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A friend stopped in on Sunday with a dirt bike carb that had a float needle seat in rough shape. Kawasaki says non-replaceable. A lathe says otherwise. Here's the carb with the seat pulled (using a tap) And the seat, with the needle, threads cut by the tap used to pull it Some nice brass...

There was mention of wanting to build a parting tool holder that uses broken hacksaw blades, so I thought I'd post my version in a place a little easier to see. I used a dovetail cutter to make slanted grooves to retain the hacksaw blade against the vertical surface, and made a notch to clear...

Just a cautionary tale. Turned out well enough, but it was nearly a disaster. I was milling the light end of a crankshaft off, to form the crankshaft weight. The crankshaft was setup in a fixture used to turn the crank pin, so the crank bearing journal was in a reamed hole in the face of a...

3d CAD is amazing sometimes, but sometimes it makes me start from unreasonable assumptions which then makes me question my math. Right now, it's throwing off my estimation skills by being so far out of the ballpark I must have messed up with my calculator. I can easily determine the...

I learned something important about dial indicators this weekend while dialing in a horizontal bore on my horizontal mill. http://www.longislandindicator.com/p139.html "We had a belligerent customer whose dial indicator wasn't returning to zero when he used it upside down. We told him...

Can someone point me in the right direction for valve design for a 4 stroke IC engine? interested in valve diameter, port diameter, and valve lift. Generalities and rules of thumb for my first engine design would be fine I think but I'd like to try to make some informed decisions instead of...

1) That wasn't the slitting saw I wanted, it was a wood cutting saw that ended up in that cabinet drawer. Oops. I figure it burned the teeth off immediately, and then I pushed harder. 2) My cheap vise doesn't hold very well, the fixed jaw stretches the bolts and flexes away. 3) a 1/3 absent...

Way back when I became interested in radio control models, I dreamed about designing, building, and flying my own engine. At that time I was pretty good with a hacksaw and a file, but that's all I had, so that dream sat and waited for 15 years. Now I'm equipped with a 10" lathe and an...

I know that using a leather or mechanic's glove is dangerous, but I think using the blue nitrile or vinyl gloves should be fairly safe. I've had tonnes of these gloves fall apart when I ask them to stand up to automotive mechanic's abuse, and the other day a long curl snagged and tore one glove...

I've got a Craftex (Busy Bee) B2227L that's got a nice geared head, but not a quick change threading gearbox or anything, just the usual changable gear train for threading. Soon I'm going to need to cut a left hand acme thread, so I decided it was time to get going on making this thing move the...

On every lathe I've used (granted, only 3 of them) all of different brands and sizes, the tailstock travel is never long enough so that if one end of my work is held in the chuck, and the other end in the tailstock live center, I can't cut the entire length from center to chuck in one pass. I...

I've got something to stick on my lathe that's longer than fits between centers. If I mount it with a steady at the tailstock end, how can I ensure I've got the work adjusted in the steady so that it's running on the centerline of the lathe and not flexed off center? Dial indicator doesn't work...

I need to make some type of valve to hold small air pressure (less than 5 psi) and be operable by a standard size RC servo. Having serious trouble coming up with ideas that aren’t high drag. I could use a cam-lock type clamp on a piece of tubing, but I dislike crimping the tubing, it kind of...

I was running a really sweetly running RC gas engine the other day that I've got hanging on my favorite model airplane. Did a great flight, landed, killed the engine with my ignition cut switch on the transmitter, checked the battery, topped up the fuel, and went to restart it. Flipped my arm...

I did a small glow two stroke rebuild a few months ago, and things went well till I realized it was losing power as it heated up. I tore it down, and found that my press fit of the wrist pin in the aluminum piston was no longer a press fit at running temps and was wearing a groove in the...

I recently made a new piston and liner for an RC engine to practice making the tapered cylinder fits, and it runs great! Now I think it's time to try an entire engine. I've grabbed the plans for the Bollaero 1.8, but I'm wondering what the consensus is for the best way to make the cylinder bore...

I'm finishing up my two stroke reconstruction, seems to run great! I'll make another thread with details. My question was, I messed up the wrist pin hole in the piston a little. I drilled with a numbered drill bit the same size as my wrist pin, forgetting that I needed to go undersize and ream...

I don't have an edge finder, and didn't want to wait to get one to start my project. I discovered this a while ago when I was using a Taig, and it worked well today. Take some thin uniform paper (thermal receipt paper works well), and place it between the jaws of your milling vise to...

Is there a formula to figure out how wide your exhaust port can be in a two stroke before you need to have a bridge? And is there a guideline on how big that bridge should be?

I'm trying my hand at refurbishing a glow RC airplane engine. There's a fair sized scratch that seems to be letting out too much compression when the thing is warmed up and expanded to running size. It's an aluminum piston, with a nickel plated brass liner, non-ringed. It appears I'm going to...