Epoxy strength vs forces generated in milling

[Alden Banniettis]

I would like to hear some opinions regarding the use of epoxy in the construction of a lathe or mill. I would like to construct a very small, tabletop lathe and milling machine for a youngster. Something akin to a 'working model' machine. The material to be milled would be delrin, or maybe brass. I am retired and have only a small basic workshop nowadays. I am wondering whether I could do the construction using epoxy to bond the steel and or cast iron parts I have laying in my scrap bin. I know I can use epoxy granite for a machine base, etc. But I am now wondering about using epoxy to laminate and build up a headstock, tailstock, etc. Will the epoxy handle the forces generated by this type of milling?

 

[markba633csi]

Sounds doable, you'll just have to use your best judgement as far as strength. Use bolts in addition wherever possible
-Mark

 

[mickri]

Welcome to the forum. Lot of friendly and very knowledgeable people on here that will share their knowledge to help you out with your project.

Pure epoxy is fairly brittle. When strength is needed you have to use various fillers and fiberglass or carbon fiber cloth for strength. You will need to make molds. You have to be careful when grinding and sanding carbon fiber cloth and graphite fillers because the dust will conduct electricity. Some people are highly allergic to epoxy dust from sanding. Carbon fiber cloth is very strong. Strong as steel. It doesn't take much for the strength needed. But you have to add fiberglass cloth to the laminate for bulk.

Depending on how precise you can make the molds very little machining if any would be necessary. I think the biggest problem will be making the beds.

Have you looked into making a gingerly lathe? Search for gingerly lathe and you will get lots of hits on people building these lathes and mills at home.

A cheap drill press with an ER collet adapter in place of the chuck might work for a mill.

This could be a fun project. Keep us posted.

 

[Alden Banniettis]

Thank you, Mickri. I am familiar with the Gingery lathe. This project would be quite a bit smaller, something like a clock-maker's lathe. The kid is thirteen years of age and seems interested in watches and clocks and models, and I figure this project might prove to be somewhat influential in his life, if you know what I mean.

 

[vtcnc]

You might find it more expedient to find a used watchmakers lathe to jump start the process. There is of course large benefit in building your own tools, but if you sense that time is of the essence you may capture his attention quickly and permanently with a used lathe that won’t cost you much more than the cost of epoxy and carbon fiber + layup/mold supplies


Sent from my iPhone using Tapatalk

 

[markba633csi]

I agree- buying him one of the small import lathes (check Craigslist) might be a better option
-Mark

 

[mickri]

You could always scale the gingerly down to the size needed. That way you wouldn't be starting from scratch and there should be answers to any questions that you might have.

I do know what you mean about supporting kids in what they are interested in. I was a single dad that raised my kids from middle school on. One of the biggest things that I stressed was to always strive for excellence. Not perfection but to always do the absolute best that they could do. My son's passion was surfing. He won three national amateur titles including the prestigest Open Mens title while in high school. I spent many a weekend on the beach supporting him. He traveled the world on the pro surf tour for over a decade before going to work for Reef sandals. My daughter was more low key. She developed excellent people management skills and went into teaching after college. Her first classroom was 4th graders. Her principal was amazed at the work she got her 4th graders to do. Her passion is teaching middle school. Currently a stay at home mom raising her kids. The schools where she lives always call her when a position opens up to see if she is ready to come back to teaching.

Put the word out on the forum for stuff you need. Who knows what might turn up. I agree with Bryan that it might be better in the long run to buy a small lathe than to take months building one. You need to capture and nurture that youngster's interest before he moves on to other endeavors.

Did a quick CL search and found these. Lathe- Benchtop 109 - tools - by owner - sale (craigslist.org) Dunlap Craftsman lathe model 109 0702 - tools - by owner - sale (craigslist.org) Don't know how far they are from you or your budget.

 

[macardoso]

Sherline lathes are a perfect tool to learn on. Other companies used Sherlines as a base machine for CNC (Look up Spectralight). This is actually how I got started in machining in my first high school shop class. They are surprisingly high quality and accurate.

Epoxy granite is actually used to build some of the highest quality machine tools out there, and others have used it with success in the hobby space. Your goal is to determine a proper aggregate (gravel, pea gravel, sand, epoxy) which has properties ideal for your needs. As you scale down in size, you can't use large aggregate so it can get tricky. At the end of the day, the working surfaces (spindle, tailstock, ways, etc.) all need to be precision machined components cast into the epoxy granite. You can't slide the epoxy granite over itself. Fiberglass and carbon fiber layups lack the damping characteristics of aggregate based epoxy granite and will likely prove too flexible for machine components. Building one will be a lot of work and you'll have your hands tied behind your back if you don't have access to a mill and lathe to make the metal components to be cast into the epoxy. Feel free to prove me wrong!

If it were me, I'd buy a starter lathe and just start using it. It will also likely be cheaper than building your own.

8" Tabletop Lathe - Package B - Sherline Products

www.sherline.com

7" x 14" Variable-Speed Benchtop Metal Lathe - Grizzly Industrial

<h1>G0765 7" x 14" Variable-Speed Benchtop Lathe</h1><h2>A small bench lathe with impressive torque for small parts production.</h2><p>First and foremost, it features a special "Big Boy" tailstock which was designed with the same convenient quick-locking controls and extra-long footprint...

www.grizzly.com

 

[hman]

I've had pretty good luck joining metal parts with JB Weld. But I always sandblast the mating surfaces before applying the epoxy. This thoroughly cleans off any oils, and gives the surfaces a nice "tooth" to improve adhesion. Wash with plain water to get rid of grit, then with isopropyl alcohol to help dry more quickly.

 

[matthewsx]

Hi and welcome

Yes, epoxy granite machine bases are a real thing and are widely used in commercial CNC machine building.

Mineral Cast Polymer Concrete

BaseTek specializes in the design and manufacture of quality precision mineral polymer castings constructed of Zanite® Plus polymer concrete.

basetek.com

These guys make some pretty cool tool grinding machines right in our little northern Michigan town.

PTG 6L Tool & Cutter Grinder - Star-SU

Engineered to manufacture complex cutting tools, the new Star PTG-6L is a five axis, CNC controlled cutter grinder for manufacturing, sharpening and reconditioning a wide variety of cutting tools. Made in the U.S.A. and equipped with a six-station wheel pack changer, the PTG-6L is built for...

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Also some DIY info on this very site.

Small Epoxy Granite Filled "Watchmakers Lathe" Design Question

I'm a second year mechanical engineering student, and as a summer project I've designed and plan to build a small lathe from bar stock. I am doing this a learning experience and plan to validate all the design aspects with hand calculations and FEA/Modal analysis. The entire machine will only be...

www.hobby-machinist.com

Large Epoxy Granite Vmc Project

Exceeding the performance envelope in every way of my Rf45 clone is the base line goal while being on a budget. I have been accumulating components over the past year. I have come to hate dovetails and am going with linear guides: THK SHS30 for X axis 18”/700mm travel THK SHS 20 for Y&Z axis...

www.hobby-machinist.com

So it definitely can be done. Problem is should it be done?

I planned on using an epoxy granite base for my homemade CNC mill drill project but have pretty much given up on the idea. It's not cheap and you really need to know what you're doing to avoid wasting a bucketload of materials. Finding a used machine and fixing it up is far more practical if not quite as big a challenge.

Regardless, you have come to the right place for exploring whatever ideas catch your fancy....


John