2018 POTD Thread Archive

[Ray C]

Made a couple involute tooth miter gears. It's outlined here. https://www.hobby-machinist.com/threads/miter-gear-cutting.69779/





Ray

 

[Cadillac]

I wish I can say I did this in a day. I only get a hour or two maybe a day. This is my first arbor of this precision. I did between centers. I found planning out ever step of the process needs to be well thought out. I won't get into the mistakes. dialing in the taper took awhile because I cut a test piece and blued a hub. I adjusted till it was near perfect. The taper is nice and tight and I feel theirs no need for mounting nut on arbor. When hub is mounted there is zero runout on wheel mounting surface. Flange of hub has .0002 of wobble. I think that should be ok ?
I've read that balancing a wheel under 8" is not necessary. I received a Anderson static balancer about two years ago from a friend that got it from a uncle that passed and he knew it was for machinist so he had given to me. I really had no specific uses for it but I knew what it was. After I bought my surface grinder it was all coming together. Now I have a real use for this puppy.

 

[Ray C]

I wish I can say I did this in a day. I only get a hour or two maybe a day. This is my first arbor of this precision. I did between centers. I found planning out ever step of the process needs to be well thought out. I won't get into the mistakes. dialing in the taper took awhile because I cut a test piece and blued a hub. I adjusted till it was near perfect. The taper is nice and tight and I feel theirs no need for mounting nut on arbor. When hub is mounted there is zero runout on wheel mounting surface. Flange of hub has .0002 of wobble. I think that should be ok ?View attachment 267790
I've read that balancing a wheel under 8" is not necessary. I received a Anderson static balancer about two years ago from a friend that got it from a uncle that passed and he knew it was for machinist so he had given to me. I really had no specific uses for it but I knew what it was. After I bought my surface grinder it was all coming together. Now I have a real use for this puppy.
View attachment 267792

Nice, useful item. Amazing that making a simple shaft with a simple taper -is not really simple!

FYI: The only wheel I ever had fly apart on me was a 6" that was out of balance.


Ray

 

[hman]

By the way, really like those Scotch-brite wheels on a grinder. I have them in difference “grits”, the fine bring out a really nice finish in a few seconds.

+1 on the value of Scotch-brite wheels! I had a 1" belt/5" disk sander in each of my shops (Oregon and Arizona) and converted both of the disk sanders to hold Scotch-brites. I've probably used them more than any other tool in the shop - cleaned/polished up both lathe and mill projects, as well as derustification of raw materials, etc.

 

[hman]

<snip>
If I am splicing two wires together, I will strip about 3/4" -1" of insulation and slop a 2" length of heat shrink over one wire. I then tightly twist the two wires together with the two ends facing each other, working the twist to compact and smooth it and trimming any excess wire. I then solder the splice, tape it with electrical tap, and slide the heat shrink over the splice to lock the tape.
<snip>
In more than thirty years, I have never had a soldered trailer connection fail. This includes multiple boat trailers where the connections are immersed in water.

I've recently (re)discovered "marine grade" heat shrink. It's standard heat shrink tubing with a thin coating of hot melt glue inside. During the shrink process, the hot melt liquefies and seals off ANY gaps. When cool, it very positively prevents water intrusion. Sort of "gilding the lily" over and above your method. But really good insurance.

 

[Cadillac]

I've recently (re)discovered "marine grade" heat shrink. It's standard heat shrink tubing with a thin coating of hot melt glue inside. During the shrink process, the hot melt liquefies and seals off ANY gaps. When cool, it very positively prevents water intrusion. Sort of "gilding the lily" over and above your method. But really good insurance.

In my field corrosion to electrical connections is a major problem. I only use crimps with the heat shrink already installed on crimp. My supplier has crimps that have Di electric grease inside shrink which is just another way combating corrosion.

 

[extropic]

I bought a used Blackhawk 4 Ton hydraulic cylinder that needed some TLC so I made some bits to get it done.


Blackhawk RC-540 Cylinder, as received.

Most of the pictures are "after the fact reconstructions" because I didn't originally plan to post.

The cylinder is the type using accessories which attach with 3/4 NPT threads (rather than the push-on type). First I needed to make a puller to remove the threaded sleeve from the end of the piston. I used a black Iron Pipe Coupling and modified a Pipe Plug by tapping 5/16-18 thru.


Coupling and Plug after tapping


Puller, ready to use.

Looks like I forgot to take a picture of the threaded sleeve removed. My bad.


Next, I needed a spanner wrench to remove the Piston Retainer. I've rebuilt a few similar cylinders and the retainers have all been easy to remove without a special tool but, this one was too tight to budge. My mill is still out of service so I decided to use an abrasive disk (AD) on my table saw to do the "machining". I used a square 5C collet block to hold a 1" expanding mandrel to hold the tube that would become the wrench. I set the saw fence to just clear the AD, started with the AD set low and made repeated passes, flipping the collet block and raising the AD until I had the "teeth" real close. I finished it to size and deburred with files.


The Wrench is shown rotated so a "tooth" is visible. The Piston Retainer at right.


I reversed the Wrench on the expanding mandrel to drill through for the drive bar (screwdriver shank).


Ready to install the Piston Retainer.

Last, I made some (4) thread protectors to keep the cylinder threads from getting beat up. I have another 4 ton kit that included a plastic thread protector that fits too loosely (falls off with the slightest provocation) and it's been a chronic source of aggravation for me when using that tool.
NO MORE!

The stock I used was 2" OD x 1.375" ID 6061 tube. I had to buy the stock because I don't have one of those magic "scrap" collections, that I read about so often, that allow EVERYTHING to be made from "scrap" on hand. I chucked up a 6" long piece. First op was to bore ID to about 1.450" for about 60% thread depth. Second op chamfer ID to 1.55". Third op was to tap (the thread is 1.500-16 and I happened to have a tap). I threaded only deep enough to cover the threads on the Cylinder Body. Fourth op was turn OD to 1.70 (seemed about right). Fifth op was set cutoff at 1.10" long and start cut to about .06" deep, break edge (chamfer) with file, and knurl with "scissor type", 3 roller hand held knurler (is that a word?). After knurl, finish the cutoff. Rinse and repeat.


Ready to install a Thread Protector.

I bought the knurling tool from (you know) and hadn't used it before. I chose to use it this time because it had nice course, straight knurls installed. The second and fourth parts came out OK but the first and third "multi-tracked'. The customer (myself) has accepted the discrepancies but gave the machinist a stern verbal reprimand. I'll have to try to figure out how to use this knurler with more consistent results. I suspect that tightening the hinge action may help but, we'll see.


Handy Knurler


Quite a range of results (not pictured in order of manufacture).


Blackhawk RC-540 Cylinder refurbished.

That's all folks. Thanks for looking.

 

[RJSakowski]

I've recently (re)discovered "marine grade" heat shrink. It's standard heat shrink tubing with a thin coating of hot melt glue inside. During the shrink process, the hot melt liquefies and seals off ANY gaps. When cool, it very positively prevents water intrusion. Sort of "gilding the lily" over and above your method. But really good insurance.

I bought an assortment of that type of heat shrink a few decades back. It was a collection of different sizes up to 1/2" in 4" lengths. It worked OK but as I recall, it was fairly expensive and not easily found.

I haven't personally tried this but I would expect that you could accomplish the same effect by applying a dab of hot melt glue to the joint before sliding the heat shrink over the joint. This can easily be done by applying a coating with a glue stick immediately after soldering the joint.

Thanks for the reminder John. I just threw a glue stick in my emergency tool kit.

 

[Ianagos]

Made my first large fixture plate today. Still working ou the kinks in my programming but seems to be working well.

 

[GreatOldOne]

Not a make, but a do - I finally got round to replacing the starter motor on Vikki my kit car. And I swapped out the fan belt that had started to perish.

What a faff getting the old starter out. The original Bosch OEM starter has a body that has a bigger diameter than the housing that bolts up to the gearbox / engine bell, making it next to impossible to get a socket and extension bar on it. Eve with the extra room I have by taking the side panels of the engine bay. The new starter is the same diameter all the way down, so it’s easy to fit.

All done now. She turns over and starts immediately now, every time you push the starter button. She was a bit lazy on the old one, and every now and then it wouldn’t turn over at all... which could be a bit embarrassing.