3/4" Raritan 2-4-0 build.

shild · Post by **shild** » Sat Jan 30, 2021 3:46 pm

Bill Shields wrote: ↑Sat Jan 30, 2021 12:47 pm @Marty:

that is the construction manual that Joe T provides. It is Very helpful...and IIRC includes Baker gear design.

@Shild

keep a log of what you do and how long it takes.
Make notes of what you learned / found difficult / tools you needed that you did not have.
An Excel spread sheet is my preferred way of keeping track.

You will be amazed at how much time you put into 'making parts' / making fixtures.

I am just 4 years into my current project with 700 hours on the main chassis (runs on air), 250 hours into the tender (ready to paint) & 130 hours into a hydrotested copper boiler. Don't ask about $$$

I am not as quick as Jack B (or artistic since I tend to 'build to run'), but I do have 99% of the necessary tools available to keep things moving..not my first loco...nor even my 6th....while a slow learner, i am dedicated to seeing a finished product.

nibble away @ it a few hours a week and things get done...just don't bite off more than you can chew.

and yes, I work a 50+ hour week and maintain a 100 acre working farm in my spare time.

I see. Your project is in this build log? At the moment I'm trying to do the tenders truck side frames. Using 1/4" steel and am having trouble milling a slot all the way through without it chattering. Not sure if I'm better off with multiple passes or drilling a row of holes first?

jcbrock · Post by **jcbrock** » Sat Jan 30, 2021 8:00 pm

You may know this already, but another thing about taps, you are going to want both bottoming taps and then either plug or taper taps. If you're tapping a blind hole, you start with the plug or taper tap and then finish the last few turns with the bottoming tap. I frequently back off to free up chips. If tapping through holes you can do them with either the plug or taper taps. MSC sells sets of all three types, but I've never seen a huge need for both plug and taper taps as they both seem to work. Also, use a lubricant like TapMagic, and when the tap starts to tighten up in the hole, do NOT make that last quarter-turn!

Bill Shields · Post by **Bill Shields** » Sat Jan 30, 2021 10:07 pm

My project is not in build log.

Chatter is a function of material, cutter and rigidity. Do not be in a hurry.

Putting a tool into 280 degree of cutting I's a worst case scenario.

Go slow and light..u r not in a speed race...

Greg_Lewis · Post by **Greg_Lewis** » Sat Jan 30, 2021 11:03 pm

I think chatter is also a factor of the alignment of the planets!

Be sure that everything is as tight as you can get it. If the gibs are loose on the mill table, that can contribute. Lock the direction you're not using and tighten the lock on the moving side so it will just barely move when you turn the crank handle. Don't try to cut the slot in one pass. I prefer to cut undersize and then bring to size with a new two-flute mill. If the slot is an exact size that corresponds with a mill diameter, you can do it in one pass. Otherwise you take a cut on each side of the slot, being careful to insure that you are cutting the appropriate amount off each side of the slot.

shild · Post by **shild** » Sun Jan 31, 2021 11:38 am

Bill Shields wrote: ↑Sat Jan 30, 2021 10:07 pm My project is not in build log.

Chatter is a function of material, cutter and rigidity. Do not be in a hurry.

Putting a tool into 280 degree of cutting I's a worst case scenario.

Go slow and light..u r not in a speed race...

Now what do you mean by 280 degree of cutting? I thought endmills did at most 180 while going sideways.

shild · Post by **shild** » Sun Jan 31, 2021 11:41 am

Greg_Lewis wrote: ↑Sat Jan 30, 2021 11:03 pm I think chatter is also a factor of the alignment of the planets!
Be sure that everything is as tight as you can get it. If the gibs are loose on the mill table, that can contribute. Lock the direction you're not using and tighten the lock on the moving side so it will just barely move when you turn the crank handle. Don't try to cut the slot in one pass. I prefer to cut undersize and then bring to size with a new two-flute mill. If the slot is an exact size that corresponds with a mill diameter, you can do it in one pass. Otherwise you take a cut on each side of the slot, being careful to insure that you are cutting the appropriate amount off each side of the slot.

A 2 flute to finish? With a climb cut?

shild · Post by **shild** » Sun Jan 31, 2021 11:46 am

jcbrock wrote: ↑Sat Jan 30, 2021 8:00 pm You may know this already, but another thing about taps, you are going to want both bottoming taps and then either plug or taper taps. If you're tapping a blind hole, you start with the plug or taper tap and then finish the last few turns with the bottoming tap. I frequently back off to free up chips. If tapping through holes you can do them with either the plug or taper taps. MSC sells sets of all three types, but I've never seen a huge need for both plug and taper taps as they both seem to work. Also, use a lubricant like TapMagic, and when the tap starts to tighten up in the hole, do NOT make that last quarter-turn!

I don't believe I've come across a situation yet where I don't have room to drill the hole deeper for sufficient thread and have to use a bottoming tap. What are some examples of this?

Greg_Lewis · Post by **Greg_Lewis** » Sun Jan 31, 2021 11:51 am

shild wrote: ↑Sun Jan 31, 2021 11:41 am A 2 flute to finish? With a climb cut?

If you are making the final cut with an on-size cutter, the cut on one side is balanced off by the cut on the other side. No problem. You do want to do this with a new cutter so it will be on size and sharp.

Bill Shields · Post by **Bill Shields** » Sun Jan 31, 2021 12:17 pm

280 is a fat fingered 180.

There is a science to preventing chatter...but at your level of experience. Just go slow..

shild · Post by **shild** » Sun Jan 31, 2021 2:28 pm

I don't know if one could count this as chatter or not, but when I do a heavy cut, the sheet metal from the cowl on this mill will buzz big time. I just stuffed some cotton balls between the column and the cowl and the buzzing went away. During cuts somewhere in between heavy and light the gears teeth chatter between each other. Thinking about trying some very thick grease on them. Is that the right thing to do?

shild · Post by **shild** » Sun Jan 31, 2021 2:49 pm

Well this is the level I'm at anyway. Trying to do the side frames for the tender trucks 2 at a time, then I'll saw horizontally in the middle to get my 2 truck side frames. This makes it so the slots for bearings are the same on both sides, doesn't it? Then I'm doing the truck bolsters. Bill, I take it you've done this locomotive before if you already knew this book I have has the extra stuff?