# Drilling Lathe Bed- Foot Bolt Pattern Mismatch



## wildo (Feb 21, 2016)

I ended up purchasing the adjustable lathe feet that I was asking about in this thread. This weekend I went to mount them and the sad reality hit that the bolt pattern was different! The actual machined surface that is the contact point for the lathe bed to rest on is the proper width though. 




You can see the feet fit under the lathe nicely.



My question- is there any particular reason that I shouldn't be able to drill & tap new holes in the lathe bed? Since it's two machined surfaces sitting against each other, the hole alignment should be practically irrelevant as long as the foot is sitting properly under the bed. So if the feet are drilled for a loose clearance and the bed drilled/threaded, wouldn't that work?

I thought it would be possible to just drill out the feet to fit the pattern of the tapped holes in the bottom of the lathe bed, but unfortunately this won't be possible. On the tailstock side, the leveling mechanism would be in the way, and on the headstock side, the foot doesn't have material under the front most bolt locations.

On both the headstock and tailstock sides, I could get the outermost two bolts in just fine. It's the inner bolts that are the problem.

I'd love to hear some thoughts on this. Is drilling/tapping the bed a big deal? Is that a major no-no or something? Beyond the difficulty of drilling the cast iron, I can't really see any reason why it shouldn't work just fine. Am I missing anything?


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## 4GSR (Feb 22, 2016)

Go for it!

Be aware, cast iron is very abrasive. You may wear out a drill bit or two, or at least re sharpen them as you go.  Use four flute plug taps, not gun taps for tapping the holes.  Tap dry.


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## wildo (Feb 22, 2016)

When I was restoring my Buffalo drill press, I needed to drill two holes in the cast iron head for some screw nails. I picked up a carbide tipped drill bit from McMaster-Carr and it seemed to go through the cast really nicely. So I was considering getting a larger bit for the lathe bed. That might mitigate the wearing down on the bit. I did some research today and found lots of info about tapping cast- especially to tap dry. I assume that also means you drill dry, yes?


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## wildo (Feb 25, 2016)

Thanks for the response Ken. This ended up being way less of a deal than I expected. While I did purchase a carbide-tipped drill bit, the tip cracked off when the drill bit punched through the second hole. I reground the drill bit (which would be the HSS remanent) and didn't really have any issue getting the last two holes drilled. The tapping was quite easy.

Tailstock end- two new holes closest to the headstock:



Headstock end- two new holes closest to the tailstock:



Drilling/tapping on the tailstock side:









What a great modification!


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