# How Are "slots And Slits" Cut For Bushings?



## EmilioG (Dec 18, 2016)

I would like to learn to correctly cut slits and slots, down to 1/32", (width of slots (.794") in steel to make bushings, sleeves,
etc... Like the slits that you see on R8 collets, grinder collets, reducing sleeves, etc...?

What type of tooling is used to make this fine straight cuts?


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## T Bredehoft (Dec 18, 2016)

EmilioG said:


> 1/32" (.794")


Emil, this is not meaningful. 1/32 is .03125.


EmilioG said:


> What type of tooling is used to make these fine straight cuts?


If  you google 'slitting saws" you will find your answer.


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## Bob Korves (Dec 18, 2016)

If I might slightly hijack, er, I mean add to this thread, I would like to make some split sleeve bushings for boring bar shanks.  What is the work flow sequence for getting from round stock to an accurate thin wall bushing with a full length slit?


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## Ulma Doctor (Dec 18, 2016)

Bob Korves said:


> If I might slightly hijack, er, I mean add to this thread, I would like to make some split sleeve bushings for boring bar shanks.  What is the work flow sequence for getting from round stock to an accurate thin wall bushing with a full length slit?


i'd imagine the rod is drilled and bored, then slit


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## JimDawson (Dec 18, 2016)

EmilioG said:


> I would like to learn to correctly cut slits and slots, down to 1/32" (.794") in steel to make bushings, sleeves,
> etc... Like the slits that you see on R8 collets, grinder collets, reducing sleeves, etc...?
> 
> What type of tooling is used to make this fine straight cuts?
> Thanks so much.



Yup, Slitting saws




Bob Korves said:


> If I might slightly hijack, er, I mean add to this thread, I would like to make some split sleeve bushings for boring bar shanks.  What is the work flow sequence for getting from round stock to an accurate thin wall bushing with a full length slit?



I can think of a couple of ways to do this.  In both cases, turn the bushing to the correct dimensions and part off.

Then over to the mill and put the bushing on a stub arbor, secure with a screw and washer, use a slitting saw and cut right into the washer and the arbor.......OR

Drill a bushing sized hole in a piece of scrap, drop in the bushing, the cut the slit with a band saw right through the scrap and bushing.


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## Billh50 (Dec 18, 2016)

When I used to make them in work. I drilled the ID undersize then turned the ID and OD at same time to be concentric. Then I would hold the part in a vise end against the jaws and just a slight bit of ID visible at side of jaws. Then using a slitting saw I would mill a slot. If multiple slits are needed I would them put a shim in the 1st slot and use a sign bar or angle block to position the part at the right angel to cut next slot.


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## Bob Korves (Dec 18, 2016)

(snip)





JimDawson said:


> Then over to the mill and put the bushing on a stub arbor, secure with a screw and washer, use a slitting saw and cut right into the washer and the arbor...


(snip)
I like the stub arbor idea.


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## EmilioG (Dec 18, 2016)

Indexer may also work.  band saws are too wide. I would need slits 1/32" wide.


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## JimDawson (Dec 18, 2016)

Here is what I used for a slitting saw.  It turns out that Harbor Freight has a little tiny chop saw that has a 2 inch blade on it. The chop saw is not useful to me, but the blades are, and they sell 3 packs of replacement blades. The blades are 2 inch dia, and 0.027 thick, made of M2 HSS, or so the package says. Nice little slitting saws, about $10 for a 3 pack.  Whipped up a quick arbor and started making slots.


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## mikey (Dec 18, 2016)

Bob Korves said:


> If I might slightly hijack, er, I mean add to this thread, I would like to make some split sleeve bushings for boring bar shanks.  What is the work flow sequence for getting from round stock to an accurate thin wall bushing with a full length slit?



I usually drill and ream the stock, then turn the OD profile I want. I put some layout dye on the end of the sleeve and use my center gauge (the V-shaped head on a combination blade) to mark a center line. Then I put the sleeve in a vise so the marked line is even with the top of the jaw and the bore is sticking past the  end of the jaw about half way. A spacer is used on the other end of the jaws to balance the clamping forces, then I use a slitting saw to cut a through slot. I almost always cut an expansion slot 180 degrees from the through slot so I just turn the work piece over, line up the layout line to the top of the jaw and cut the partial slot about 1/2 way through the wall. 

This has worked well for me and I've made a number of sleeves this way.


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## mikey (Dec 18, 2016)

EmilioG said:


> I would like to learn to correctly cut slits and slots, down to 1/32", (width of slots (.794") in steel to make bushings, sleeves,
> etc... Like the slits that you see on R8 collets, grinder collets, reducing sleeves, etc...?
> 
> What type of tooling is used to make this fine straight cuts?



Emilio, you need a slitting saw holder and some slitting saws. Slitting saws come in many sizes and thicknesses but for the thin slits you are looking at, jeweler's saws work well. Most of these smaller saws come with a 1/2" arbor so your holder has to match that diameter. You can either buy the holder or make one - lots of info on this on the net. 

Look at this pdf for more info. Pay particular attention to the tips and tricks section on how to use these saws. They are intended to take full-depth cuts; pecking away at the work wears the blade prematurely. Hope this helps.

http://www.martindaleco.com/pdfs/Metal_Working_Mica_Saws/Saws.pdf


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## EmilioG (Dec 18, 2016)

Thanks to all for the helpful ideas and thanks Mikey, you are a constant source of great advice and as usual, very helpful
and informed.  Making these sleeves and bushings , I think, is a good skill to learn.  So many times, I've need to fit two parts
together, even temporarily, and finding a pre-made part for the ID/OD is not easy to find.
Thanks so much to you all.  The combined experience and talent here is awesome.  I hope to one day have some of the skills
that most of you have.  Have a Merry Christmas and a Joyous Holiday season everyone.  Good luck, Good health and good fortune.


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## Bob Korves (Dec 18, 2016)

mikey said:


> I usually drill and ream the stock, then turn the OD profile I want. I put some layout dye on the end of the sleeve and use my center gauge (the V-shaped head on a combination blade) to mark a center line. Then I put the sleeve in a vise so the marked line is even with the top of the jaw and the bore is sticking past the  end of the jaw about half way. A spacer is used on the other end of the jaws to balance the clamping forces, then I use a slitting saw to cut a through slot. I almost always cut an expansion slot 180 degrees from the through slot so I just turn the work piece over, line up the layout line to the top of the jaw and cut the partial slot about 1/2 way through the wall.
> 
> This has worked well for me and I've made a number of sleeves this way.


I thought of that idea but guessed it would not work very well because of the unsupported tube, which could spring open or closed on the saw, and possibly raise other problems, not the least of them being chatter.  I have the saws and arbor, just don't want to try anything dumb and break a saw while also destroying the work.  I will have to try it and see, though I like Jim Dawson's ideas even though they take more effort to get set up.


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## Tony Wells (Dec 18, 2016)

The spring of the tube is sort of unpredictable, but usually it opens up rather than clamps down on the blade. As long as you are using a non-keyed arbor and haven't overtightened the nut, worst case it just slips. But if you are power feeding, of course this is a problem. This is one time I prefer to have everything backwards. As in the threaded part of the arbor. I would much rather have it loosen the nut and harmlessly spin if it gets hung than tighten up more and break. And I rarely power feed a really small slit/jewelers blade. I don't do a lot of slitting, but I have done my share. There are times when I have pushed tapered shims in behind the cutter if I think there is a chance of it closing up, but I don't recall it ever being needed. 

If you have a close fitting mandrel, cut a wider clearance slot in it where the slit saw will run and you won't have to saw it at the same time as the sleeve or whatever you are slitting. Or if you are using a vise with it held end-ways, leave only enough hanging out of the vise to allow the cut. The vise will minimize any springing either open or closed. One last tip I can think of right now, is to make an exception and climb cut. The saw will have a much better chance of staying straight and this will make it less likely to get in a bind and break. Climbing won't allow it to wander and poses less break risk. I have broken a few fragile saws because of this wandering off milling conventionally.


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## mikey (Dec 19, 2016)

Bob Korves said:


> I thought of that idea but guessed it would not work very well because of the unsupported tube, which could spring open or closed on the saw, and possibly raise other problems, not the least of them being chatter.  I have the saws and arbor, just don't want to try anything dumb and break a saw while also destroying the work.  I will have to try it and see, though I like Jim Dawson's ideas even though they take more effort to get set up.



Never had a saw pinch or have any problems with this process. As the cut completes, it opens up so the saw has never gotten bound up, ever. Moreover, with the right feeds and speeds the saw cuts cleanly - no chatter. With that said, I'm sure there are many ways to do this job - good luck, Bob, and let us know what worked for you.


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## Bob Korves (Dec 19, 2016)

Tony Wells said:


> The spring of the tube is sort of unpredictable, but usually it opens up rather than clamps down on the blade. As long as you are using a non-keyed arbor and haven't overtightened the nut, worst case it just slips. But if you are power feeding, of course this is a problem. This is one time I prefer to have everything backwards. As in the threaded part of the arbor. I would much rather have it loosen the nut and harmlessly spin if it gets hung than tighten up more and break. And I rarely power feed a really small slit/jewelers blade. I don't do a lot of slitting, but I have done my share. There are times when I have pushed tapered shims in behind the cutter if I think there is a chance of it closing up, but I don't recall it ever being needed.
> 
> If you have a close fitting mandrel, cut a wider clearance slot in it where the slit saw will run and you won't have to saw it at the same time as the sleeve or whatever you are slitting. Or if you are using a vise with it held end-ways, leave only enough hanging out of the vise to allow the cut. The vise will minimize any springing either open or closed. One last tip I can think of right now, is to make an exception and climb cut. The saw will have a much better chance of staying straight and this will make it less likely to get in a bind and break. Climbing won't allow it to wander and poses less break risk. I have broken a few fragile saws because of this wandering off milling conventionally.


Yes, I am thinking climb cutting without much cutter protrusion through the I.D. of the bushing.  That would keep more teeth in the cut and the cut forces more in line with the bushing center line.  Does that sound correct?


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## Tony Wells (Dec 19, 2016)

Correct, but as usual, if you have any slack in the lead screw, you have to drag the lock a little. Slit saws don't have much strength in pulling themselves into the material like a larger cutter or end mill, so climbing isn't so bad with them. And they do cut straight when climbing.


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## Bob Korves (Dec 19, 2016)

Tony Wells said:


> Correct, but as usual, if you have any slack in the lead screw, you have to drag the lock a little. Slit saws don't have much strength in pulling themselves into the material like a larger cutter or end mill, so climbing isn't so bad with them. And they do cut straight when climbing.


Thanks, Tony.  Yes, way lock snugged a bit and cutting in the correct direction so the cutter keeps pulling the work away from the backlash.  With a bit of thought climb cutting gets a whole lot less scary...


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## Tony Wells (Dec 19, 2016)

It's usually not as big a deal as some people think, as long as you aren't crowding it, and have a little drag on your side. And of course, that's not for roughing. Lights cuts, and low loads like this slit saw we're talking about.


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## kd4gij (Dec 20, 2016)

I use the same blade that Jim uses.
http://www.harborfreight.com/pack-of-3-2-inch-cut-off-wheels-42805.html
I have these also but made a better arbor.
http://www.harborfreight.com/6-piece-hss-saw-blade-with-mandrel-set-67224.html


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## EmilioG (Dec 21, 2016)

What about starting the slits, half of the depth, on solid round stock, then drilling open the center hole..then finishing the slots?


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## Mach89 (Mar 23, 2017)

Billh50 said:


> When I used to make them in work. I drilled the ID undersize then turned the ID and OD at same time to be concentric. Then I would hold the part in a vise end against the jaws and just a slight bit of ID visible at side of jaws. Then using a slitting saw I would mill a slot. If multiple slits are needed I would them put a shim in the 1st slot and use a sign bar or angle block to position the part at the right angel to cut next slot.


Glad you said that. I don't have much experience cutting slits, but I need to for a project and that's what I was thinking of doing. Thanks for confirming that it works well.


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