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Bushing internal clamping tool

Suzuki4evr

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#1
Hallo guys
Does anyone have an idea for a arbor of somekind to clamp bushing internally to grind the external service. I do not want to use the tailstock for it takes up to much space.

I want something that can be universal for defferant size bushes for example 30mm to 50mm ID. I was thinking of a type of taper arbor with loose tapers that slide fit over a shaft and the end threaded to clamp the bush tight between centers.

Does anyone have a better idea perhaps?
 

Tozguy

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#2
Do you have to grind because the work is hard or do you want extra precision? What tolerances do you have on concentricity?
 

Suzuki4evr

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#3
It is hardend bushes and it is used on bachoes and excavators so not much tolerance,about 1 to 1.25 thousends.
 

Billh50

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#4
Turn an arbor to just fit ID. Drill and tap the end with a large chamfer. Then slit the end several times. Use a flathead or tapered screw to expand the arbor after installing the bushing.
A pipe tap and pipe plug may be used also. They are both tapered and will expand the arbor.
 

Suzuki4evr

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#5
Turn an arbor to just fit ID. Drill and tap the end with a large chamfer. Then slit the end several times. Use a flathead or tapered screw to expand the arbor after installing the bushing.
A pipe tap and pipe plug may be used also. They are both tapered and will expand the arbor.
Sounds good.Would have to make a few of those for different sizes.Thaks Bill
 

Tony Wells

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#6
There is a factory made workholding device precisely for that application. Since a lot of folks here seem to like Shars, I looked to see if they had it. They have a set of 5 for a little over 100 bucks.

http://www.shars.com/precision-expanding-mandrel-5-piece-set

There are quite a few other sources as well.

The advantage would be that these are hardened and precision ground, whereas the shop-made mandrels mentioned above (while they will work prefectly) are not and are not that great on repeating runs once you remove them from the chuck. They are considered "renewable" however and can be used until you just flat out turn them too small for the screws you used to build them. They also do not expand exactly uniformly along the length, they become sort of bell shaped, expanding more on the end and then tapering back down to the turned size. This can be mitigated somewhat by preturning them with the expansion screw in place and some tension put on them to expand. Shops I "grew up" in called those "spuds". Quite useful. I never bothered with a tapered tap and pipe plug though, well rarely. I just tapped them with a plug or taper tap and let that take care of the expanding force using a straight screw. Always seemed easier to find around the shop.
 

mark_f

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#7
If you look at my thread on building the mill arbor, there is a photo of that process. I made a short mandrel that was a snug hand sliding fit to the ID of the bushing. It is drilled the depth of the mandrel area and tapped on the end for a pipe plug. It is split don the sides 180 degrees apart. The mandrel only expands about .001" to lock the bushing. It works well and repeats just fine. I made a set of bushings with it.
 

Suzuki4evr

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#8
If you look at my thread on building the mill arbor, there is a photo of that process. I made a short mandrel that was a snug hand sliding fit to the ID of the bushing. It is drilled the depth of the mandrel area and tapped on the end for a pipe plug. It is split don the sides 180 degrees apart. The mandrel only expands about .001" to lock the bushing. It works well and repeats just fine. I made a set of bushings with it.
Thank you Mark,I am going to try it anyway and I am sure if I clock it evrytime before I start It would be fine. I am also going to harden it so it would last,because I am going to use it quite often.
 

Suzuki4evr

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#9
There is a factory made workholding device precisely for that application. Since a lot of folks here seem to like Shars, I looked to see if they had it. They have a set of 5 for a little over 100 bucks.

http://www.shars.com/precision-expanding-mandrel-5-piece-set

There are quite a few other sources as well.

The advantage would be that these are hardened and precision ground, whereas the shop-made mandrels mentioned above (while they will work prefectly) are not and are not that great on repeating runs once you remove them from the chuck. They are considered "renewable" however and can be used until you just flat out turn them too small for the screws you used to build them. They also do not expand exactly uniformly along the length, they become sort of bell shaped, expanding more on the end and then tapering back down to the turned size. This can be mitigated somewhat by preturning them with the expansion screw in place and some tension put on them to expand. Shops I "grew up" in called those "spuds". Quite useful. I never bothered with a tapered tap and pipe plug though, well rarely. I just tapped them with a plug or taper tap and let that take care of the expanding force using a straight screw. Always seemed easier to find around the shop.
Thank you Tony. I love making my own tools and save some money. I looked for it around where I live,but nobody could help sofar and It is quite urgent now,but will keep looking. Thanks for your input.
 

brino

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#11
a couple more sources for completeness.......

Beall makes some internal expanding collets in the US:
http://www.bealltool.com/products/turning/ix_collets.php
and you can buy single collets from them.

Lee Valley Tools is a reseller for the full set:
http://www.leevalley.com/en/wood/page.aspx?p=71613&cat=1,330,69091

and if you want to make your own, here's a sample:
http://www.hobby-machinist.com/threads/making-one-washer.43058/post-369474
One could be made with whatever step size and depth you need for various bushings.

-brino
 
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Suzuki4evr

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#12
Thanks Dan,that helped a lot. Don't know if it has to be aluminium, but I try steel and aluminium.
 

Suzuki4evr

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#13
Thanks to all who had an input. You all helped with this problem or should I say.........problem solved.
 
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