# Taper Attachment For The G0709 Lathe



## BGHansen (Oct 27, 2015)

I took advantage of a recent Grizzly 10% off coupon and bought a model T10502 taper attachment for my model G0709 14” x 40” gunsmithing lathe.  I have a number of items on my wish list for this lathe:  8” 3-jaw chuck, 5-C collet chuck and a taper attachment.  Maybe my wife will read this write-up and take care of the first two items this Christmas!
The following is my experience installing the accessory.  Pros and cons will be covered.  First, the packaging which was excellent.  The attachment came in a tightly packed small crate, shipping weight was 55 lbs.
Grizzly manuals have been considered the industry standard.  No exception here except my attachment varied slightly in some areas from the manual.  Everyone in our “trade” is mechanically inclined, so there’s nothing anyone of us couldn’t figure out.  The thrust bearing arrangement at the new cross feed hand wheel bracket was different than the manual parts diagram.  Not a problem as I noted how things went together before taking them apart during installation.  The manual differences might be because the instructions are shared between the taper attachments for the G4002/3, G0750 and G0709 lathes.  The attachment for the G0709 lathe has a maximum of 12” of travel, the manual states it is 9”.  Most likely those are the specs for the 12” lathe(s) attachments.
By the way, the Grizzly manual for this taper attachment is available on-line. Go to Grizzly.com, search for G0709, click on the taper attachment at the bottom and click the link to the manual.  I used their names for the parts described in this review.
The instructions say to align the taper body flush with the top of the cross slide dovetail, punch/drill/tap holes to attach the body to the carriage.  The casting is shaped as such so normal transfer punches won’t work.  I made up a stubby punch out of a 3/8” bolt turned down to tightly fit the holes in the body bracket.  Only needed for two hits through paint into cast iron so it wasn’t hardened.  The top of the cross dovetail is not a “datum” surface.  As a result, the body was too high by about 0.060” on my installation.  The cross slide lead screw nut moved uphill as it travelled across the carriage.  The cross feed handle was very stiff because of the bind.  I had to slot the body bracket holes at the top by about 0.070” so the cross slide nut moved parallel to the saddle dovetail surface.
If I had it to do all over again, I’d clamp a couple of bars to the two lower dovetail surfaces on the carriage and extend them out and over the taper body.  I’d sub-assemble the new cross feed lead screw to the alignment block and install it to the carriage.  Then clamp the taper body to the two pieces of bar stock and run the cross feed nut back/forth checking it for flushness to the top surface of the carriage dovetail.  If the nut runs uphill as in my initial installation, shim the taper body down appropriately before punching/drilling and tapping the holes to the carriage.
The supplied bolts (25 mm long, parts list shows 30 mm long) for attaching the taper body to the carriage were a little short for my liking, only about ¼” of engagement to the carriage.  As designed, no flat/locker washer are used either.  I substituted bolts about ½” longer and added flat washers and lock washers.  Probably a case of overkill on my part, but I prefer the belt and suspenders.
The bed clamp bracket was about 0.030” thicker than the bed.  As a result the bed clamp block bottomed out on bracket bottom before clamping up to the lathe bed.  I machined 0.050” off the surface of the bed clamp bracket above the bed clamp block so it would clamp properly to the lathe bed.
The new cross slide nut was not tapped for screwing to the cross slide.  I drilled/tapped an M8 x 1.25 thread for the attaching screw.  Maybe this is a generic taper attachment for 14” lathes, maybe there are variations in the location and thread size of the tapped hole.  I merely measured the original nut and matched the hole location.  I didn’t mic the new lead screw vs. the original, but they are subtly different.  I couldn’t thread the original nut on the new lead screw, both are 10 tpi.
Curiously, the new cross feed mounting bracket had no cross hair line for reading micrometer dial settings.  I cut a line with a machinist square and carbide scribe.  The original bracket has the cross hair line and notes that the graduations are 0.002” apart.  The new micrometer dial has the 0.002” note on it instead.  My presumption is the cross hair line needs to be scribed by the user by design, no idea why it wouldn’t be factory scribed.
The kit includes pull dowels to hold the position of the body bracket to the carriage, but nothing is mentioned about them in the instructions.  Moreover, the parts lists shows spring pins.  You would think the dowel holes would be match drilled/reamed into the carriage once the slide table is indicated as flat to the carriage.  However, the dowel holes are inaccessible as designed.  I ended up drilling additional holes outboard of the original ones in the taper body for doweling.  I made extensions for drilling/reaming the holes for 5/16” pull dowels.
The new cross feed lead screw far end is attached to the alignment block with thrust bearings on either side of the block and nuts on the far side.  I had to add a couple of spacer washers so the cross feed lead screw was tight to the alignment block.  Otherwise the cross slide would “chuck” back/forth.  The taper attachment came with a bracket not used on the Grizzly lathe.  My presumption is the alignment block is thinner than the bracket not used thus requiring the added spacer washers.
Personal preference:  I don’t like the clutch drive adjustment system for the micrometer dials.  Give me a good old lock screw with a free-spinning dial!  I drilled/tapped a ¼-20 hole for a new 303 stainless lock screw/brass button.  Again, just my preference as I was concerned about turning the cross feed crank slightly as the micrometer dial was zeroed.
The installation took me about 4 hours.  Happy?  You betcha!  You’ve got to love a telescoping taper attachment over the plain type!  No need to disconnect the cross slide lead screw nut when tapering, plus the cross feed stays fully functional.  Tapering is just a matter of setting the angle between the pivot block and angle scale plate and locking the bed clamp bracket to the lathe bed.  The taper attachment performs well, seems rigid for the cuts made so far.  Not an accessory I will use every day, but I do have a couple of jobs that require it.  Very nice addition to a very nice lathe.


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## 4GSR (Oct 27, 2015)

BGHansen,

Nice writeup you did on installing a new taper attachment the correct way.  This can also be applied to most any taper attachment out there in the machine world.  New or used.  I've rebuilt, installed a few over the years and yet found detailed instructions as you have wrote.  I guess messing with those Erector Sets over the years has helped.

Ken


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## BGHansen (Oct 28, 2015)

4gsr said:


> BGHansen,
> 
> Nice writeup you did on installing a new taper attachment the correct way.  This can also be applied to most any taper attachment out there in the machine world.  New or used.  I've rebuilt, installed a few over the years and yet found detailed instructions as you have wrote.  I guess messing with those Erector Sets over the years has helped.
> 
> Ken


 Hi Ken,

Thanks for the comments.  Probably a lot more detail than anyone wants to read, but I figure my wife would give me "the look" if I talked to her about it!

Best regards, Bruce


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## tmarks11 (Oct 6, 2016)

Thanks for the details.  I finally had enough jobs piled up that I need a taper attachment, so I bought one.

Kind of stupid that Grizzly had drilled and tapped holes for the sheetmetal cover on the back of the carriage, but the holes were not chosen to line up with the taper attachment.  Would make this job a bit easier.

It is kind of strange that the taper body has dovetails on top of it.... and the dovetails are about an inch narrower than the dovetail for the cross slide.  My theory is that this taper body was originally designed for a smaller lathe, that had a smaller carriage....



BGHansen said:


> If I had it to do all over again, I’d clamp a couple of bars to the two lower dovetail surfaces on the carriage and extend them out and over the taper body.... run the cross feed nut back/forth checking it for flushness to the top surface of the carriage dovetail.  If the nut runs uphill as in my initial installation, shim the taper body down appropriately before punching/drilling and tapping the holes to the carriage.



Glad I re-read your review before drilling the holes.  I went a bit further in that I reinstalled the cross slide and screwed the cross feed nut back into it.  That meant the leadscrew was supported at two points, which made it easier to hold the taper body in the correct position against the leadscrew support block while punching hole position.

FWIW, I think that Grizzly should have slotted the attachment screws in the taper body (like you ended up doing).  The "alternate bracket" Grizzly supplied has slots like that, which makes it easier to adjust it so it doesn't put pressure on the leadscrew.



BGHansen said:


> The new cross slide nut was not tapped for screwing to the cross slide.... I didn’t mic the new lead screw vs. the original, but they are subtly different. I couldn’t thread the original nut on the new lead screw, both are 10 tpi.



My new cross slide nut wasn't tapped either.  But it was the exact same size as my old one and threaded easily on the leadscrew.  More spare parts for my spare parts bin.



BGHansen said:


> The new cross feed lead screw far end is attached to the alignment block with thrust bearings on either side of the block and nuts on the far side. I had to add a couple of spacer washers so the cross feed lead screw was tight to the alignment block. Otherwise the cross slide would “chuck” back/forth.



Ditto.  Really seems like they messed up and should have provided another "thrust washer", although it isn't in their parts diagram.  The shoulder on the leadscrew means you can't tighten the nut all the way down.

Of course, by the time I realized that, I have the cross slide off and the old leadscrew out.  OW, it would have taken a few minutes to turn myself the correct size spacer.  It is handy having a lathe.... unless you have it torn apart, and need to use it to make parts for itself.



BGHansen said:


> The bed clamp bracket was about 0.030” thicker than the bed....I machined 0.050” off the surface of the bed clamp bracket above the bed clamp block so it would clamp properly to the lathe bed.



Same problem, same solution.  The instructions say to use the M10-30 screws, but the holes are drilled and tapped for M8 screws, and 30mm would be way too short anyways.  My hardware set came with M8-40 (which I used to bolt the taper body to the carriage), but no other M8 screws longer than 16mm, so I had to make a run to the hardware store.



BGHansen said:


> The taper attachment came with a bracket not used on the Grizzly lathe


The "alternate bracket" is included so that you can take off the taper body and than bolt the slide block to the carriage, if (for some unknown reason) you didn't want to use the lathe with the taper attachment on it.


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## jjtgrinder (Oct 15, 2016)

I also had all these "experiences" installing the taper attachment on my G4003g lathe.  In addition to the things above that BGHansen did , I Had to do things like re-scrape the gibs and stone several surfaces and edges to make it work smoothly. Had to do so many things to install it, that I would consider this to be a taper attachment "kit" rather than a "ready to go" taper attachment.


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## biggdawg (Jan 27, 2018)

i am installing my taper attachment now and all i can say is the instructions suck. good thing i am a mechanic and beginning machinist so i can figure it out after i assemble and take apart a few times because they are so vague or plain wrong.

one question i have is my crossfeed nut was missing the hole like above but in the instructions it refers to it having a threaded hole and to install screw removed when disassembling and to only snug it.  so i took the nut off the old cross shaft and installed it. i am not done yet so don't know if i will be taking it back apart again or not. time will tell.

thanks for the detailed write up it is helping me with my install.


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## wachuko (Dec 31, 2021)

Thank you for the write up!

An accessory that I have on my Grizzly website wishlist... that, along with the 5C collect chuck, carriage stop, ER40 collect chuck, DRO...


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