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Old 10-29-2015, 08:59 AM   #1
Truckedup
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Default Home machinist help

I'm building a dual Triumph engine LSR bike and lots of custom parts as you can imagine.
The drive linking the two engines is 530 chain and driving of the rear engine is a Harley primary chain to Harley 5 speed...
To adapt all this stuff it's easiest for me to turn down the OD of a Triumph engine sprocket and then bore out the center of generic 530 sprockets and the Harley primary engine sprocket. The result will be pressed together and then welded...
I have a WW2 Logan lathe and kinda know how to use it. In the past I have done similar jobs but the parts were not as hardened as these sprockets...
Can this be done will carbide lathe tools?
The budget will not allow me to have this done at at machine shops because of cost and they simply don't want to be bothered...
If any of you want to be bother just let me know Thanks

This photo shows more or less what the drive will look like...

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Old 10-29-2015, 09:09 AM   #2
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Default Re: Home machinist help

yes on carbide. You should shop around for a shop, like you said some of them don't want to be bothered, and some will get into it. Share your story about what your doing with the shop you may find the reasonable machining help you need. I have.
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Old 10-29-2015, 09:15 AM   #3
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Default Re: Home machinist help

Build pictures as you go will be appreciated .
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Old 10-29-2015, 09:47 AM   #4
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Default Re: Home machinist help

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Originally Posted by joe49 View Post
yes on carbide. You should shop around for a shop, like you said some of them don't want to be bothered, and some will get into it. Share your story about what your doing with the shop you may find the reasonable machining help you need. I have.
I live in a rural area but there's maybe a dozen machine shops within a half hour drive...I get the set cost story...then estimates of 300 bucks. I know their time is money and they are probably busy so don't need a small job...

I have a modern quick change tool holder and right and left facing and turning tools with replaceable tips. And several boring bars...time to smole some tools...

I will start a thread when I have a series of photos but right my pile looks like this


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Old 10-29-2015, 10:12 AM   #5
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Default Re: Home machinist help

Slow speed,lots of cutting oil and slowly plunge a thinned down cut off tool. I did a Sportster drive sprocket for a project that never got off the ground on an old South bend belt drive lathe. Worked but took quite awhile.

Or you could use two to get what ya need but boring one to size and cutting the OD of the other to fit. Regardless of method used to cut be very careful with set up so that concentricity to the drive is maintained. If not she'll vibrate like a dog shittin' razor blades at high speeds. Ask me how I figured that out.
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Old 10-29-2015, 10:12 AM   #6
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Default Re: Home machinist help

If it won't cut with the carbide, you will still have a circular mark where the carbide tried to cut .Use that for your lay-out line ,cut the hole with plasma then put it back in the lathe and true it up with a hand held die grinder.
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Old 10-29-2015, 11:40 AM   #7
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Default Re: Home machinist help

Can you post a picture of the sprockets please?
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Old 10-29-2015, 12:39 PM   #8
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Default Re: Home machinist help

I adapted a Harley center to a Triplex outer... twice. Sort of opposite of what you're doing. What I'd recommend is instead of working from the outside and turning the teeth off the Triumph sprocket, I'd use a cut off type tool and plunge into the side of the sprocket as close to the center as possible. Less cutting that way. Also, when clamping the 530 sprocket in the jaws to cut out the center wrap some steel around the outside to help center the sprocket and protect the teeth. I used some exhaust pipe and it worked great. FYI, you can get machinable center 530 sprockets from McMaster Carr. 530 is the same as ANSI 50. Here's a 19 tooth but there are many other options. http://www.mcmaster.com/#2299k47/=zkv5sf

This is a shot of my second attempt after finding a machinable bore Triplex sprocket so I didn't have to weld two sprockets together. Fortunately all I had to do was put a taper bore in the center. A splined Triump center would be much more difficult.

[/URL]

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Old 10-29-2015, 12:47 PM   #9
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Default Re: Home machinist help

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Can you post a picture of the sprockets please?
mine look like this....Harley FL engine sprocket that needs it bore enlarged .



Triumph engine sprocket below needing it's OD reduced to fit inside the Harley sprocket... There might be other ways to do this of course but I need to think of ways to do it with the tools and skills I have...

Triumph sprocket
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Old 10-29-2015, 03:44 PM   #10
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Default Re: Home machinist help

Maybe a dumb question, but have you tried these guys?

http://www.martinsprocket.com/produc...sion/sprockets
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Old 10-29-2015, 05:08 PM   #11
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Default Re: Home machinist help

I think a compensating sprocket may make things a little easier for you if the tooth count you need (23-24) is available. The center is bored accurately and you'll just need to remove the cam lobes. May save ya some time.

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Old 10-29-2015, 05:30 PM   #12
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Default Re: Home machinist help

You could try to heat the piece cherry red and try to cool it as slowly as possible. Machine it and flame harden it again with a torch.

Sometimes the engineers at work comes up with a last minute change to a part that is already hardened. Then we heat it 500degrees C and let it cool in the owen over night. Machine it and reharden it.
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Old 10-29-2015, 07:18 PM   #13
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You could try to heat the piece cherry red and try to cool it as slowly as possible. Machine it and flame harden it again with a torch.

Sometimes the engineers at work comes up with a last minute change to a part that is already hardened. Then we heat it 500degrees C and let it cool in the owen over night. Machine it and reharden it.
I do backyard heating treating....Why didn't I think of that? The bike runs less than a three hours a year for testing and track time, the sprocket would last a long even left unhardened..

And the compensating sprocket would be easier...

Ok ,thanks
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Old 10-29-2015, 07:52 PM   #14
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Default Re: Home machinist help

FWIW my professional machinist bud gets nearly all his shops carbide insert tooling via Ebay. It was a hoot to watch him explain that to the Sandvik rep who went away with no sale. Auctions, business liquidations, and estate sales are great for pigging out on tooling, tools, and tool boxes. Lots of quality stuff out there for cheep if you do your homework. I agree with joe49. There are still friendly small shops around and what OP is asking for is easy work.
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Old 10-29-2015, 08:45 PM   #15
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Default Re: Home machinist help

trucked,
Carbide should cut that material without a problem. Some of the sprockets I've worked with are harder in the tooth area and softer towards their center or hub - selective heat treat.
A trick that sometimes comes in handy for chucking a round piece with a weird outer profile like a gear or a sprocket is to use short pieces of round stock that drop into the valley between the teeth so the jaws register on the round stock instead of part of a tooth. Sometimes, depending on the tooth count, if it won't line up with a 3 jaw it will line up with a 4 jaw. Or vice-a verse-a .

Geo.
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Old 10-30-2015, 05:38 AM   #16
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Default Re: Home machinist help

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Originally Posted by old.wrench View Post
trucked,
Carbide should cut that material without a problem. Some of the sprockets I've worked with are harder in the tooth area and softer towards their center or hub - selective heat treat.
A trick that sometimes comes in handy for chucking a round piece with a weird outer profile like a gear or a sprocket is to use short pieces of round stock that drop into the valley between the teeth so the jaws register on the round stock instead of part of a tooth. Sometimes, depending on the tooth count, if it won't line up with a 3 jaw it will line up with a 4 jaw. Or vice-a verse-a .

Geo.
Good adaptation of using pins for measuring Sporty cam gears for selective fit.
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Old 10-30-2015, 06:25 AM   #17
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Default Re: Home machinist help

Can someone show me the proper tool type for cutting the center from a sprocket ? Or use a boring bar starting from the center hole?
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Old 10-30-2015, 11:23 AM   #18
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Can someone show me the proper tool type for cutting the center from a sprocket ? Or use a boring bar starting from the center hole?
Not sure how proper it is but I'd start with a hole saw mounted in the tailstock and then finish it with a boring bar.
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Old 10-30-2015, 11:52 AM   #19
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Default Re: Home machinist help

I used a cemented carbide cut off tool modified by grinding it down. I used the carriage feed and plunged it slow;y w/lots of oil. Those sprockets aren't as hard as you think they are. Stringy,gummy like chips from 304 stainless. Plunge a little back out,oil up and plunge again until done. Slow spindle speed,say 70-100 RPM. Then used a standard boring bar for finish/size.

Started out like this then ground for clearance.
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Old 10-30-2015, 12:03 PM   #20
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Those sprockets aren't as hard as you think they are.
Agree. I filleted the center of this motorcycle sprocket with nothing more than a shank-mounted stone and a drill press. I didn't even have a fixture, I just held it in my hands and let the round stone find its own center.



Given the limited use yours will see (and the knowledge that sportbikes don't use just steel sprockets), how about something made from aluminum? Do alu front sprockies exist?
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