2015 POTD Thread Archive

[chevydyl]

so heres another cool thing i did this last week, we were having troubles with the carb on the firebird resto, it had been "professionally" rebuilt, however the car would barely run, and die when put into gear, sprayed starting fluid around the carb baseplate and she revved up.... it had a warped baseplate the throttle shafts rocked like a baby lol.
i started with .5 white delrin, turned to final OD, then drilled, then ground a boring bar and took the walls to about .015" while trying to cut the bushings apart they just broke off, worked out great. the throttle shaft has no play now and glides like butter on a warm bun...lol. I was almost certain it wasnt gonna work when i could see the tool through the wall of the delrin. the carb is a Rochester QuadraJet, the base plate shown was lapped on a thick glass pane, it sealed up great and the car runs good now

 

[Franko]

I use Delrin for a lot of my projects. I love the way it machines.

 

[chevydyl]

it sure does machine nice, leaves a good looking finish as well. i read online someone had used .015 thick teflon sheet, and cut little strips to make these bushings, but i like a full "capture" bushing, this method also does not require drilling, or any other modification, however the bushing kit that we bought from a supplier, contained bronze bushing which you must drill the base plate to use, furthermore, we used that kit in another carb base and the results were....ok, it was not nearly as smooth as the self lubricated Delrin/acetal. im sure the bronze will outlast the delrin though.

 

[Ski]

Have a look at the following posts:
http://www.hobby-machinist.com/thre...in-your-shop-today.14637/page-146#post-272982
http://www.hobby-machinist.com/thre...in-your-shop-today.14637/page-158#post-286120
http://www.hobby-machinist.com/thre...in-your-shop-today.14637/page-163#post-289651

I there is interest I will do a separate post with more details and pictures of the build from beginning to end. Seems a lot of machinist have an interest in forging and casting too.

Please do a detailed post. I was looking for a nice one to build. Is the center section a optional piece? Depending on size needed? What size propane bottle did you use? Ski

 

[Ski]

It was a 14kg LPG tank and cut into three sections so I can reduce the size. Normally I expect to just use the top and bottom section and will make a crucible that suits that size for casting aluminium - which was the primary purpose for building it.
Lining is two layers of 25mm ceramic wool blanket - in the photos I'm using a off cut on top to reduce the exhaust hole size to limit heat loss as the actual hole in the top has been designed as a charge hole for feeding the curcible.
Once it had got up to heat I just turned off the gas and put some more ceramic blanket off cuts on top with a brick to hold them down. Had a peak about 30 minutes into the cool down and the iron was still glowing red.
And yes, end result should me a mini anvil.

I have 3 sections of track cut to size for anvils. I am about to attack with grinder and start shaping them. How durable is the annealled anvil going to be after this?

 

[savarin]

Threw together a quick and dirty hot wire cutter to make some stryo patterns for metal casting. Its powered from an old battery charger,
the cutter is a strand of stainless unraveled from a fishing trace, the support is a length of mild steel set to allow it to spring and tension the wire when it gets hot.
Temperature is controlled by sliding the contact wire up or down the cutter wire.


The pin is set in the base so the foam and card can spin round.
I didnt worry about keeping the rings whole as I could glue them back together


I used a glue bottle that fortuitously was the correct size for the hole, wrapped it in glad bake so the glue wouldnt stick and stacked them together. The elastic bands held the two ends together.


The whole assembly slid out easily.


The hole was aligned nicely but the outside left a bit to be desired so I turned up two wooden mandrels and used the lathe to turn the outside even then sanded smooth.

If all goes well this will be the front of the telescope.

 

[MozamPete]

I have 3 sections of track cut to size for anvils. I am about to attack with grinder and start shaping them. How durable is the annealled anvil going to be after this?

The idea of annealing the rail was just so I could machine it on the mill without burning out too many cutters. Once finished I plan to harden and temper it again before using it. If you are just going to shape it with a grinder then I don't think there would be any advantage in annealing it.

 

[Joe Harlan]

simple modifying of race pistons for a Datsun race engine.

 

[Franko]

Here's some of the things that can go wrong with a bender. Not supporting the bending arm pin caused me to split the parts where I had drilled and tapped holes. Others are just trying to figure out where to put the part in the bender so the bend would be in the right place.

It took me a whole day to bend the three brackets for the gizmo I've been working a week on. Bending was supposed to be the simple part of the job.

This is just the cutoffs. After screwing a bend, I'd cut off the bend and try again on what was left of the piece of material.

 

[Franko]

I got some cheap iron 3" wheels for the lathe stand I'm making for my ordered PM1127. They were swivel wheels, but I'm going to use them as stationary wheels. The axle was 3/8" and bored way whomp-jawed. I chucked them in the lathe, faced the ends and bored them out with a 1/2" end mill for a beefier axle.

The hubs are cast a little off-center, but after my work, the axle holes are now concentric with the rims.