The Machine Work Thread

[Clatter]

^^^A thing of beauty right there…^^^

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Bus Motor Build

What’s That Noise?!?

[chrisflstf]

So the waisted shank is done to improve elasticity of the stud? The other day I measured my 8mm studs, only to learn they arent 8mm on the shank. Now i know why

[Vanapplebomb]

The waisted shank improves fatigue strength. Basically, you narrow the shank until it is equal to or below the equivalent stress area of the bolt. For an M10x1.5 thread, that area is 58mm^2, which is equivalent to a maximum diameter of 8.6mm.

In the case of your 8mm stud, if 1.25mm pitch, the stress area is 36.6mm^2. That works out to a maximum diameter of 6.8mm for a waisted shank stud.

You can to a degree control how much a fastener elongates for a given load. Alternatively, you can also maintain a clamp load within a specific range with varying elongations. There are a lot of tricks that can be played with fasteners.

If they are just shy of 8mm, it is only because they need a slightly smaller diameter to roll the threads on the ends. The material displaces and pushes up. If you start right at 8mm, there is nowhere for the material to go when rolled. These are not waisted shank fasteners.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[chrisflstf]

8mm is .315 " My 8mm studs, Bugpack chrome moly measure .280" on the shank. Roughly same diameter as the minor root diameter. So these are simply regular rolled threads, not a waisted shank type

Interesting info, thx

[Vanapplebomb]

Shouldered valve guides made of continuous cast C86300 manganese bronze… which really should be called a brass due to the high zinc content. Should hold up really well with hard chromed stems. For raw stainless I may try and use C673, which is similar, not quite so hard, has a little more silicon, and machines easier. C86300 is surprisingly really though stuff. Currently these are just drilled about 10 thou under sized. Final reaming will be done in the head.

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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[Vanapplebomb]

A tip for those who want to trim cylinder bases to reduce deck height, or make custom length cylinders;

Use a large bull nose live center to support the end. If the bottom edge of the cylinder is as cast and not machined, face the bottom of the cylinder to give a nice seat for the bull nose live center so that the cylinder runs true.

These are old used cylinders with are being shortened, and will be overboard to the next size.

I prefer the old iron. It definitely seems harder than the new import cylinders. It cuts quite differently. Hard to describe, but if you have ever cut both… you know what I mean.

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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[RWK]

This is another way to do it, less cost then bull nose center, but you have to have one for each cyl. size.
Set up a dial indicator for length control, or DROs

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73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530

[chrisflstf]

I would have thought that the other end of the cylinder is easier to machine. No?

[Brian_e]

[Vanapplebomb]

Brian is absolutely correct. Also, the head end is thicker, so I feel better about clamping that end with the chuck.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[madmike]

Got my 92mm Cheers,Mike

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'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[Vanapplebomb]

Very nice Mike! Did you just make up a few for various sized cylinders?
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[RickS]

Yeah, but mine is shiny!

[madmike]

No my local Machinist buddy did it , just the one size so far, In hate buggin him,he never charges me anything so I try to do one thing at a time Cheers,Mike
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'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[mark tucker]

eye took old forged V8 pistions, cut off the head then stuck them in my lathe to make the cylinder holders & head centering jigs. why throw away perfectly good aluminum that a chevy guy dystroyed...I also made steering wheel addapton for my bug out of a ford forged 351 oe piston. polished up and never corrodes.

[nsracing]

I just use large flat piece of aluminum and center-drill it. The plate just pushes on the cylinder without loading the sides. No need to worry about different sizes.

[Vanapplebomb]

If I didn’t have a large bull nose live center, I would probably make up some mandrels from scrap aluminum for the end, like the kind you guys have.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[Vanapplebomb]

[Vanapplebomb]

Not really machine work, but useful nonetheless. Any time I run a used flywheel, I sleeve the sealing surface.

I use Timken Redi-Sleeves. They are a light press fit stainless sleeve that is 0.25mm thick, so you can use the stock seals. The sealing surface is cylindrical ground to RA10-20 micro-inches, or about 0.25-0.50 micrometers.

This is an online PDF from Timkens sealing products.

https://www.timken.com/wp-content/uploads/2020/02/National-Indust-Seals-Catalog_7707.pdf

A lot of people make the mistake of polishing sealing surfaces, which is the old school way of doing things, but the ideal surface roughness is actually more corse than you may expect.

There is a flange on one side that is used to push on the sleeve with the installation tool that comes with it. The installation tool looks like a cup. Just set the tool on the flange and tap on the sleeve. The flange peals away like a pop top lid, leaving the sleeve behind.

I use an anaerobic sleeve retainer, not to retain the sleeve, but to seal up any imperfections on the flywheel that may allow oil to weep out between the flywheel and sleeve.

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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[chrisflstf]

Are those the same for type iv and type 1? Part number?