham

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Re: Terry's boring weekend.
« Reply #11 on: February 15, 2009, 04:41:24 PM »
Have you ever tried to smooth a busted thumbnail with a coarse file?

I haven't yet but I'm going to right now...my Sunday's planned!
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Terry's boring weekend.
« Reply #12 on: February 15, 2009, 06:18:23 PM »
Pissing kerosene?! You musta run outta Makers, ha 
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Terry in Australia

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Re: Terry's boring weekend.
« Reply #13 on: February 15, 2009, 08:58:55 PM »
Hi Terry,

Do you have a boring bar small enough to handle a 350/4 block?

Trevor
Glen Waverley

G'Day Trev, yeah mate, mine came from a Suzuki dealership in Bairnsdale, and will do anything from 50cc mini bikes, to my 76mm Wiseco 1170cc kit for my GS1000 engine, and my cousin even made a jig to mount the boring head directly onto his 1928 Dodge "Fast Four" to take his 4 inch cylinders out to first oversize many years ago. Cheers, Terry. ;D

Pissing kerosene?! You musta run outta Makers, ha 

Yeah mate, I'm drinking el-cheapo "rot gut" at the moment, all the MM and Chivas I got for Christmas seems to have "evaporated" under the hot Aussie sun? Funny thing is the cheap stuff is "evaporating" at a remarkably similar rate! ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline aussie

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Re: Terry's boring weekend.
« Reply #14 on: February 16, 2009, 02:35:22 AM »
Gidday Terry
Do those sleeves have a lip on top? as they seem really thick.  If they dont, looks like you could go even bigger with the slugs ;D

Offline Terry in Australia

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Re: Terry's boring weekend.
« Reply #15 on: February 16, 2009, 02:39:29 AM »
G'Day Wayne, yeah mate, they do have a big lip on top, there's not much metal left in the sleeves now, ha ha! Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline Trevor from Warragul

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Re: Terry's boring weekend.
« Reply #16 on: February 16, 2009, 03:14:37 AM »
Thanks Terry,

I'll keep you in mind for when I get hold of another standard block.  I have two sets of NOS 3rd oversize pistons/rings, but the mob who did the boring job stuffed it right up.  I like the idea of the block being bored to size without a final hone as there's no chance of it being oversize (1 pass of the hone is fine, 2 passes is too much, 3 passes & the cylinder is stuffed).  I ended up fitting a 2nd hand standard block with matching pistons.  Better than the screwed up block but still not perfect..
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1976 Moto Morini 3 1/2 Sport
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Offline Terry in Australia

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Re: Terry's boring weekend.
« Reply #17 on: February 16, 2009, 06:07:47 PM »
Thanks Terry,

I'll keep you in mind for when I get hold of another standard block.  I have two sets of NOS 3rd oversize pistons/rings, but the mob who did the boring job stuffed it right up.  I like the idea of the block being bored to size without a final hone as there's no chance of it being oversize (1 pass of the hone is fine, 2 passes is too much, 3 passes & the cylinder is stuffed).  I ended up fitting a 2nd hand standard block with matching pistons.  Better than the screwed up block but still not perfect..

No worries mate, who stuffed up your rebore? Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

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Re: Terry's boring weekend.
« Reply #18 on: February 16, 2009, 06:25:21 PM »
How much is a "stuffed up"?

An answer in mm is fine.

Is that 0.005 on the bore diameter, depth of cut, or feed per revolution.  ::)




What kind of boring tools do you use?  On the machines I designed we would use carbide insert boring bars, one for rough, one for finish. Each had an insert designed specifically for the task and Material. Much more then O.005 inches.


Old Machinist taught me bore for straightness, ream for size, hone for finish.

With modern tooling the second and third steps are generally not needed. Although we set up the boneheads in Milwaukee with a hone to finish their connecting rods. 

Offline valvolux

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Re: Terry's boring weekend.
« Reply #19 on: February 16, 2009, 09:00:49 PM »
apt subject line terry. At an hour a cylinder, boring sound boring.
glad everyone's vouching your good work, chat to ya later in the week.
Emailed this to ya, but maybe ya learned mates might want to see my new ally tank and seat.
all the best, al  ;)

« Last Edit: February 16, 2009, 09:02:25 PM by valvolux »
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Offline Trevor from Warragul

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Re: Terry's boring weekend.
« Reply #20 on: February 17, 2009, 02:31:01 AM »
It was a few years back.  I took it to "Parts & Pieces".  They no longer exist.  "Stuffed up" means a plug that oils up & is kaput within 100 kilometres.  When you see the size of a 350/4 piston you realize that the boring is critical - there's just not that much room for error.
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1976 Moto Morini 3 1/2 Sport
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Offline david 750f

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Re: Terry's boring weekend.
« Reply #21 on: February 17, 2009, 02:55:37 AM »
markcb750, boring is much more accurate than reaming. Reamers can wear...just an old toolmaker rambling.......
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Markcb750

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Re: Terry's boring weekend.
« Reply #22 on: February 17, 2009, 04:32:37 AM »
markcb750, boring is much more accurate than reaming. Reamers can wear...just an old toolmaker rambling.......

From one old Machinist to another;
On production work for precise holes, reams will beat bores for sizing.  Particularly with long bores as single tool tip can wear significantly, resulting in a tapered hole. The ream will cut the whole length at once to the accuracy of the tool.  I have used many reams that are adjustable. To account for wear.  We also only used the ream to remove about 0.0015" on the diameter.


Reams are much better minimizing hole size differences due to to variances in the material of the hole to be bored.


Many production techniques use some or all my old Machinists advice.  But as I said, good modern boring bars can both rough and finish the bore. Once a good spindle is attached to a good slide, and the part is secure, and the tool holder is pit well, its all up to the boring bar and the cutting edge.  Well it is really up to money; each boring bar can cost $400, a good inset $10


FYI I am not recommending a reaming process for boring cylinders in a repair shop.  I am curious as to what kind of tooling is applied, as proper tooling can make a huge difference in rate of material removal and final size consistency.

Mostly I just want to bullsh*t a little.

Offline 754

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Re: Terry's boring weekend.
« Reply #23 on: February 17, 2009, 07:55:36 AM »
Terry would hate boring 883s to 1200, we take out 500 thou. :o
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Lost quite a few CB 750's along the way

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Re: Terry's boring weekend.
« Reply #24 on: February 17, 2009, 09:16:13 AM »
Terry would hate boring 883s to 1200, we take out 500 thou. :o

With the right equipment & tooling that is about 4 passes... ::)

Offline 754

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Re: Terry's boring weekend.
« Reply #25 on: February 17, 2009, 09:37:54 AM »
I bore them on the lathe, then the engine shop hones out the last few thou..

sure are thick liners though..
Maker of the WELDLESS 750 Frame Kit
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Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

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Re: Terry's boring weekend.
« Reply #26 on: February 17, 2009, 01:14:36 PM »
I bore them on the lathe, then the engine shop hones out the last few thou..

sure are thick liners though..

What size lathe do you have!

Do you counter balance the load or depend on the hone to clean up?

Out of round due to unbalance bearing loading would be significant.

Offline 754

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Re: Terry's boring weekend.
« Reply #27 on: February 17, 2009, 05:15:20 PM »
Sportster barrels are fairly symetrical.

I use a 16 inch lathe that weighs 3700 lbs, so it can take a fair amount of imbalance, if it was vibrating I would add counter weight.

I leave 3 or 4 thou for the engone shop to hone, they are honed with torque plates.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

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Re: Terry's boring weekend.
« Reply #28 on: February 17, 2009, 07:59:14 PM »
Sportster barrels are fairly symetrical.




I was envisioning a cb four being bored on a lathe, not a easy thing to swing.

Offline 754

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Re: Terry's boring weekend.
« Reply #29 on: February 17, 2009, 08:15:29 PM »
Thpught you moght be thinking that, think you would need  at least a 28 incher..

Easy to throw it (4 cyl) on a vertical mill in a pinch.
Maker of the WELDLESS 750 Frame Kit
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Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Terry in Australia

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Re: Terry's boring weekend.
« Reply #30 on: February 17, 2009, 10:01:21 PM »
apt subject line terry. At an hour a cylinder, boring sound boring.
glad everyone's vouching your good work, chat to ya later in the week.
Emailed this to ya, but maybe ya learned mates might want to see my new ally tank and seat.
all the best, al  ;)



G'Day Mate, hey that looks great! Has it arrived yet? Cheers, Terry. ;D


How much is a "stuffed up"?

An answer in mm is fine.

Is that 0.005 on the bore diameter, depth of cut, or feed per revolution.  ::)

What kind of boring tools do you use?  On the machines I designed we would use carbide insert boring bars, one for rough, one for finish. Each had an insert designed specifically for the task and Material. Much more then O.005 inches.

Old Machinist taught me bore for straightness, ream for size, hone for finish.

With modern tooling the second and third steps are generally not needed. Although we set up the boneheads in Milwaukee with a hone to finish their connecting rods. 

G'Day Mark, I'm not sure if you were asking me or Morini the "stuffed up" question, but if it was directed at me, my first attempt to bore my 70mm Suzuki GS1000 cylinders to 72mm ended up with a sloppy .004" clearance on #1 cylinder.

I know that "a poor tradesman blames his tools", but the "depth of cut" micrometer that came with my boring bar looks like it was used at one time as a hammer, so if you have a good one there that you'd like to sell, or know where I can buy one, please let me know, at the moment I'm using my digital vernier which appears to be very accurate, but a bit tricky, as it doesn't "hold" the tool like the OEM mike does.   

.004" is still within spec, but I couldn't bring myself to use them, but recently I scored a set of "almost new" 73mm (1085cc) MTC forged pistons, so when I get time I'll bore the cylinders out to suit them, although I'll stop a few thou short and use my recently aquired Ammco 500 micrometer adjustable 4 stone hone to finish them.

The .005 is depth of cut. The tools are, I believe, carbide inserts sweated onto the tool holder, they hold their edge really well which is good, as I tried to resharpen an old one with a chip taken out of it on my bench grinder, and it was damn near impossible.

I've never tried to ream out a cylinder, but it makes good sense, and I guess in a way the Ammco 4 stone hone is about as close as the average bike shop would get to a reamer anyway? It's a pity it's too big for this engine, I ran it for a couple of passes in the GS1000 cylinder, and was very impressed with the smooth, even finish.

The Ammco hone was in fantastic condition (thank you EBay!) and came in the original steel case with all the accessories, and even had all the original literature, including an advert for a conrod finishing honing machine, which I thought would be a pretty cool old tool, if I can find one?

Oh, and Frank, the 1200 conversion kit for the 883 is so cheap I don't know why you'd bother, but my 17" swing lathe with it's 1 metre bed would likely handle the "roughing" cut's, I've bored a couple of CB750 sleeves in the 3 jaw chuck, then (after shrinking them back into the cylinder block) finished them on the boring bar, which seemed to work quite well. But to be honest, I'd rather start with a 1200 Sporty and buy the 1400 kit anyway............  ;)

Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline crazypj

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Re: Terry's boring weekend.
« Reply #31 on: February 17, 2009, 10:20:24 PM »
Sportster barrels are fairly symetrical.




I was envisioning a cb four being bored on a lathe, not a easy thing to swing.

 That's easy, set it up on angle plate on  cross slide and use boring bar between centers.
 Shrunk in sleeves wouldn't allow reaming, too much torque needed.
 Engine machining (on motorcycles) isn't like normal machine shop processes.
FWIW,
 The 'lip' on the top of cylinder liner is called  a flange, the bit that sticks out the bottom is a spigot
 Terry, you don't try and use micrometer to set tool tip to dead nuts size, you do a scratch cut, measure the bore and then use the tool tip as your 'zero' position. You only need to know if bore mic is measuring radius or diameter (basically, ignore all the sleeve scale readings and use thimble scale only)

PJ
« Last Edit: February 17, 2009, 10:24:42 PM by crazypj »
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Offline Terry in Australia

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Re: Terry's boring weekend.
« Reply #32 on: February 18, 2009, 04:54:21 AM »

Terry, you don't try and use micrometer to set tool tip to dead nuts size, you do a scratch cut, measure the bore and then use the tool tip as your 'zero' position. You only need to know if bore mic is measuring radius or diameter (basically, ignore all the sleeve scale readings and use thimble scale only)

PJ


Thanks PJ, that's actually what I did, I did a "scratch cut", then backed the adjuster screw on the cutting tool out .005 for each pass.

The mike is totally stuffed, so I used the digital vernier, it seems to be very accurate, but a little tricky as it doesn't "hold" the tool like the boring bars mike. Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline 754

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Re: Terry's boring weekend.
« Reply #33 on: February 18, 2009, 07:26:48 AM »
Terry, you need a certain stone to grind carbide, the ones i use are always green. carbide will eat a normal stone.

Terry, the first 883 we took to 1200 was back in around 93. Here an 883 is a lot cheaper to insure (and we been known to streetrace){also cheaper overall to mod the 883 than to buy a 1200, plus the sleeper factor}. Anyway the Sporty owner also raced a cb750.
So at the time, you could not buy drop in pistons, HD sold a pair of stock 80 ci pistons & a template. The template
 was to modify the head from a bathtub to hemi shape like an 80ci.
 Anyway, we bored the cyl out, opened the chamber, cut part of the Stock baffles out, removed the aircleaner element. So  stock pipes carb, aircleaner cover.. ran 12.7 first time out! (just in case anyone wonders why I am not so sure that a CB 750 will beat most Harleys) Cost me a lot more to get my 750 to do that >:(

PJ, I would skip the bar between centres and hold a boring head in the chuck for that method. It takes a long time to centre bores though, mill is quicker.

Terry, if you do pop sleeves out to rough out, press them in a tube (a few ways to hold them), less chance of cracking or distortion.
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Markcb750

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Re: Terry's boring weekend.
« Reply #34 on: February 19, 2009, 05:02:12 AM »
Email I recieved, thanks David for trying not to hurt my delicate sensibilities. Mark

--- On Wed, 2/18/09, David

    From: David
    Subject: Cb750 boring
    To: "vt532002@yahoo.com" <vt532002@yahoo.com>
    Date: Wednesday, February 18, 2009, 7:08 PM

    I did want to make this public on the SOHC forum but I just checked the
    Machinery Handbook and even the best reamer only holds a .0005 thou tolerance,
    my worst jig boring machine holds a tenth. If I do it myself I can hold a
    tolerance +or- 0000 thou.



Jig boring, or not, doesn't matter...

Don't know where the conditions are but .0005 is one half a thousands of an inch...pretty dam good if you are trying to size a hole with out piddling around with settings on a boring bar.  Pretty sure if the trick builders here could make the four bores in a 750 cylinder with in +/- 0.0005" of each other they would be able to build the engine with confidence

Do not know what bores you are talking about holding 0.0000 size on with a boring bar but my experience tells me the boring bar will create a nice hole, but never hold size particularly on long bores with out significant tinkering from hole to hole.  Even on a really nice Devlieg.(how is that for old!)



Dill, Bore, and ream. will create a very consistent series of holes. if half a thousands over or under is a problem, an adjustable ream or hone can be used to fine tune. I have delivered systems to the aircraft and nuclear industries where we held +/- 0.0001 inch on final sizing.

FYI
Drilling removes excess material quickly.
Boring locates the hole correctly; drill bits tend to wander and drill at an angle particular at long length/diameter ratios
ream finishes to size without a lot of operator intervention.


A good ream will also produce a better surface finish for some applications.  As I said, modern machines and boring bars with super hard inserts negate this old machinists rule, particularly in job shop situations.

The biggest problem I had with machinists finishing bearing bores and cylinder bores is not leaving the final cut depth correct, leaving too little material for the cutting edge to bite into and either oversizing the hole, or leaving a very rough bore due to chatter as the cutting edge bites then deflects out of the material.  This could be why Terry uses such a low feed depth, this insures he is slowly approaching that final pass but who knows could be because that old boring machine just will not stand up to a greater cut...I think you see the input skill has by knowing you can hold closer tolerance then others, some guys just have the skills, some don't.

For CNC operations we now have probes, computers and multiple ways to automatically offset the boring bar tip to finish the hole.  I don't know anyone outside the airframe business still consistently reaming holes.  Boeing bought 2 Machines from us in the 90's to develop single pass hole drilling and sizing using high speed tools and high pressure coolant, I assume the experiments worked, but who knows.  I left that industry 10 years ago.






Mark
Thanks for allowing me to think about the past a while this morning.  We made some great machines.