Craftsman 109.0703 Lead Screw Resolved, But....

[aoresteen]

As many of you know I am rebuilding a 109.0703 long bed that had been stripped of all it's gears. The biggest issue I had to resolve is why there was no pin hole at the gear end of the lead screw.

Here's a top view of a dirty lead screw that HAS the pin but mine is missing:



This type bushing (with a hole) slides over the end of the lead screw and a SP-320 No. 0000 taper 1/2" pin is driven through and this makes an attached gear turn the lead screw:




At 2:20 you can see the bushing being removed in this video:

So why does my 109.0703 not have a hole in the lead screw for the taper pin? This has bothered me for a couple of weeks. Another issue is that when I fitted the plate (bought off of eBay) that holds the gears, the headstock was missing the upper screw hole (under the spindle gear) for the bolt (above video at 2:01) so I had to drill a hole for the bolt.

Yesterday while looking for a casting number on my lathe bed I discovered why these issues were present. Looking at the Craftsman info tag I discovered that I have a 109.0702 not a 109.0703!!!!!!!!!!

Yes, a BFO!!! (Blinding Flash of the Obvious). I can't read. How I thought I had a stripped 109.0703 when in fact, it is the 109.0702 that NEVER had any gears installed is beyond me. Moral: double check those model numbers. Ugh! Dumb!

So now here's my dilemma.

1. Do I drill a straight hole or a tapered hole?

2. If a tapered hole, what bit do I use and where do I get one? The specs for the No. 0000 1/2" tapered pin are:

Large end: 0.109"
Small end: 0.099"

McMaster-Carr Part # 98390A069

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

3. What is the proper tool to use to set the pin in the hole & pein over the top of the pin?

Thanks all!

Tony

 

[benmychree]

That tool would be a 4/0 taper pin reamer, available as a hand reamer with straight or spiral flutes or a high spiral machine reamer, which is my favorite flavor, as they clear the flutes of chips while doing their work, cost would be in the order that I presented them.

 

[markba633csi]

I would keep things simple and just drill a regular hole, then use a roll pin- should be plenty strong enough

 

[benmychree]

I would keep things simple and just drill a regular hole, then use a roll pin- should be plenty strong enough

Good point, a Rol pin exceeds the shear strength of a solid steel pin.

 

[aoresteen]

Thanks. I will get the 0000 reamer and keep it original.

What tool do I use to set the pin head?

 

[Jim F]

Taper pin do not get peened.

 

[aoresteen]

Thanks!

 

[wa5cab]

The first models of the AA machine to appear in the Sears Power Tools or Power & Hand Tools catalog were the models 702 and 703. The 702 was a stripped down version of the 703 that did not include the change gears or associated parts, AA sold as a kit all of the parts necessary for thread cutting. Apparently the lead screw had to be re-positioned and then drilled in place.

The instructions for where and what to drill are in the 702/703 manual or instructions that are available in Downloads. In the manual has a list of the parts that come in the threading kit to turn a 702 into a 703. The drill bit is a #37 and the taper pin is a #4-0 x 1/2". I may have missed it but I did not see any reamer on the list. Nor was it mentioned in the installation instructions.

Later (Post-War) models do not include the stripped down version.

 

[aoresteen]

Thanks Robert! I ordered the tool & parts - I have the #37 drill bit.

I read the 0702 conversion instructions last week and also found no info on drilling the lead screw. Maybe my 109.0702 has a lead screw that was never drilled by mistake, who knows.

I have mounted the Part # 3203 Mounting Plate (part C-4535 for the 109.20630 will also fit; I am not sure on part # C-3645 for the 190.21270) after drilling the top mounting hole in the 3403 Head Stock and the lead screw is correctly positioned - no changes needed. The only issue I had (other than the missing top bolt hole) was that the part of the Mounting Plate that the end of the spindle passes through rubbed against the bottom of the spindle. I fixed that by opening up the pass-through hole of the Mounting Plate a bit using a vertical milling bit in my drill press. It is not critical - the spindle only needs to spin freely.



So when was the 109.0701 introduced? Not much info on it is available.





The model tag is located on the right front bed leg.

 

[wa5cab]

Sears is of course infamous for not giving the Model numbers in the catalogs and for not having any clue to the model number in the catalog number so it isn't possible to guarantee that the first two models are 700 and 701. But assuming that they are, it appears that the two models first appeared in the 1941 Power Tools catalog. The only thing that does not match is that your 701 has a hand crank on the right end of the lead screw whereas the catalog photos all show a hand wheel which we know was on the 702 and 703.

CORRECTiON: My comments in the following paragraph, except for the final sentence, are incorrect. Although none of the drawings or photos are good enough to show it, all of the post-war models of the AA lathes retained the inverted "V" style bed. Including the 109.21280.

One other thing that I will mention is that the 700 series all had Inverted-V beds whereas all of the later models have two round longitudinal rods, one front and one rear. There is, of course, no clue as to why they made they made the change. But I would think that the "V" would be better.