Sunnen mandrels SL series vs PL series

I am trying to expand my mandrel selection in the range of 1" to 2" diameter for through holes (enlarging bushing type things). The Pl series ones are expensive on ebay (about $100 each) the Sl ones are cheaper ($60). What is the functional difference? Is it only a replaceable shoe?

The "SL" style mandrels have not been available for 40 years. There are several style mandrels that replace them they are all with replaceable shoes. What type of parts are you going to hone, how long are the holes? Actually the "PL" mandrels are now called "P28".

If you are just honing an occasional bronze bushing or an aluminuum part, SL mandrels will work. They are diecast pot metal but will last a very long time with only occasional use in soft materials. Only thing replaceable in them is the stone. Stones are still available from several places.

PL mandrels are steel bodies with replaceable shoes and can be configured in several ways. PL mandrels are available with 2 up to 5 stones depending on the length of the parts you are honing. Shoes and stones are current production at Sunnen and are available. The stone selection is extensive depending on material. Yes they tend to be more expensive than the SL mandrels but there are some good deals on ebay compared to the cost of new from Sunnen.

40 years is a long time, I probably don't want those. I am enlarging holes in steel parts that are up to 2-1/2" long. I guess I'll keep looking for P28 mandrels.

You will have "sticker shock" if you price a mandrel from sunken! I like their products and I use them daily, but they have gotten outrageous on their prices?

SBAER said:

40 years is a long time, I probably don't want those. I am enlarging holes in steel parts that are up to 2-1/2" long. I guess I'll keep looking for P28 mandrels.

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Let me know the following and I would be happy to make some recommendations. Heat treat, stock removal, and finish required.

SBAER said:

40 years is a long time, I probably don't want those. I am enlarging holes in steel parts that are up to 2-1/2" long. I guess I'll keep looking for P28 mandrels.

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The SL mandrels are too long for a 2 1/2" part anyway. They are designed for pistons where you are honing a tandem hole part. If you try honing a short part you will be fighting bell mouth where the part gets big on the ends small in the middle.

The P28 stone is 3 9/32" long which is about right. Rule of thumb you want the stone 3/4 to 1/ 1/2 the length of the part for a ideal setup.

Check out Jamison equipment in Emmitsburg Ia the have many used ones for sale the are in the web too


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