K&T 2HL horizontal, strange wear and repair
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  1. #1
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    Default K&T 2HL horizontal, strange wear and repair

    I'm working on rebuilding a K&T model 2HL horizontal mill SN 10-3676 and encountered a strange (to me) wear pattern I want to repair. The wear is on the end of item 97 (Spindle drive bevel gear 2HL-D97) where it contacts item 22 (Feed drive sleeve gear 2HL-E22). The parts catalog is too large to attach, but here is a link to identify these parts. Kearney & Trecker Co. - Publication Reprints - Model 1H-2HL Knee Type Milling Macine - Parts Manual | VintageMachinery.org They mesh together when the machine is assembled and 2HL-E22 drives 2HL-D97 when the spindle clutch is engaged.

    Picture "wear 2HL-D97.jpg" wear-2hl-d97.jpg shows the worn area of 2HL-D97. The shiny region is one of three cavities removed from the spline where 2HL-E22 makes contact. Picture "wear 2HL-E22.jpg" wear-2hl-e22.jpg shows the mating region of 2HL-E22 with very little wear.

    I'm thinking to build up the worn areas with silicon bronze using TIG and then hand filing back to the original spline contour. Does anyone have comments on this approach or want to recommend a different way?

    I've also been looking for possible misalignment that might have caused this wear. When I removed the spindle speed gear box, I found that a 0.012 inch shim had been added at the rear face of item 85 (speed box 2HL-D885), the main gear box casting. This displaced the mating end of 2HL-D97 rearward and also changed the mating angle. I suspect the shims were not put there by the factory because the edges of the shims where they were cut for bolt holes are very ragged.

    I've been looking for possible misalignment that the shims might have been installed to correct but have not found any so far. The machined faces on the column where the speed box 2HL-D885 and the pulley bracket 2HL-E17 attach measure 10.625 +/- 0.0005 inch apart and are parallel. I've trammed between the Pulley 2HL-E12 and Pulley bracket 2HL-E17 and there is 0.0015 inch variation. The setup is in Picture "tram 2HL-E17.jpg". tram-2hl-e17.jpg

    So far, I have not found anything that would justify adding the 0.012 shim. I'm thinking that the wear was caused by misalignment introduced by the shim. Does anyone have alternative ideas I should consider or thoughts about how to check other areas for misalignment?

    Walter

  2. #2
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    Your process sounds solid to me. You can almost guarantee it didn’t come from the factory with that shim in there. I sold a lot of parts off the 2HL I scrapped a few months back but I probably have all the replacement parts sitting on the shelf. If you’re interested, let me know.

    Andy

  3. #3
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    I want to follow up on this and let everyone know what I found.

    1) I did the repair of the worn areas on the spindle drive bevel gear using TIG and silicon bronze followed by hand filing and it seems to be OK (I did not take any pictures, sorry). I'm still in the process of re-assembly so I'm not really able to test it under load yet and won't be for several more months.
    2) I found out why the 0.012" shim between one side of the speed gear box and the column was there. When I re-installed the speed gear box, I left out the shim. It mostly went in OK, but just before I tightened down the socket head cap screws, I could see that there was a gap at the rear where the shim was. I went ahead and tightened the screws without the shim. The feed drive shaft turned fine, but the starting lever was really tight and dragging on something. I removed the speed gear box part way and could see a shiny spot on the clutch shifter fork.
    2hl-speed-gear-box.jpg This is a picture of the speed gear box being installed for reference. The shim was located at the rear vertical face where it bolts to the column.
    2hl-shifter-arm-wear.jpg This shows the shiny spot on the clutch shifter fork.
    2hl-shifter-arm-interference-area.jpg This shows where the shifter fork was contacting the column. Apparently the shim was added to rotate the speed gear box and move the shifter fork away from this contact area. So, I filed about 0.04" off of the shifter fork, blued the filed area, re-assembled again without the shim. The starting lever moved freely.
    1hl-filed-area-bluing.jpg And, after pulling out the speed gear box again to look, the blued area showed there was now no contact.
    I've since re-installed the speed gear box with Loctite 515 and without the shim. The engagement between the repaired spindle drive bevel gear and the feed drive sleeve gear seems good to me and the starting lever moves freely.

    My suspicion is that the speed gear box was either replaced or repaired sometime in the past. When I cleaned out the speed gear box cavity in the column, I found a lot of fine metal dust and a badly worn C-shaped piece of steel lying on the bottom that looked like it might have come from a shifting fork. I did not see any serial number on the speed gear box.

    I do feel relieved to know why the shim was there and to have fixed the problem. The next task is disassembly and cleaning the saddle.

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