[Anokiernan]

With a more powerful motor in place and counterweighted, and new 387oz-in steppers outfitted to my taig mill, my next obstacle is tackling the machine rigidity.

I've seen posts about filling benchtop machines with composite epoxy concretes, but have never seen anyone attempt to fill a machine with lead. I have access to an abundance of lead ingots (~4 tons) and a few small melting pots. This all just occured to me while at work, but does anyone recognize any potential issues with filling the taig mill's y and z columns with lead?.

The only issues i've thought about have been shrinkage as the lead cools, and the OEM z column support may become inadequate to hold the column in place. Any other ideas?

[Geof]

The shrinkage will likely be a problem in that the lead will be loose so it will not do a lot to dampen chatter.

However, I think a potential problem is the heat. If the castings were not stress relieved before the machine was made you may finish up stressing releiving when the molten lead is poured and and that could be bad news.

I know the melting point of lead is actually below the temperature for stress relieving but you would have to overheat the lead to make sure it filled all the crevices; in fact you almost have to get the castings up to the lead melting temperature which means part of the cast where the hot lead first contacts are probably going to be well above.

[MattTheNoob]

There is a product used my gunsmiths and such, "castaloy?", maybe, that is poured into the chamber of a rifle to produce an exact mold. I'm not sure of the density, but it has a melting point low enough so as not to affect the chamber material, and little or no shrinkage (I think). Probably too expensive for the amount you'd need to fill up a mini-mill, but maybe worth looking into.

How about lead powder or small shot, packed in tight. For dampening vibrations, you may actually be better off with a non-solid.

[Geof]

The product used for gun molds is probably one of the typemetals that used to be used for casting typeface for printing before photo-offset was developed. There are innumerable formulations and some actually expand when they solidify so they make a very good impression of the mold. However, they are expensive and have all manner of nasty things in them like bismuth and cadmium; not really advisable for fooling with at home.

[mactec54]

Just put lead shot in it that way it does not shrink & you don't need any heat, sand is good to & works well

[MattTheNoob]

Kinda like a "dead blow mill".

[rowbare]

I have a Taig as well. I am thinking of doing an E/G fill for the column. Since you have the lead, perhaps you could cut a chunk that will fit inside the column and then use epoxy to hold it in place.

I don't know how to do the base though. It is capped at both ends.

bob

[Anokiernan]

I have a Taig as well. I am thinking of doing an E/G fill for the column. Since you have the lead, perhaps you could cut a chunk that will fit inside the column and then use epoxy to hold it in place.

I don't know how to do the base though. It is capped at both ends.

bob

I'm probably going to try a variation of this. The Y-axis column actually has a gap at the front in which I could pour whatever media I choose into. The tricky part is the Z Column, which is completely open on the bottom. If I'm successful in dampening the taig more I'll be sure to post up the results...

[CalG]

If you have the lead.

just pour in small batches Layers if you will. shrinkage will be filled in by the subsequent pour. heat will be lessened as well.

Go for it!

[bostosh]

Great idea to use lead
Just pour the Pb in in small quantities,
what is your melting capacity? 5-10lbs?
new (hot) will melt/bond to old (cold)
Smaller volumes will not shrink that much

Make a "Kirksite" type mix
I've used this in 1oz to 4000lb molds
very stable stuff

[Anokiernan]

Great idea to use lead
Just pour the Pb in in small quantities,
what is your melting capacity? 5-10lbs?
new (hot) will melt/bond to old (cold)
Smaller volumes will not shrink that much

Make a "Kirksite" type mix
I've used this in 1oz to 4000lb molds
very stable stuff

Yea 5-10lbs is about right, it's been a while since I've dug it up. We used to use it in conjunction with a spin caster. Both systems have been just sitting around collecting dust as of late, it's a shame. With some rough calculations, the lead should add about another ~60lbs to the mill, nearly doubling it's mass. I'm looking forward to trying this

[rowbare]

I am not sure how you have your Taig mounted but here is another idea for some of that lead you have available:

http://www.nyccnc.com/Herbie/HERBIES...eight_Box.html

[BobWarfield]

While the lead sounds like a great idea, epoxy granite will do a better job actually dampening vibrations and has none of the other problems mentioned here for lead. Lots of "pro" machines using E/G, never heard of one using lead for that reason.

Having poured lead for telescope counterweights, I find E/G easier to work with as well.

Here is the E/G fill I did on my IH Mill:

http://www.cnccookbook.com/CCMillEpoxyFill.htm

Subjectively, I'd say it added 15-20% to the overall rigidity of the machine. I have 2 of these IH mills, one with and one without the E/G, so I feel like I have a good handle on it. I don't know if 15-20% is worth it to you, but I'm very pleased with my results.

Best,

BW

[Mark Scrivener]

So did anyone ever try this on a Taig? Just curious if filling the tubular members had a similar benefit on the Taig.

[Anokiernan]

So did anyone ever try this on a Taig? Just curious if filling the tubular members had a similar benefit on the Taig.

I still plan on filling the components on my mill, I simply haven't gotten a chance to play around with it. Due to the rear column being open on both ends, I'll probably be taking the EG route.

[Mark Scrivener]

Epoxy Granite certainly sounds like the most promising route. Just remember to place a tube around the big bolt on the Z column so you will still be able to square up the mill. Anxious to hear how it turns out.

Cheers,
Mark

[ee_t]

Wonder if its worth extending the EG material downwards to allow the z-column to rest on a surface.

Difficulties with this would be:
- building the extension form
- need a large flat surface to mount the mill
- tramming it (maybe allow some space for shims)

Or if its easier to just cap and fill the column, then support it using some of the framing ideas mentioned here before.

[CROSSHATCH]

I poured my mill with concrete.

[rowbare]

I poured my mill with concrete.

Jason,

Tell us more. Did you do both axes? Did you notice an improvement in surface finish after adding the concrete? Any other noticeable improvements?

bob