Radius Gauges? School Me...

[Cruzan80]

So tried to find some information about these, but either the search terms I put in were off, or nobody had an opinion before this (highly doubt it is the latter).

Looking to find a set for decent money, without breaking the bank. Not a machinist, most of this will be for reproduction work on a lathe, 3d printing and CAD design, etc. I hav eseen some at various price points, and I know sometimes the cheaper stuff is good for 95%, and the last 1-5% is $$$$$!

Looking around, I think I would rather get the ones that have outside/inside curves and a mounting handle, rather than the ones that look like feeler gauges. Not sure how big I should go, is it possible to get larger sizes individually later, or can't find/cost prohibitive? Have a feeling I will need to get SAE/Metric, and match the closest sizing, or do things generally follow patterns (most common USA-made things, especially vintage, don't have metric, all cars use metric curves, etc)?

Seeing sets all over the place for the money. Since I don't have $200+ to drop on a single set, what is the best balance of cost/quality? I have been keeping an eye out for local stuff, but either it is all over my budget (not going to say overpriced, because I don't know the market well enough to make that judgement call), or goes really fast. Really hoping to find the guy retiring that is selling everything for under $300, but that unicorn isn't here yet.

 

[ER70S-2]

Do you mean something like these?

https://www.amazon.com/64-1-Radius-gage-Set/dp/B005GLJMOI

 

[Cruzan80]

Yes, something like that. I have seen a few sets on Amazon under $30 (their best-seller is around 25/each for Metric/SAE). Just wondering if I should avoid certain brands, or others are worth the bit of price increase.

 

[dr_clyde]

I have Starrett and General sets up to 1/2". Larger than that they get expensive fast. I have been thinking of getting some cut from 14ga SS on the laser up to like, 3 inch for reverse engineering stuff for CAD models.

General brand is more than adequate for non fussy work.

 

[bugnut]

Sets up to 1/2" are easy to come by used. Craigslist ads for machinist tools, is were to find them. If you need specific outside sizes large than that I have used or made them from a set of hf hole saws, for inside I just use the hf hole saws thru a pc of masonite. Depends on accuracy required.

 

[davethorik]

Never did care for the thread pitch gage/fold out style, personally. I like the loose sets in fold-up vinyl case with holder stylus, as you mentioned.

I have a 26 pc set of Pratt & Whitney decimal radius gages in hardened stainless steel, from .010" to .500". This is my go-to set as I prefer decimal to fraction. Identical to Lufkin.

I also have an 8 pc set of large Lufkin fractional radius gages, from 9/16" to 1", increments of 1/16". This set complete is pretty heavy, and gages surprisingly large and thick compared to smaller sizes. They are older heat treated tool steel and will rust, I'd prefer stainless but these were so cheap I'm okay with it. I just keep them oiled.

Then as a backup/loaner I have a 25 pc set of no-name fractional gages, 1/64" thru 1/2". These are stainless, but I believe a non-hardened alloy, guessing 300 series.

I think I have around $40 into all 3 sets, and the no-name set was free.

 

[Cruzan80]

Thanks guys. So it sounds like the consensus is that I would be fine with the "under $50 new" stuff (up to 1/2"). Thought that was the case, but nice to have it confirmed. All the CL stuff I have seen has been parts of sets wanting 425-600+ for radius/pin/blocks/etc.

Any idea how ebay would be for the used stuff? Wondering if I stick with older brands (General USA, P&W, others, etc) would it fly under people's radar more than Starrett, B&S or Mitutoyo?

 

[Mohawk Dave]

I seem to see the Lufkin set in the red leatherette case at every garage sale.

I think they'll sets go up to half inch. Maybe I have an extra one laying around. I will look and let you know

 

[davethorik]

I seem to see the Lufkin set in the red leatherette case at every garage sale.

I think they'll sets go up to half inch. Maybe I have an extra one laying around. I will look and let you know

I believe that Lufkin invented the radius gage.

https://patents.google.com/patent/US1825987

Those red leatherette sets are everywhere. I prefer the later hardened stainless gages in the vinyl fold up pouch, because the originals always wind up oxidized and looking like ****, and it's a pet peeve of mine.

 

[Dave455]

I believe that Lufkin invented the radius gage.

https://patents.google.com/patent/US1825987

Those red leatherette sets are everywhere. I prefer the later hardened stainless gages in the vinyl fold up pouch, because the originals always wind up oxidized and looking like ****, and it's a pet peeve of mine.

It would seem Lufkin invented one particular pattern of radius gauge.

In the application they make reference to the fact that the tool is “of the type known as a radius gauge” so the tools obviously existed well before that.

I’ve seen very old radius gauges in the U.K. probably dating back to Victorian times, I’d be surprised if they didn’t exist in the U.S. in the same era!

There are many different patterns. If you just want simple internal/external radii, and don’t want the fold up style, you can get sets of simple gauges on rings.

 

[Dave455]

Here’s a set on U.K. eBay. £6.50 and no bids with 15 mins to run!

Probably not going to be big money.

O.P. - eBay is great for that sort of stuff!

I’d be wary of buying stuff like dial gauges that are prone to damage that you can’t see, but with something like a radius gauge there’s not much to go wrong.

I’ve bought few engineers tools new and have no regrets. The older stuff is often better quality anyway!

Here in the U.K. we have quite a few second hand tool shops which are great as you can check stuff before you buy, but if you are careful I’d buy from eBay too!

 

[leg17]

One thing to watch for with used radius gages is wear from being used as cutting tools for wood or graphite.
I have used them to round off EDM electrodes and have heard of similar practice on wood turning.
(I didn't use my good ones but an older rough set)

 

[MShaw]

"I have a 26 pc set of Pratt & Whitney decimal radius gages in hardened stainless steel, from .010" to .500". This is my go-to set as I prefer decimal to fraction. Identical to Lufkin."

They are identical to lufkin because Pratt & Whitney bought out Lufkin in about 1970 and made the line until the demise of Pratt & Whitney.

 

[davethorik]

It would seem Lufkin invented one particular pattern of radius gauge.

In the application they make reference to the fact that the tool is “of the type known as a radius gauge” so the tools obviously existed well before that.

Thank you Dave for the correction, yes Lufkin invented the type of radius gage most common in the states, from what I can tell. Not like a curved piece of metal or wood is really a mind blowing invention anyway lol

They are identical to lufkin because Pratt & Whitney bought out Lufkin in about 1970 and made the line until the demise of Pratt & Whitney.

Actually November 1966 is when P&W bought their machinist tool line...then the name, and rest of Lufkin's carcass (mostly tape measures) went to Cooper Industries in 1967.
I'm an avid Lufkin and P&W machinist tool collector, I just usually don't include details that 99.9% of members here don't care about and will just skim over, because it is a fairly obscure thing to collect/have an interest in.