A/c M1-60 Arbor Support Drawing

Wheels17

Wheels17

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Well, I'm now working on the drawing for the last remaining missing critical part on my Craftsman Horizontal mill. I did find a metric drawing on line, and I'm working on turning it into a drawing of an M1-60.

Looking at some pictures captured from Ebay, I can see I already have a problem. When I try to scale features off the pictures, I estimate the thickness of the part as 1.5 inches. Based on the metric drawing, I bought 1" stock. If this is done in steel, perhaps that's thick enough.

I know the size of the overarm (1.5") and can estimate the width of the top of the support at 2". The bolt heads look to be 1/2", or a 5/16 bolt for the overarm support bracket. The distance between the center of the overarm and the center of the bearing is 2.875" (but that will be bored in place). The thinnest standard bearings are 5/8 id, 3/4 OD. This also appears to be the diameter of the lug for the arbor support on the top of the bracket. Some of the big decimals come from the 5/16 bolt assumption.

Any comments on the dimensions would be appreciated. I don't have the drawbolt or oiling channel drawn in yet. Dimensions of the diameter of the pinch segments, and their protrusion into the overarm bar are hard for me to estimate. I suppose I could use the same dimensions as the ones on the mill head... thought of that as I was typing.

A second issue is the bearing material. I really don't have any idea of the magnitude of the cutting forces. The metric drawing shows a bronze bearing with an external oil groove and holes. Oillite is readily available, but I don't know if that has adequate bearing capability, nor do I know the proper method to externally oil an oillite . I have heard that if you try to machine the bearing surface, you ruin the properties of the bearing.
 

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Wheels17 said:
Well, I'm now working on the drawing for the last remaining missing critical part on my Craftsman Horizontal mill. I did find a metric drawing on line, and I'm working on turning it into a drawing of an M1-60.

Looking at some pictures captured from Ebay, I can see I already have a problem. When I try to scale features off the pictures, I estimate the thickness of the part as 1.5 inches. Based on the metric drawing, I bought 1" stock. If this is done in steel, perhaps that's thick enough.

I know the size of the overarm (1.5") and can estimate the width of the top of the support at 2". The bolt heads look to be 1/2", or a 5/16 bolt for the overarm support bracket. The distance between the center of the overarm and the center of the bearing is 2.875" (but that will be bored in place). The thinnest standard bearings are 5/8 id, 3/4 OD. This also appears to be the diameter of the lug for the arbor support on the top of the bracket. Some of the big decimals come from the 5/16 bolt assumption.

Any comments on the dimensions would be appreciated. I don't have the drawbolt or oiling channel drawn in yet. Dimensions of the diameter of the pinch segments, and their protrusion into the overarm bar are hard for me to estimate. I suppose I could use the same dimensions as the ones on the mill head... thought of that as I was typing.

A second issue is the bearing material. I really don't have any idea of the magnitude of the cutting forces. The metric drawing shows a bronze bearing with an external oil groove and holes. Oillite is readily available, but I don't know if that has adequate bearing capability, nor do I know the proper method to externally oil an oillite . I have heard that if you try to machine the bearing surface, you ruin the properties of the bearing.
Click to expand...
I don't know anything about your mill, but I do know about Oilite bushings. First, there are MANY different types, made from different metals, sintered with various amounts of open spaces (pores), and factory filled with different lubricants, including stuff like Teflon. The typical grades you can find at a hardware store are machinable. You need to have a sharp, positive rake tool that cuts cleanly or you will smear the metal and close off many of the pores that allow the oil to get to the shaft. The loads on a horizontal mill, even a small one, can be large. I am not sure that hardware store Oilite bushings are stout enough for the loads they will see. Someone else here probably knows what is used for the factory parts.
 
I just uploaded a PDF of the factory drawing on the M1-60.

Note that the original drawing was wider than 11" and whomever scanned it chopped off the right end. Doesn't affect anything important except the details on the two 3/8"-16 tapped holes. I suspect that it originally said something like "3/8"-16 7/8" Full Threads", or maybe "Deep".
 
@wa5cab: Wow! That's great. Now I can get right to making the support, and know I'm making it correctly!

Thank you!

@Bob Korves: I will clearly have to do more research on the bearing, but I'm a way away from that now. I hope someone chimes in.
 
I thought it had been done some time ago. Part of the problem with keeping up with multiple Downloads and Files systems. Unfortunately, we don't have the factory drawing on the associated support bar.
 
M1-60 Arbor Support, in Atlas Mill Bulletin MMB-3 shows two bushings for the arbor. No dimensions are shown, but FWIW the suggestion is the combined length is shorter than the total length of the bore leaving a small oil reservoir between the two bushings. That would allow for adding oil to solid bronze bushings.

Spiral_Chips

View attachment 124828

PS: The BD1-18 bushing is available from Searspartsdirect.com for $7.49 each. 2 Required.

M1-60_Arbor_Support.jpg
 
When we used to machine Oilite bushings for Sikorsky Aircraft, the finished bushing had to be submerged in a heated oil bath to replenish any oils lost because of heat generated from machining.
 
Back when I was still restoring vintage Land Rovers I used to keep my stock of clutch pilot bushings in a 1# coffee can half filled with SAE 30.

If Sears Parts Direct still has the arbor bushings, so will Clausing.

The M1-8 and M1-60 both have a W30-16 oiler (style is straight with spring-loaded cap).
 
Guys, thanks for the help. I dug around and captured all the pages for my mill from the parts website. I was stunned at what they were charging for some of the parts. $80.49 for the lock pin on the bull gear. $143.99 for the crank for the table (and it's not even the original part!!) $141.99 for the y axis nut. Oilers for $20 to $30.

I can see why you see these machines parted out on ebay...

The bearings seem reasonable at only 2x the generic part price.
 
Clausing is usually less expensive than Sears.

The parts manuals for all of the mills are in Downloads. And include several pages of operating instructions plus a lube chart. The original MMB-5 did not have the instructions but I recently edited it to add them. MMB-5 has parts for all 12 models, albeit the part drawing for the base and "A" models is not as easy to use as the ones for the "B" and "C" models. Fortunately, aside from the cone pulleys and the arbor support on the "C". everything looks pretty much the same even if some part numbers are different.
 
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