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Keyway broach bushing slop?

DPittman

DPittman

Ultra Member
How much is too much? I just received my Aliexpress keyway broach set and was surprised that the broach cutter fit so loosely in the bushing on the smaller bushings. The bigger ones are not as bad.

Won't this be potential for crooked keyway?
 
There must be standard broach and bushing dimensions and tolerances for metric and imperial sizes but surprisingly I can't find any such thing in my old Machinists Handbook. There are lettered styles I think the ones I have are all either B or C.
 
I have a several sets of Dumont broaches. The bushings and broach fit with 0.002" clearance. No slop at all.

I would send that set back to Aliexpress.
Broach.jpg
 
If the bigger ones are fine they may have included the incorrect style of broach cutter for the smaller bushings or vice versa. It would be very instructive to know the measurements of the bushing slot and the broach base.
 
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DPittman said:
I think you're right. Oh boy I don't look forward to this.
Click to expand...

Sending it back? not a problem in my experience, not as nice and friendly as Amazon (commercial culture: here the customer is king, there the manufacture is king) but Ali waves a big stick and you get to return things with them paying the shipping.

Agreed it has to go back.
 
Mcgyver said:
Sending it back? not a problem in my experience, not as nice and friendly as Amazon (commercial culture: here the customer is king, there the manufacture is king) but Ali waves a big stick and you get to return things with them paying the shipping.

Agreed it has to go back.
Click to expand...
Yes it looks like returning it won't be so bad but then I loose my UPS fees and have to pay that again if I order again. :mad:
 
Kind of ghetto fix idea but maybe you could bond in feeler gauge stock on either side of broach, using the broach/assembly during the fit up? That way you would have pretty hard rubbing surface. I don't know how much shear force the joint surface would see during broaching if that's even viable. Loctite retainer might be an option. Silver soldering would be tricky. The question is - is the slot too wide or the broach too narrow vs. specs? If the broaches are OK, they should at least send a replacement guide part if you show a pic of the dimensions of both. I'm guessing that making a new guide involves some work, maybe hardened & ground?
 
PeterT said:
Kind of ghetto fix idea but maybe you could bond in feeler gauge stock on either side of broach, using the broach/assembly during the fit up? That way you would have pretty hard rubbing surface. I don't know how much shear force the joint surface would see during broaching if that's even viable. Loctite retainer might be an option. Silver soldering would be tricky. The question is - is the slot too wide or the broach too narrow vs. specs? If the broaches are OK, they should at least send a replacement guide part if you show a pic of the dimensions of both. I'm guessing that making a new guide involves some work, maybe hardened & ground?
Click to expand...
From the YouTube videos I have seen making a new bushing would not be all that hard and doesn't not need to be hardened and ground. I've got Aliexpress ok to return the whole set but I'm hoping to get just the 3 lousy bushings replaced. I really don't want to have to repurchase a whole set and pay courier fees all over again.
 
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