L1 Spindle Back Plate

bug_hunter · Mar 24, 2021

Hey Guys and Gals,

Looking for some information on what lathes use an L1 Spindle Mount or Back Plate. Might not be Antique, but not sure where else to post this question.

I am looking to part with a four-jaw chuck that is fitted with an L1 back plate and trying to figure out who might use this type of mount/back plate.

Any information would be appreciated.

Thanks

Limy Sami · Mar 25, 2021

The spindle nose is usually mentioned on each lathe description here Lathes + Machine Tool Archive

But a an L1 is going to be a good size lathe - what dia' is the chuck?

Andy FitzGibbon · Mar 25, 2021

Many used it. One of the standards of the industry for medium-heavy lathes from (roughly) the early '30s on.

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mmarquette · Mar 25, 2021

L 1 fits my 12” Hendey . Think they fit the 14” not sure about 16” and up haven’t looked it up

bug_hunter · Mar 25, 2021

Limy Sami said:
The spindle nose is usually mentioned on each lathe description here Lathes + Machine Tool Archive

But a an L1 is going to be a good size lathe - what dia' is the chuck?

The chuck (TdeG 4-jaw) and the back plate are 9-inch in diameter.

johnoder · Mar 25, 2021

The chuck (TdeG 4-jaw) and the back plate are 9-inch in diameter.

L1 is found on 12 to 20" (such as the 20 Standard L&S I had)

scatter cat · Mar 25, 2021

My 14" Hendey and 20" bradford both have L1 spindles.

dalmatiangirl61 · Mar 25, 2021

First off, its a face plate, someone used it as a back plate. Secondly its not an L1, or maybe better described as a modified L1, IDK. Post pics and dimensions so people can help you ID it.

bug_hunter · Mar 25, 2021

dalmatiangirl61 said:
First off, its a face plate, someone used it as a back plate. Secondly its not an L1, or maybe better described as a modified L1, IDK. Post pics and dimensions so people can help you ID it.

Please enlighten me on the difference between it being a back plate and a face plate.

Below if a picture of the "plate" along with the dimensions of an L1. How do you see it as being modified?

dalmatiangirl61 · Mar 25, 2021

bug_hunter said:
Please enlighten me on the difference between it being a back plate and a face plate.

Below if a picture of the "plate" along with the dimensions of an L1. How do you see it as being modified?

View attachment 317392 View attachment 317393 View attachment 317394

A face plate is used to drive dogs while working between centers, that is what the elongated notch is for. A back plate is used to mount a chuck, a face plate can be used as a back plate, but most here would have done it differently than was done with the locating pins. Notice an L1 spindle is fully tapered, according to your previous post the tapered section of the face plate is short then goes into a non-tapered section, please give those dimensions again.

bug_hunter · Mar 25, 2021

dalmatiangirl61 said:
A face plate is used to drive dogs while working between centers, that is what the elongated notch is for. A back plate is used to mount a chuck, a face plate can be used as a back plate, but most here would have done it differently than was done with the locating pins. Notice an L1 spindle is fully tapered, according to your previous post the tapered section of the face plate is short then goes into a non-tapered section, please give those dimensions again.

r
The tapered portion of hole on the plate recesses approximately 15/16-inch, then thee is a straight section (perpendicular to the plate) for approximately 7/8-inch, a small reduction in diameter to another straight (perpendicular to the plate) section for approximately 1-1/8-inch. The keyway existing for the entire thickness of the plate.

Thanks for he plate enlightenment:

Dog Slots = Face Plate
No Dog Slots = Back Plate

bug_hunter · Mar 25, 2021

After further Googling, and enlightenment from dalmatiangirl61, it appears that I have an L1 faceplate that was modified to be used as a backplate. When its life began, it may have looking like this:

svs · Mar 25, 2021

I’d say you have a dog drive plate used as a backplate. A faceplate has slots and or t slots to clamp odd work that won’t fit a chuck.

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dalmatiangirl61 · Mar 25, 2021

Pictured below is an L1 face plate, notice it is fully tapered. The center of taper is recessed so that when mounted it locates on base and nose of the spindle, not the center portion. My guess is that was made for a specific machine, but I have no idea what it fits, seems to be a compromise between a short taper (A series) and a long taper (L series), with the threaded outside diameter leaning it more to an L series.

Sorry, new computer and pic uploading is not working the way it used to, I'll try to figure it out.

dalmatiangirl61 · Mar 25, 2021

Sorry for quick hijack of your thread, anyone know steps for uploading pics on windows 10, seems to work same as before but when I click upload, its not uploading the pic.

johnoder · Mar 25, 2021

dalmatiangirl61 said:
Sorry for quick hijack of your thread, anyone know steps for uploading pics on windows 10, seems to work same as before but when I click upload, its not uploading the pic.

Works on my Win 10 - you do have to be in GO ADVANCED

https://www.practicalmachinist.com/...res-south-bend-forum-372508/?highlight=photos

have fun

dalmatiangirl61 · Mar 25, 2021

testing pic

failed

dalmatiangirl61 · Mar 25, 2021

bug_hunter said:
After further Googling, and enlightenment from dalmatiangirl61, it appears that I have an L1 faceplate that was modified to be used as a backplate. When its life began, it may have looking like this:

View attachment 317396

But according to your descriptions, the taper on yours ain't right, so its not an L1. How about drawing us a diagram as if we are looking at it from the side, exaggerate the taper section(s) so we can see where its tapered and where its not, please include dimensions of each diameter.

Edit: You can also do this check, take a 6" ruler, set edge on tapered section, slide it into bore, it should not touch on center recessed section, but should lay flat on larger and smaller diameter sections of the taper. If ruler hits that lip, or only rests on edge of that smaller diameter, something ain't right and its a "special".

johnoder · Mar 25, 2021

In B5.9 Spindle Noses, L1 big end of taper is 4.125 and it is 2.750 long

Taper is 3.500" taper per foot on dia.

bug_hunter · Mar 25, 2021

dalmatiangirl61 said:
But according to your descriptions, the taper on yours ain't right, so its not an L1. How about drawing us a diagram as if we are looking at it from the side, exaggerate the taper section(s) so we can see where its tapered and where its not, please include dimensions of each diameter.

Edit: You can also do this check, take a 6" ruler, set edge on tapered section, slide it into bore, it should not touch on center recessed section, but should lay flat on larger and smaller diameter sections of the taper. If ruler hits that lip, or only rests on edge of that smaller diameter, something ain't right and its a "special".

A dimensioned cross-section is shown below. Forgive the crudeness as I am not a draftsman. Also forgive the incorrect description previously. Upon further review, the taper extend above and below the straight section. All dimensions are in decimal inches. The threaded portion is a nominal 6" dia with a 6 tpi pitch.

L1 Spindle Back Plate

Aluminum

Diamond

Diamond

Cast Iron

Aluminum

Diamond

Aluminum

Diamond

Aluminum

Diamond

Aluminum

Aluminum

Hot Rolled

Diamond

Diamond

Diamond

Diamond

Diamond

Diamond

Aluminum

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