T head engine by Brian

[Sparky_NY]

No, not really. I have the spring loaded T handles (snap gauges) that you measure with a micrometer, but nothing for holes smaller than about 5/8". I do trust my reamers for size, but the chamfer on the end of the reamer is the reason I used the endmill instead. I've been machining for about 13 years now, and at least once a week I find something out that I commit to memory, saying "Huh!!! Won't do that again!!!"

Don't we all ! Seems most of what I have learned over the years comes from trying all the wrong ways first.

[brian Rupnow]

No, not really. I have the spring loaded T handles (snap gauges) that you measure with a micrometer, but nothing for holes smaller than about 5/8". I do trust my reamers for size, but the chamfer on the end of the reamer is the reason I used the endmill instead. I've been machining for about 13 years now, and at least once a week I find something out that I commit to memory, saying "Huh!!! Won't do that again!!!"

[chipmaker4130]

Gotcha. Though it takes more time, boring that on the lathe might have saved the hassle. Do you have small-hole measuring tools?

[brian Rupnow]

I do have collets for my R8 spindle on my mill. However, this was really a lathe job. Both parts were done on the lathe. I do agree that the tailstock on a lathe is a wobbly answer to some of my machining issues.

[chipmaker4130]

How about end-mill holders? If you have neither, you'd be truly amazed at the stability, accuracy and increased tool life they provide. Chatter and wandering caused by using a drill chuck to hold endmills is a primary cause of edge-chipping, etc.

[brian Rupnow]

That would probably be a great idea if I had collets.

[chipmaker4130]

That explains it. Tailstock & chuck, by which I'd guess you mean drill chuck. You'll get a very precise hole if you set it up in your mill with a collet. All small lathes have too much flex in the tailstock ram, not to mention the drill chuck, to get good results with an endmill.

[brian Rupnow]

It was a carbide endmill in a tailstock chuck with the lathe doing 150 rpm in a pre-drilled hole.

[chipmaker4130]

. . .A 3/8" endmill cuts a hole about 0.010" oversize. . .

Not unless you use a long, hss endmill. Kept short, or solid carbide the hole will be on-size or sometimes a tenth or two undersize. Its also good to drill the center out first and sometimes begin the cut at relatively slow RPM if plunging. .010 oversize indicates a bad endmill, collet or machine/technique. If you held the endmill in a drill chuck that alone could account for the oversize hole.

[brian Rupnow]

Today was painting day. I picked up a can of orange Tremclad paint, because that was the only color that I hadn't used already. The fan can be flat back, it's not that important. The aluminum gear covers didn't really need to be painted, but there were enough dings and low spots in them that I filled all the low spots with J.B.Weld yesterday, sanded it smooth this morning and gave them a double coat of aluminum paint. I wish there was a filler that matched the raw aluminum color exactly, but if there is I don't know about it. Now, it seems like I've worked myself out of a job for the time being, so the rest of the day will be spent doing not much---Ahhhh

[mochinist]

Today I machined a fan, and done something dumb. The fan and pulley are silver soldered together, and the hub has a recess for two ball bearings and a spacer. They are in a blind hole, and all of my reamers have a chamfer on the end. To get around having a chamfer in there, I cut the counterbore with a 3/8" endmill. Dumb move. A 3/8" endmill cuts a hole about 0.010" oversize, enough to make the hub go all "wobblycock" on the bearings. My fix is to mount the fan and hub in the 3 jaw chuck, and mount the fan shaft and bearings in the tailstock chuck. Liberally coat o.d. of bearings and spacer with J.B. Weld, then advance the tailstock ram until everything is where it should be linearly. If I've lived a good clean life (Ha-Ha), everything should be aligned when get up tomorrow]

This stuff is a better alternative to JB weld even though the jb weld will work just fine. Good stuff to have around the shop for “repair” jobs. https://www.henkel-adhesives.com/us/...ctite_660.html

[brian Rupnow]

This morning I brought all the drawings up to date and saved them as .pdf files. There are 43 drawings, and some have multiple sheets, so there are about 50 drawings in all. Each component has a detail sheet, and the main overall assembly has parts lists and identifying part numbers and bills of material. I have a bit of finish work to complete on the fan components, but the drawings are complete and included in the package. I sell a complete set of these drawings for $25 Canadian funds, paid to Paypal to [email protected] ---Brian

[The Artful Bodger]

Knowing how to fix a cock up is a mark of the professional!

[brian Rupnow]

Today I machined a fan, and done something dumb. The fan and pulley are silver soldered together, and the hub has a recess for two ball bearings and a spacer. They are in a blind hole, and all of my reamers have a chamfer on the end. To get around having a chamfer in there, I cut the counterbore with a 3/8" endmill. Dumb move. A 3/8" endmill cuts a hole about 0.010" oversize, enough to make the hub go all "wobblycock" on the bearings. My fix is to mount the fan and hub in the 3 jaw chuck, and mount the fan shaft and bearings in the tailstock chuck. Liberally coat o.d. of bearings and spacer with J.B. Weld, then advance the tailstock ram until everything is where it should be linearly. If I've lived a good clean life (Ha-Ha), everything should be aligned when get up tomorrow.

[brian Rupnow]

I bought a Solidweld Tig 185A ac/dc from Messers in Canada. It was economical and seems to work very well.