MEG steam Wendy Reconstuction

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Harold_V
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Re: MEG steam Wendy Reconstuction

Post by Harold_V »

ChipsAhoy wrote: Mon Apr 25, 2022 3:41 am I am not a machinist, just at a hobby level.
Help me out here.
By "roughing", you mean to make the piece close to dimension in bites, perhaps using a "roughing" end mill before the final cuts?
Then switching tooling for the final passes?
Scotty
One roughs to avoid changing of dimensions and flatness in the work piece. All material, including hot rolled products, have internal stresses. They are relieved (at least partially) when material is removed, and that causes the material to move. The more uniformly material is removed, the less movement, but that isn't generally possible (lathe work tends to be the exception).
By roughing, where one leaves material for final removal, the movement caused by stress relief relaxes the remaining material, so when final passes are taken little to no further movement results, so you can better achieve the desired result.

One need not make tool changes, but it's a smart thing to do. Roughing often dulls the tool in use. By switching to a sharp one, the cut generates less heat and demands less cutting pressure. While roughing type cutters are to advantage, they are not mandatory. As a bonus, once roughed, finish cuts can usually be climb milled instead of conventional milled (due to the small amount of material being removed), so surface finishes are automatically improved. Best of all, the part is far more stable and will generally result in a more precise piece, free of error from movement.

Roughing before finishing is considered good shop practice, for obvious reasons. Surface finish isn't generally considered, as the prime objective is to shape the part. Roughing cuts are generally quite heavy, with high rates of feed, removing material as quickly as possible. However, do not sacrifice relationships of the features. Look at a roughed part as starting with a casting. Inside that roughed part resides the finished part. You must maintain concentricity, perpendicularity and reasonable size. As a guide, consider leaving anywhere from .03" to .05" on finished dimensions. Half that amount would be removed per side upon taking finished cuts. The larger the work piece, the more material one would leave. The smaller amount that allows for full finish cuts dictates that the piece in final machining will move less, if at all.

Some material is very active. I had one job that required a rough, semi-finish and finish operation to avoid movement. That is exceedingly rare--the material being Delrin.

H
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skyloop440
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Re: MEG steam Wendy Reconstuction

Post by skyloop440 »

Hello all you WENDY fans, I would like to thank everyone who has chimed in here with some very good advice, info, photo's etc., that I plan on using. Photos of the next round of parts are attached. I changed the journal box slide bars from 1/2" x 1" flat bar to a U-shaped part, the British call them (Main horn blocks). I believe there stronger and will give a little more support around that area of the frame. The next is the Floorboard and rear frame spreader, I lengthened and widened the floorboard because I want the larger cab. Then there is the flue sheet that welds to the front of the fire box. I guess that's it for now time to start drilling and tapping holes. Keep up the good info.

Matt
Attachments
Main horn blocks
Main horn blocks
Floorboard and rear spreader plate
Floorboard and rear spreader plate
Flue sheet
Flue sheet
Last edited by rmac on Tue Apr 26, 2022 9:07 pm, edited 1 time in total.
Reason: Photo Orientation
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10KPete
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Re: MEG steam Wendy Reconstuction

Post by 10KPete »

You are living my dream....
Keep it coming!
Pete
Just tryin'
skyloop440
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Location: colorado

Re: MEG steam Wendy Reconstuction

Post by skyloop440 »

Hi Pete:
Will Do.
Matt
skyloop440
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Re: MEG steam Wendy Reconstuction

Post by skyloop440 »

Hello Wendy fans:
Not much to report this week. I tapped the 24 holes in the Main frame horns, Chamfered the 37 flue holes in the back flue sheet for welding, sand blasted the flues and made sure they all fit in the holes. Had the piston rods made out of drill rod, i was not set up to thread it in the lathe so i had them made, drill rod does not tap good by hand. I made a change to the piston end of the rod. The prints call out 3/8" rod turned down to 5/16" on the piston end, i had them made 3/8-24 on both ends didn't see the reason to reduces the size. That's about it for now should have the next round of parts in a day or two and the welding on the frame should be done soon as well.
Matt
Attachments
Rear flue sheet with chamfered holes
Rear flue sheet with chamfered holes
Sand blaster flues and fire box (tube)
Sand blaster flues and fire box (tube)
Main frame horns and piston rods
Main frame horns and piston rods
Last edited by rmac on Mon May 02, 2022 8:34 am, edited 1 time in total.
Reason: Photo Orientation
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Harold_V
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Re: MEG steam Wendy Reconstuction

Post by Harold_V »

skyloop440 wrote: Sun May 01, 2022 10:09 pm i had them made 3/8-24 on both ends didn't see the reason to reduces the size.
I am not familiar with the parts in question, but if the piston was intended to have a 5/16" bore for the rod to fit, you may have eliminated the shoulder that would locate the piston on the rod. That shoulder is what would keep the piston on the rod in proper location. Without it, it is free to move along the rod. Is that the case?

H
Wise people talk because they have something to say. Fools talk because they have to say something.
skyloop440
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Re: MEG steam Wendy Reconstuction

Post by skyloop440 »

There would have been a shoulder but there is no need for one there, the rod threads into the piston until it bottoms out on the thread, then there is a jam nut put on from the other side which is recessed into the piston face. With some lock tight it will be as solid as silver soldering it in place.
Matt
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Harold_V
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Re: MEG steam Wendy Reconstuction

Post by Harold_V »

skyloop440 wrote: Mon May 02, 2022 9:10 am There would have been a shoulder but there is no need for one there, the rod threads into the piston until it bottoms out on the thread, then there is a jam nut put on from the other side which is recessed into the piston face. With some lock tight it will be as solid as silver soldering it in place.
Matt
Thanks. That makes sense, although I don't think I'd have eliminated the turn. Here's why. If, in tapping the piston, there's any error, it may not thread on the rod perpendicular, and it could also have some runout (it most likely will suffer from both conditions to some degree). By boring the hole in the piston and stopping against the shoulder, that condition is generally eliminated. I wouldn't have made the same choice for that reason.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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NP317
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Re: MEG steam Wendy Reconstuction

Post by NP317 »

What Harold advised.
Definitely.

Through mechanical working, the piston likely will loosen on the threads a little.
Especially considering the temperature cycling that will accompany using steam.
RussN
skyloop440
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Re: MEG steam Wendy Reconstuction

Post by skyloop440 »

All consider what you have said about the rod, it can still be redone. Here are the parts i picked up today. The Front flue sheet, the throttle sheet and the smoke box door blank. the flue sheets are of the Uncle sam design were the steam dome is inside the cab and the throttle pipe comes out of it threw a ball valve and threw the boiler Wendy used a smoke box throttle.
Matt
Attachments
Inner boiler parts
Inner boiler parts
Cab throttle (Harlock photo)
Cab throttle (Harlock photo)
smoke box ring
smoke box ring
Front flue sheet
Front flue sheet
Throttle sheet
Throttle sheet
Last edited by rmac on Mon May 02, 2022 9:39 pm, edited 1 time in total.
Reason: Photo Orientation
skyloop440
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Re: MEG steam Wendy Reconstuction

Post by skyloop440 »

Here are a couple drawings of the flue sheets
Attachments
FRONT FLUE SHEET.PDF
Front flue sheet
(66.67 KiB) Downloaded 147 times
THROTTLE SHEET.PDF
Throttle sheet
(28.27 KiB) Downloaded 135 times
skyloop440
Posts: 126
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Location: colorado

Re: MEG steam Wendy Reconstuction

Post by skyloop440 »

My Pictures got messed up or deleted somehow, I was informed that I have been loading them wrong and they have to be corrected. I will try and load them differently to fix this, Sorry for the mishap.
Matt
Attachments
SMOKE BOX RING.PDF
Smoke box ring
(56.47 KiB) Downloaded 142 times
Smoke box ring blank
Smoke box ring blank
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