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Project Logs / Re: Sheet Metal Brake and 3d Printer.
« Last post by PekkaNF on Today at 10:05:43 AM »
I was affraid that the form tool would dig itself into work, therefore "front relief" was pretty small, you almost need to push it into POM (Think I needed to adjust it just tad "under" centre line) and it does not crab. It is pretty sharp on the front (big "Back rake") to sheave off nice swarf. Thermo plastics are next to dog sh*t compared to tool steels when it comes to cutting forces. This would not work with most of the metals on these dimenssions (metals you get chatter or resort to skiving tool).


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Project Logs / Re: Sheet Metal Brake and 3d Printer.
« Last post by S. Heslop on Today at 08:23:19 AM »
It's reassuring to see that huge form tool cut without any chatter. I've heard acetal machines well but never had a reason to try it.

That's a beautiful mandrel too.
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Project Logs / Re: Sheet Metal Brake and 3d Printer.
« Last post by PekkaNF on Today at 05:26:38 AM »
....
I am planning to machine all the parts I can handle on the lathe though, as well as czech out how deep a chamfer I can cut with delrin. ..
...

I did some batches of rope pulleys out of POM (Delrin). Check this thread, hope is inspirational.
https://madmodder.net/index.php/topic,12053.msg143327.html#msg143327

Pekka
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Metal Stuff / Re: homemade anvil
« Last post by Brass_Machine on Today at 12:29:54 AM »
Wow!

 :jaw:

Eric
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Project Logs / Re: Sheet Metal Brake and 3d Printer.
« Last post by S. Heslop on September 23, 2018, 08:03:51 PM »
I'm in the UK i'm afraid, but thanks for the offer.

I am planning to machine all the parts I can handle on the lathe though, as well as czech out how deep a chamfer I can cut with delrin. For Z belt idlers i've got a whole bag of 8mm hole toothed pulleys.

I did find the build instructions. They were a big help for figuring out what half the plates are for. Although i've spotted a couple errors I made since posting the sketchup model, such as using the same motor bracket as the X axis for the Z steppers, which was reducing the volume a bit.
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Radio Control Models / Re: Glow plug position
« Last post by SeaCat on September 23, 2018, 07:06:01 PM »
If the engine is a 2 stroke, the end of the glow should be level with the end (combustion surface) of the cylinder head. 

If it is a 4 stroke, the the end of the glow plug - the bit from the end of the thread to the glow tip - should stand proud of the head; if this would mean the plug end fouling the piston at TDC then recess the end of the plug in the head.  This is because with a 4 stroke, the plug end needs to heat up and hold the heat twice as long as a 2 stroke plug does! Hope this helps,

Chris
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How do I?? / Re: Making my first boiler
« Last post by chipenter on September 23, 2018, 02:45:47 PM »
Have you thought  of spinning the flanges for the ends ? flanges in as then the boiler has a larger volume , as it tube is smaller diameter have you increased the length to give you the same volume ?
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How do I?? / Making my first boiler
« Last post by Chuck in E. TN on September 23, 2018, 10:47:17 AM »
I’m ready to make the end plate formers for my small horizontal pot boiler. The body tube is 1.625” od,  and 1.512” id, thus a wall thickness of .056”. I have both aluminum, and oak available for the formers. Are there any hard/fast rules or formulas for making the formers? With either material, I plan to have a center hole for a mandrel to turn them on. I’m leaning toward turning the former out of aluminum, as I have enough copper tube for a couple more.
I’m also making the end plates from pieces of the tube, so the end plates will be .056” thick. What would be the minimum radius for the flange? How wide should the flange be?
I’m following Stan Bray’s design Boiler # 1, in chapter 14 of the book “Making Simple Model Steam Engines”, but I couldn’t find 2” or 50mm tube. I assume the former diameter would be tube id – (wall thickness x2) and the blank disk should be a diameter of tube id + (flange width x2), with some allowance for the radius of the flange bend.
Last question, which is the best orientation for the end plate in the body tube, flange pointing in or out? Why?
Thanks,
Chuck
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Project Logs / Re: Sheet Metal Brake and 3d Printer.
« Last post by WeldingRod on September 23, 2018, 10:05:57 AM »
Are you in the US or UK?  There's some screws you only need 2 of, and I bought box quantities...  happy to share!  PM me your ship-to if you'd like some.
I might have a spare double pulley, gotta check...  I highly recommend the double belt with the shaft across the front.
I machined the idlers for the Z belt loop.
I need to see if that made it into the docs. (Long pause)   yes, it's in there.
Did you find the google doc instructions?  If you PM me your email address, I (think) I can give access to the common doc.
Rod

Sent from my SAMSUNG-SM-G891A using Tapatalk

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Project Logs / Re: Sheet Metal Brake and 3d Printer.
« Last post by S. Heslop on September 23, 2018, 12:00:58 AM »
Just placed the order for all the extrusions and corner brackets. I'm maybe jumping the gun a bit, but I figure if I sit on this thing any longer i'll never get it started - let alone finished.

Through the week i'll have a look around to get some quotes on plasma cutting for the plates, and also assemble a list of all the fasteners i'm gonna need.
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