# 1" x 8 tpi spindle tap question



## Truefire (Mar 20, 2007)

I am looking to purchase a 1"x8 tpi spindle tap that is designed to be used for wood and is made or marketed by Beall. I was wondering if the tap was by chance designed to work with a 1" forstner bit for if this tap is designed like all other taps of course an undersized drill size would be used.

Therein lies the dilemma, this tap is designed for woodworkers. i am not presently familiar with any drill bit on the market outside of high speed drill bits that come in such variations of sizes which one may need to use with this tap.

Curious to know if anyone is familiar with this system?

Chris


----------



## crank49 (Apr 7, 2010)

1" x 8 tpi is a standard bolt thread for metal. I doubt, if a specialty wood thread existed, that it would use the same identical description as a metal thread. Bellow are standard metal tap and drill sizes.

INCH SIZES -
NATIONAL COARSE

*TAP SIZE---DRILL SIZE *
1/4-20-------#7 
5/16-18-------F 
3/8-16-------5/16 
1/2-13-------27/64 
5/8-11-------17/32 
3/4-10-------21/32 
7/8-9--------49/64

*1-8--------7/8*

1-1/8-7-------63/64 
1-1/4-7-------1-7/64 
1-1/2-6-------1-11/32

You are in luck. As you can see, the drill size for a 1"- 8 thread is 7/8". That is a standard Forstner or Brad point drill size.

I saw on Woodcraft's site they are suggesting tapping a hole in wood to match the standard thread of a lathe spindle, so YES!, this is in fact a standard metal thread size. It is so you can remove the chuck and just screw the wood workpiece onto the lathe in place of the chuck.


----------



## sarahss (Feb 23, 2011)

I recently checked into it for my Jet Mini lathe with a 1×8 TPI headstock. After talking with Jet and McMaster Carr, they recommended this, but I haven't ordered it yet and don't know if the "pitch" of the threads would be correct or not.

http://www.mcmaster.com/#2521a581/=cz5j9e

don't know if you want to spend that much either, but we got the tap & dye set (1×8TPI)-from Grizzly, I think-anyway, the threads the tap cut were not compatible with my lathe headstock.


----------



## dkirtley (Mar 11, 2010)

It is a metal tap to match the metal threads. I have one but have not used it yet. I believe the instructions do say 7/8 bit but I would have to go look when I get home.


----------



## Truefire (Mar 20, 2007)

Thanks guys, i actually called Craft Supplies USA today and spoke with a rep and to reiterate what you guys are saying, the rep said the particular 1×8 spindle tap in question does utilize a 7/8" pilot hole.

So there i go!

Thanks again, Chris


----------



## bubinga (Feb 5, 2011)

The 1×8 tap does use a 7/8" bit, a brad point is much better choice, and you can buy it,( and odd sizes) from Beall Tool
The tap you are looking to purchase, has a removable guide on the end,that guides the tap straight
I have made, and tapped wood nuts for 1/2", 5/8",3/4", 1", 1 1/4" and 1 1/2", wood bolts.
IMPORTANT: When tapping in wood, clamp in vise to avoid splitting


----------



## Truefire (Mar 20, 2007)

"IMPORTANT: When tapping in wood, clamp in vise to avoid splitting

-E J"

THanks EJ, with this tidbit i will not have to go through the school of hard knocks in this area. Chris


----------



## Zepluros (Jan 20, 2013)

Update for this thread, Woodcraft and Amazon both have this tap and it works great on my Rikon mini lathe. 7/8" forstner bit works for the pilot hole. Turn in lathe if possible using tapered center to keep straight, backing the tap up frequently to clear chips.


----------



## darb (Dec 5, 2015)

HI all, I recently bought a box full of wood lahe tool rests and face plates. I have a Delta 46-544 and i believe the spindle sise is the 1", however, the face plates are a smaller thread sise. My question is can I use the smaller face plate spindle sise by buying a reducing spindle from one sise to accommodate the smaller face plater. Ps, i am mispelling because my key board is defective. Thanks Harry


----------



## BasementShop (Nov 3, 2014)

> My question is can I use the smaller face plate spindle sise by buying a reducing spindle from one size to accommodate the smaller face plates.
> - darb


You may be able to adapters to go from one size lathe to a different size face plate. Give the good folks at Craft Supply to find out what they can do for your particular sizes.


----------



## MrUnix (May 18, 2012)

Going from smaller to larger is not usually much of a problem (to a point).. but going from larger to smaller becomes problematic as it extends the spindle length and weakens the spindle strength - which is sort of important when using a faceplate for stuff like bowls that involve a lot of force, and really need to be as close to the headstock bearings as possible.

If the face plates have thick enough walls around the threads, you may be able to re-tap them to the correct size/TPI, but that depends on just how much smaller they are. At any rate, a good metal tap the proper size would be required, and if you do get one, you can use it to make wooden faceplates as well (metal taps work just fine for wood).

Do you know the size/tpi of the smaller faceplates? It may be more economical to just sell them and get the correct size for your lathe if you need them. I have a metal faceplate for my lathe and never use it - pretty much just use wood ones I make myself. I do keep the metal one though, just 'cause 

Cheers,
Brad


----------

