Quantcast

Yet Another Webster Begins

Help Support HMEM:

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
Just an update. Dropped back to do the valve cages. Interruptions from tropical storm Isaias and the normal amount of fixing crap around the house. Next is to make the real valves. Had them inside the house, so I posed them on my keyboard with the test valve.

TestValve_2Cages.jpg
 

werowance

Well-Known Member
HMEM Supporter
Joined
Sep 2, 2011
Messages
1,000
Reaction score
238
Bob, the valve and cages look much cleaner and nicer than mine. id say yours will have no problem starting and running. just use the seat cutting tool when done, dab a little blue on the brass where the valve hits the seat and twirl the tool by hand and just make a small cut by hand until the blue is gone and you have a brass line showing all the way around the seat. i thought you had to have a wide seat like in a chevy 350 3 angle valve grind job or something but Brian R told me the smaller the seat surface the easier it was to get it to seal. and that prooved to be correct. i guess a 350 is putting a lot more compression than the webster is lol.
 

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
I think I'm going to try the method in Brian's post that I saved. He just puts the valve into the cage with some lapping compound and then twirls it by hand. I'll see how that looks.
 

Brian Rupnow

Design Engineer
Project of the Month Winner
Joined
May 23, 2008
Messages
12,401
Reaction score
4,978
Location
Barrie, Ontario, Canada
Don't try my method of lapping until after the valve guide is pressed and/or Loctited into place. They will distort a minute amount, and that amount will be enough to let compression escape. Do the valve lapping after the valve cage/guide is in place and the fuel/exhaust admission holes have been drilled.
 

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
Don't try my method of lapping until after the valve guide is pressed and/or Loctited into place. They will distort a minute amount, and that amount will be enough to let compression escape. Do the valve lapping after the valve cage/guide is in place and the fuel/exhaust admission holes have been drilled.
Thanks, Brian. I didn't get that from the thread I copied.
 

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
Gosh, it has been a long time since I updated. I'm stuck on the silliest of parts - the springs. I'd made one or two before this, but never grappled with how much smaller do you need to make the diameter of the spring so that it doesn't end up too big. I've made four versions of the one light wire spring; three too big and one too small. The too big springs seemed to expand 1/16" diameter - from the 3/16 form to 1/4" when I released them or if I heat treated them on the form. So I wound one on a 1/8" form. It hardly expanded at all.

All along I had this idea that if wrapped the wire tightly on a form and then clamped the wire in place with screws, it would be the fix. So I took a piece of 3/16" drill rod, cross-drilled it and tapped it for two #2-56 screws. After the heat treatment, I took it out and it opened up to close to 1/4", too.

Spring-4th.jpg


The only reason to make the springs precisely to size is because the valve retainers are 1/4" diameter with a 3/16" part that goes into the spring. The 1/4" valve retainers fall into the spring and can't work properly. I could make the retainer 3/8" with a 1/4" nub and I don't think it would make a darned bit of difference, but I've been trying to make it like the prints. I think I move on to that today.

Aside from that, the valve cages are pressed in, the valves lapped, and I've been working on other parts.
 

awake

Well-Known Member
HMEM Supporter
Joined
Sep 4, 2019
Messages
883
Reaction score
315
Location
North Carolina
Bob, you mention heat-treating - what type of wire are you using?

For my Webster, I made my first-ever springs following the original Webster plans, using music wire of the size called for there. With the music wire, no heat treating was involved. I describe the process here: Introducing ... the "Steel Webster" (post #49). Unfortunately, I apparently did not write down the size of the arbor I used, but I can measure it when I get back home.
 

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
I'm using music wire - I bought what will be a lifetime's supply of .015 wire on another project and made a couple of springs.

I've been going by this one tutorial by a camera technician:

He says he puts his springs in an oven at 450F for an hour and then lets it cool slowly.
 

awake

Well-Known Member
HMEM Supporter
Joined
Sep 4, 2019
Messages
883
Reaction score
315
Location
North Carolina
Bob, I measured the mandrel I used - it is .155". I used this mandrel for both the intake spring, using 7 turns of .013" music wire, and for the exhaust spring, using 9 turns of .022" music wire - both of these as called for in the Webster plans. I was pleasantly surprised by how well they turned out, since this was my first experience with making springs.

As noted in my build log, I made and used a simple "gripper" to guide and keep tension on the wire and set the lathe up to the closest tpi for the resulting spring. A couple of turns by hand to establish a flat beginning, then engaged the half nuts, let it turn the 7 or 9 turns, disengaged, and a couple of more turns to establish a flat ending. It helped tremendously that my lathe goes down to 30 rpm at its low end - much faster and I would have had difficulty controlling it. (If I didn't have the low speed, I would have turned the spindle by handle.)
 

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
I like several things about that approach. Certainly neater looking than mine; the gripper takes the place of the needle nose pliers I was using, and setting the lathe up to thread guarantees good spacing. Drilling a hole for the wire at the start never occurred to me. I had considered using my lathe to cut a groove in the tool of the right thread pitch and laying the wire in the groove. 7 turns in 5/8" long is 11 TPI. That would not have the couple of tightly spaced turns you have.

My small mandrel (the spring that didn't expand and is therefore too small) was the 3/16 rod I have turned down to .135 (I called it 1/8" above - that's wrong). That number wasn't completely PFA; I figured that the 3/16" expanded 1/16" diameter, so I took .188 - .062 and got 1/8". Then I thought that if it ended up a bit over 3/16" that would probably help, just not too much over 3/16" and settled on .200 final diameter. That got me to .138.

Thanks for the info. I need to think about it. The option of just making the retainers a little larger is easy and gets me out of the hole. I have plenty of 1/2" CRS to turn down for a couple of retainers, but not much 3/16 rod to make a .155 mandrel from.
 

awake

Well-Known Member
HMEM Supporter
Joined
Sep 4, 2019
Messages
883
Reaction score
315
Location
North Carolina
I turned my mandrel down from something a good bit larger - at least 3/8", maybe 1/2" diameter. My well-worn workhorse lathe has a 10" 3-jaw chuck and an 8" 4-jaw chuck - a wee bit on the large side for model engine work, and the 3-jaw in particular is not good at holding anything much under 1/4" diameter. I do have a small 7x14 lathe, and its chuck works beautifully for holding small pieces ... but no power feed, oddly calibrated (?!) dials, small DOC, PITA tail stock ... I tend to turn even the small parts on the big lathe, if I can figure out how to hold them. (One of these days, a collet chuck ... one of these days!)

Fortunately, I have a lot of mystery steel - which is perfectly suitable for an application such as this - in a variety of sizes from around 5/16" to 1" range, scavenged from various sources. Thus I don't mind turning down a 3/8" rod to a .155" mandrel, and on the big lathe it takes less time to do that than it would to turn a 3/16" rod to .155" on the 7x14!
 

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
I realized I had a long length of 1/4" rod that I got at Home Depot. Mystery Steel for sure. I made a third fixture: .155 diameter and with two ways of fastening the wire. First one is the hole through the mandrel and the second is the tapped 2-56 screw I used on the other one.

Spring-6-Method-3.jpg


I have two ways of threading: one has a minimum speed of 100 RPM and the other has a minimum of 200 (it's CNC and that's a Mach 3 limitation - IIRC).

I know you just used it off the mandrel, but I'm still a bit unsure, since the guy whose instructions I used says to heat treat it. Either way I cut off the ends first.
 

Brian Rupnow

Design Engineer
Project of the Month Winner
Joined
May 23, 2008
Messages
12,401
Reaction score
4,978
Location
Barrie, Ontario, Canada
You don't have to heat treat it---but--it will gradually lose it's strength after prolonged use if you don't. The heat treating "seals in" the tensile strength of the music wire.
 

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
Saturday night is church, so I was back out of the shop while the spring cooled. When I took the spring off the mandrel, it worked better than any of the others. Here's the assembled intake valve assembly with the winding fixture next to it.

BestSpring_09-12.jpg


The retainer fits inside the spring easily, but the spring is a bit tight on the valve cage. I screwed it onto the cage. The other issue is the retainer at the top isn't close to the .040 of the hole, its' a piece of wire from the shop that's under .030. A wire chart says that .040 is #18 wire, and I probably have a little around here somewhere.
 

CFLBob

Well-Known Member
HMEM Supporter
Joined
Feb 10, 2018
Messages
517
Reaction score
84
Location
Central Florida
Finally, both valve and spring assemblies (same "these aren't the final wires" comment as the previous). The second spring in the drawings nearly matched one I had in the shop from somewhere or other (probably a gun project), so I just cut it to length.

Valve_Assys.jpg


Along the way, I got the muffler to mostly-done, except for one cut (to trim off the end at the 30 degree angle). I'm debating whether to do that with a slitting saw on my small mill or just with a hand jeweler's saw.

Muffler-80%.jpg


I honestly don't remember if I finished any other parts while getting these done. I've been putting the parts in a plastic tub on the bench and I think assembling this is going to reveal some things I haven't done.
 

werowance

Well-Known Member
HMEM Supporter
Joined
Sep 2, 2011
Messages
1,000
Reaction score
238
i used my table belt sander to cut (sand) the angle on my exhaust pipe
 

awake

Well-Known Member
HMEM Supporter
Joined
Sep 4, 2019
Messages
883
Reaction score
315
Location
North Carolina
Hmm ... I looked back on my build log for my modified Webster, and realized I never finished it - just had a few miscellaneous odds and ends to add, one of which was the exhaust.

Then I looked at the pictures I took ... and apparently I took none when I was making the exhaust. :(

As best I remember, I turned the part as per the plan (attached), set the part in my vise, protected by some wood (? I think?) at the proper angle, and milled it to the correct angle. I think. Apparently, if I didn't take pictures, I can't remember exactly how I did it!!
 

Attachments

Top