The Machine Work Thread

[Vanapplebomb]

[Brian_e]

[chrisflstf]

[nsracing]

Those are all the wrong tools for working on valves -

Don't treat your precision parts like that. If you don't have the proper tools, leave them alone.

At minimum, you need a lathe to do the back cut. Accuracy is key - if your valves are all different shapes, how do you expect them to flow properly? Those angles have to be similar valve to valve.

The best way is just buy you a proper valve grinder and seat grinder. They are all over Ebay -

[Vanapplebomb]

The back cut on a valve isn’t super critical. I say go for it. Try it on a junk valve first. As long as you keep the grinder clamped steady so the angle doesn't drift while it’s running, you will be fine. The runout of the chuck on the drill press shouldn’t be more than 5 thou or so. Heck, it’s probably as good or better than the antique black and decker valve grinding machines that are all over the place.
_________________
1800 Type 4 Berrien 295

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

[nsracing]

The most worn out valve grinder will still be way better than any handheld grinder of any brand.

But hey - try the handheld grind back cut and show pics here. Maybe we can see how good one's dexterity is. Should be fun to watch.

Maybe post a video -

[chrisflstf]

Here u go. Not hand held, actually clamped good in the jaws. No way for the dremel, lol. I may experiment swapping it around some , before i test it out. And i will need to figure out measuring the cut angle as the adaptor has a fair amount of play in the chuck. But i can compensate, if i know the cut angle.

[Vanapplebomb]

Nice work. I am sure that will work well. May be a little slow, but should work fine. Valve grinders are quicker and are easier to get a consistent width of the back cut. However, with a bit of time and care, you can get good results with the set up you have.

I actually know a guy who reground his worn out R8 spindle taper in his Bridgeport mill by clamping a die grinder in his mill vice, angled the head to match the taper, then with the mill and die grinder running, fed the grinder into the spindle. Turned out great. He checked it with bluing and a good R8 arbor. Even blue coverage everywhere. Took his spindle runout from about 0.001” inches to about 0.0002. Not perfect, but probably better concentricity than most collets on the market today.

Just goes to show that you can get good results with basic tools, a little ingenuity, and patients.
_________________
1800 Type 4 Berrien 295

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

[chrisflstf]

My version of adding a DRO, lol.

[modok]

Your valve grinder setup is very far from optimum, but there are some good ideas in there too.
I like the idea of the valve held vertically, and using the angle meter.

[nsracing]

I don't think that angle attachment is gonna be fast enough to do grinding w/ that iddy-biddy stone. Maybe use a Dremel tool instead?

I can see a toolpost grinder bolted to the table and just swing it over to the valve to remove material. Maybe a 2-inch wheel?

For grinding, the chucking head only needs to spin very slow. But the grinder wheel needs to be spinning pretty fast if it is small diameter.

[chrisflstf]

Thanks for the input. I was wondering about the speeds. Ive made a couple changes, so just waiting for some valves to try out

[Vanapplebomb]

[volk263]

He are some pics of my Rung Fu RF-31 mill that I use to cut a case for bigger cylinders and to deck the case.

[chrisflstf]

Well, My experiment to back cut valves didn’t go well. The stone does not leave a very smooth finish. I think its wobble in the spindle of the stone attachment tool
( right angle drill adaptor). My 30 degree angle seems right on tho

Cut on left, virgin on right

So next stop – machine stop. But hey, don’t know what will work until you try

[Brian_e]

[modok]

[jpaull]

[volk263]

Cylinder bores come out good. You have to keep the runout in the spindle bearings checked and adjust the cutters according. Yes one hold down on each side is plenty. The scale is on the back side of the X axis. The Rong Fu mill comes with the mounting holes tapped for this brand DRO it is a simple bolt on

.

[chrisflstf]

Where do you buy those giant 1 x 2 x 3 blocks?